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Bibliography on: Biofilm

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ESP: PubMed Auto Bibliography 14 Jul 2025 at 01:39 Created: 

Biofilm

Wikipedia: Biofilm A biofilm is any group of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPS). The EPS components are produced by the cells within the biofilm and are typically a polymeric conglomeration of extracellular DNA, proteins, and polysaccharides. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, biofilms are frequently described metaphorically as cities for microbes. Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial and hospital settings. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single-cells that may float or swim in a liquid medium. Biofilms can be present on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease. Microbes form a biofilm in response to many factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics. When a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.

Created with PubMed® Query: ( biofilm[title] NOT 28392838[PMID] NOT 31293528[PMID] NOT 29372251[PMID] ) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2025-07-13
CmpDate: 2025-07-11

Mori M, Fassi EMA, Villa F, et al (2025)

Nature-Inspired Compounds Targeting Escherichia coli WrbA as Biofilm-Modulating Agents: Computational Design, Synthesis, and Biological Evaluation.

Archiv der Pharmazie, 358(7):e70049.

Biofilms pose significant challenges in multiple settings due to their resistance to conventional treatments. In this study, we designed and synthesized a novel class of nature-inspired 5,7-dihydroxy-2,2-dimethylchroman-4-one derivatives as binders of WrbA, a potential target for biofilm modulation. Using a structure-based computational approach, a small library of analogs with varied amide moieties was developed and synthesized. The evaluation of their binding affinity to WrbA demonstrated good-to-excellent Kd values, as confirmed by microscale thermophoresis (MST). Antibiofilm assays against Escherichia coli and Staphylococcus aureus revealed different modulating effects on biofilm formation, conceivably linked to ROS production. These findings emphasize the importance of ROS levels in biofilm, as well as the pivotal role of WrbA as a target in its regulation.

RevDate: 2025-07-11

Hu DX, Liang J, Yan J, et al (2025)

Butenolide synergises with vancomycin to eradicate pre-formed biofilm of Staphylococcus aureus by interfering with energy-associated metabolism.

Biofouling [Epub ahead of print].

Bacterial biofilms significantly contribute to persistent infections and the emergence of drug resistance of Staphylococcus aureus. Integrating conventional antibiotics with antibiofilm agents represents a promising strategy for combating biofilm-associated infections. This study systematically investigated the antibiofilm activity and underlying mechanisms of butenolide (BU) against methicillin-resistant S. aureus (MRSA), with a focus on the synergistic effects between BU and vancomycin (VAN). BU exhibited dual antibiofilm activities by efficiently preventing biofilm formation and eradicating established biofilms. Phenotypic characterisation revealed that 200 μg/mL of BU suppressed extracellular DNA production and autoaggregation of MRSA, leading to a significant reduction in biofilm thickness, biovolume, and coverage by up to 30%, 98%, and 96%, respectively. Transcriptome and quantitative-PCR analyses showed that BU treatment downregulated the expression of genes involved in energy metabolism. Notably, BU exhibited promising synergistic and additive effects with VAN in eradicating pre-formed biofilms, achieving synergy or additivity in five out of six S. aureus clinical strains tested, with a minimal fractional inhibitory concentration index as low as 0.375. These results highlight the potential of BU as an effective antibiofilm agent for preventing S. aureus-related infections.

RevDate: 2025-07-13
CmpDate: 2025-07-10

Hammouda ZK, Wasfi R, NF Abdeltawab (2025)

Fexofenadine HCl enhances growth, biofilm, and lactic acid production of Limosilactobacillus reuteri and Bifidobacterium longum: implications for allergy treatment.

BMC microbiology, 25(1):430.

BACKGROUND: It is evident that various drugs influence the gut microbiota, yet the precise mechanism driving these effects remain ambiguous. Considering the growing recognition of gut microbiota's role in health and disease, it is important to explore how commonly used drugs, such as antihistamines, may alter microbial composition and function. Histamine, an essential interkingdom signaling molecule, shapes bacterial virulence, biofilm formation, and immune regulation. However, the effects of antihistamines on bacterial colonization are mostly unknown. This study aimed to investigate the potential effects of antihistamine exposure on critical factors which affect the pathogenicity and colonization of selected gut bacterial species, such as growth, biofilm formation, and adherence to cell lines, at intestinal concentrations. If antihistamines influence bacterial metabolism or composition, they may consequently affect Short Chain Fatty Acid (SCFA) production, which could have downstream effects on gut homeostasis and immune function. Specifically, we examined the impact of three antihistamines - fexofenadine HCl, cyproheptadine HCl, and desloratadine -on bacteria from the four dominant gut phyla: Bifidobacterium longum, Limosilactobacillus reuteri, Bacteroides fragilis, and Escherichia coli.

RESULTS: Our results showed that cyproheptadine HCl and desloratadine inhibited the growth of all tested bacteria, whereas fexofenadine HCl promoted the growth of all species except B. longum. Furthermore, cyproheptadine HCl and desloratadine reduced the biofilm-forming capacity of these bacterial species and altered their effects on adherence to Caco-2/HT-29 cell lines aligning with changes in cell surface hydrophobicity: increased cell surface hydrophobicity correlated with greater bacterial adherence to surfaces. In contrast, fexofenadine HCl enhanced biofilm formation and adherence of B. longum and L. reuterii in Caco-2/HT-29 co-cultures. It also led to increased production of lactic and propionic acids, with a statistically significant increase observed in acetic acid levels (p < 0.05).

CONCLUSION: In summary, our findings suggest that fexofenadine HCl, unlike cyproheptadine HCl and desloratadine, supports the growth, and colonization of probiotic bacteria such as L. reuteri and B. longum with potential anti allergic benefits, and enhancing their SCFA production. Conversely, cyproheptadine HCl and desloratadine suppressed bacterial growth, hinting at potential antimicrobial properties that may warrant exploration for drug repurposing.

RevDate: 2025-07-10

Anonymous (2025)

Correction to "Bacterial Diversity of Marine Biofilm Communities in Terra Nova Bay (Antarctica) by Culture-Dependent and -Independent Approaches".

Environmental microbiology, 27(7):e70135.

RevDate: 2025-07-10

Ma R, Zhao H, Zhao Y, et al (2025)

Interaction effects in microbiota-filter media-pharmaceutical in biofilm-based reactors: a case study of anoxic biofilters.

Environment international, 202:109669 pii:S0160-4120(25)00420-9 [Epub ahead of print].

The removal of micropollutants, particularly pharmaceuticals, from wastewater remains a significant challenge due to their persistence and complex degradation mechanisms. Biofilm-based systems offer a promising solution due to their high microbial diversity and metabolic versatility. However, interactions between the microbiota and pharmaceuticals in these reactors remain inadequately explored. This study represented a pioneering investigation into the interactions among microbiota, filter media and pharmaceuticals in anoxic biofilters under the stress of mixed-pharmaceuticals. Under autotrophic conditions, microbial community exhibited improved adaptability to pharmaceutical stress with minimal differentiation. Introduction of pharmaceuticals increased the complexity of microbial co-occurrence networks, with autotrophic biofilters showing a higher proportion of positive correlations. Community assembly was primarily driven by drift, nevertheless, pharmaceuticals shifted community towards increased deterministic assembly, especially enhancing homogeneous selection (HoS) in autotrophic bio-ceramic filters (34.59 %), HoS drove community succession, with deterministic processes shaping taxonomic shifts. Thiobacillus was identified as a keystone taxon in autotrophic filters, demonstrating high abundance, strong competitive ability, and emerged as a pivotal genus contributing to biofilm homogenization and stability. Positive correlations were identified between pharmaceutical molecular weight, hydrogen bond donors/acceptors and removal rates (p ≤ 0.05), resulting in preferred adsorption of pharmaceuticals with high molecular weight by filter media. Therefore, this study proposed the interaction mechanism of "pharmaceuticals preferred adsorption - biofilm homogenization - carbon and nitrogen co-metabolism", which underscored its significance in optimizing biofilm-based processes for precise design and regulation of the microbiota in biofilm reactors.

RevDate: 2025-07-10
CmpDate: 2025-07-10

Romero AI, Surkov S, Wirsén P, et al (2025)

LubriShieldTM-A permanent urinary catheter coating that prevents uropathogen biofilm formation in vitro independent of host protein conditioning.

PloS one, 20(7):e0328167.

Catheter-associated urinary tract infection is one of the most common healthcare-associated infections, with biofilm formation playing a key role in its pathogenesis. Indwelling medical devices introduce ideal pathways inside the body for pathogens and feature surfaces conducive to biofilm development, often leading to severe clinical infections recalcitrant to antimicrobials. When bacteria and fungi switch to biofilm mode of growth, they produce a matrix in the form of extracellular polymeric substances (EPS). This creates a unique environment for growing virulent colonisers and persisting cells while forming a shielding barrier against immune system attacks, antimicrobial agents and mechanical removal by fluid shear forces. To address this challenge, LubriShieldTM - a novel permanent coating - was invented and evenly applied to both internal and external surfaces of indwelling urinary Foley catheters. Without releasing active substances, it effectively prevented pathogens from producing biofilm. The superhydrophilic coating, incorporating a proprietary anti-fouling ligand, significantly inhibited colonising uropathogens from forming biofilm for up to 14 days in artificial urine medium without microbial killing (up to 99% reduction, P < 0.001). In a glass bladder flow model, LubriShieldTM still significantly reduced biofilm formation by 83% (P < 0.0001). Importantly, LubriShield™ maintained its antibiofilm efficacy even after conditioning with fibrinogen, a host-derived protein known to promote bacterial attachment (P = 0.007). RNA-seq analysis revealed significant downregulation of genes associated with microbial EPS formation on the coated surfaces. Additionally, microorganisms adhering to LubriShieldTM coated catheters showed a 78% increased susceptibility to antibiotics compared to those on uncoated catheters (P = 0.004).

RevDate: 2025-07-10
CmpDate: 2025-07-10

Borges MHR, Miranda LFB, Malheiros SS, et al (2025)

The role of citric acid in denture cleansing: Effects on biofilm reduction and corrosion resistance of Co-Cr alloys.

Brazilian oral research, 39:e070.

This in vitro study evaluated the effects of citric acid (CA) on surface properties, biofilm removal, and electrochemical performance of Co-Cr alloys compared to common denture cleansers. Co-Cr discs were divided into five groups based on the decontamination solution: NaCl 0.9% (control), Corega Tabs®, Periogard®, and 10% CA. The surface was characterized at baseline in terms of morphology, topography, and chemical and phase composition. Surface properties, including microhardness, wettability, and roughness, were assessed before and after exposure to each solution. Microbial viability, metabolic activity, and morphology of the polymicrobial biofilm were assessed after treatment to evaluate the efficacy of the decontamination solutions. Electrochemical and morphological evaluations were performed to assess the impact of each solution on the alloy's corrosion process. No significant changes in microhardness were observed (p > 0.05). Decontamination solutions significantly increased surface hydrophilicity (p < 0.05) and roughness, though Ra values remained below the threshold for bacterial colonization. All denture cleansers significantly reduced biofilm viability compared to NaCl (p < 0.05), with no viable colonies post-treatment. The CA group showed a significant reduction in bacterial metabolic activity compared to NaCl and Periogard® (p < 0.05), indicating superior biofilm disruption. Electrochemical tests demonstrated that CA maintained a stable Cr-oxide passive layer, evidenced by nobler OCP values and lower icorr and corrosion rates compared to Periogard® (p < 0.05). SEM images revealed pitting corrosion in all groups, except CA. These findings suggest that CA is a promising and safer alternative for denture care, offering effective antimicrobial action while preserving the electrochemical integrity of Co-Cr alloys.

RevDate: 2025-07-10

Enggardipta RA, Akizuki M, Sekine K, et al (2025)

Antibacterial efficacy of chitosan nanoparticles against Enterococcus faecalis in planktonic and biofilm forms.

Journal of applied microbiology pii:8196184 [Epub ahead of print].

AIM: To evaluate antibacterial efficacy of chitosan nanoparticles (CNPs) as a root canal irrigants against Enterococcus faecalis in planktonic and biofilm forms.

METHODS AND RESULTS: CNPs synthesized using high molecular weight (HMW) and low molecular weight (LMW) chitosan via modified ionic gelation were characterized. E. faecalis biofilm formation and CNPs antibacterial activity against mature biofilms were evaluated via crystal violet (CV) staining, scanning electron microscope (SEM), adenosine triphosphate assay, colony forming unit counting, and live/dead staining. CNPs showed spherical morphology (size = 137.1 and 343 nm, PDI = 0.12 and 0.14, and zeta potential = 43.45 and 42.49 mV [LMW and HMW, respectively]). CNPs significantly reduced biofilm biomass and E. faecalis viability compared to negative control (p < 0.05) in biofilm formation. In mature biofilms, CV staining and SEM showed no biofilm biomass reduction in CNPs groups. However, other assays revealed significantly lower E. faecalis viability in CNPs groups than in the negative control (p < 0.05). HMW- and LMW-CNPs exhibited similar antibacterial properties.

CONCLUSIONS: CNPs, regardless of molecular weight, exhibited antibacterial efficacy against E. faecalis by decreasing biofilm formation and bacterial viability.

RevDate: 2025-07-11

Muturi P, Mbae C, Kibet E, et al (2025)

Antimicrobial resistance and biofilm formation in rarely reported Salmonella enterica serovars from patients presenting with gastroenteritis in Nairobi, Kenya.

Frontiers in microbiology, 16:1628784.

Non-typhoidal Salmonella infections are a significant global public health concern, causing approximately 150 million illnesses and 60,000 deaths annually, with majority of the cases occurring in low- and middle-income countries. In this study, we used whole genome sequencing to identify and characterize uncommon non-typhoidal Salmonella serovars isolated from patients presenting with gastrointestinal symptoms in the Mukuru area of Nairobi, Kenya. Sixteen less common NTS serovars (excluding Salmonella Typhimurium and S. Enteritidis) were identified from 25 patients, with 1 isolate from blood and 24 from stool samples. The most common serovar was S. Newport, isolated from 6 of the 25 patients, followed by S. Breda (2 patients), S. Eastbourne (2 patients), S. Orion (2 patients) and 12 other serovars, each isolated from a single individual. These serovars displayed diverse antigenic profiles, grouped into 9 distinct serogroups. Antimicrobial resistance profiles and in vitro biofilm formation of the isolates were also assessed. Antimicrobial resistance was detected in three S. Newport strains: two sequence type 31 (ST31) isolates carried the bla TEM-1 and tet(A) resistance genes, while one ST166 isolate carried bla TEM-1, tet(A), aph(6)-Id, and sul2. Biofilm formation varied among the serovars and was enhanced by cholesterol while inhibited by bile. Strong biofilm formation was observed in S. Breda, S. Hann, and S. Eastbourne, whereas S. Chicago and S. Kentucky formed weak biofilms. This study highlights the diversity of NTS serovars circulating in Nairobi and emphasizes on the importance of localized studies in addressing regional variations in NTS epidemiology. To effectively mitigate the burden of NTS infections and curb the spread of AMR, sustained genomic surveillance, the development of advanced diagnostic tools for emerging S. enterica infections, and the implementation of integrated public health interventions are essential.

RevDate: 2025-07-12
CmpDate: 2025-07-09

Kissmann AK, Mildenberger V, Krämer M, et al (2025)

Anti-biofilm peptides can rescue fluconazole and amphotericin B efficacies against Candida albicans.

Scientific reports, 15(1):24593.

Candida albicans infections are a global health thread and challenge healthcare environments due to acquired resistances against prominent antifungals like amphotericin B and fluconazole, which additionally have severe adverse effects. The peptide Pom-1 originally isolated from the freshwater mollusk Pomacea poeyana, and its derivatives Pom-1 A-F have proven their potential against biofilms of clinical C. albicans isolates and were suspected to act without candidolytic pore-formation. Here, Pom-1 and its derivatives were shown to act as neutralizing antimicrobial peptides (nAMPs) inhibiting cell-cell interactions and hence biofilm formation. Combining Pom-1 nAMPs with fluconazole and amphotericin B restored their efficacy against resistant C. albicans isolates. Addition of Pom-1 nAMPs allowed to reduce required concentrations to 10-50% below their described effective therapeutic doses. This opens doors not only to mitigate adverse effects of fluconazole and amphotericin B therapies, but also towards novel combination therapies against C. albicans as a severe re-emerging pathogen.

RevDate: 2025-07-12

Yang X, Zhou Y, Zhang L, et al (2025)

Enhanced biofilm formation and municipal wastewater treatment efficiency using granular activated carbon modified bio-ball carriers in moving bed biofilm reactor.

Bioresource technology, 435:132947 pii:S0960-8524(25)00913-7 [Epub ahead of print].

This study introduces a novel enhancement to biological wastewater treatment by integrating Granular Activated Carbon (GAC) with plastic bio-balls in a Moving Bed Biofilm Reactor (MBBR) configuration treating municipal sewage. The resulting GAC-MBBR system demonstrated significantly improved treatment efficiency, achieving 81.8 % carbon and 74.9 % nitrogen removal under high loading conditions-outperforming the conventional plastic-MBBR (64.5 % and 62.7 %, respectively). The macroporous structure of GAC provided increased surface area, promoting superior biofilm growth and microbial retention. Enrichment of key functional genera, including Zoogloea, Thauera, Nitrospira, and Nitrosomonas, was observed, indicating enhanced nitrification potential. Additionally, greater biomass accumulation on GAC carriers underscored their effectiveness in supporting microbial aggregation. These findings suggest that incorporating GAC into MBBR systems offers a promising strategy to optimize biofilm development and improve nutrient removal in wastewater treatment.

RevDate: 2025-07-09

Sroor FM, El-Sayed AF, M Abdelraof (2025)

Design, synthesis, and antimicrobial activity of new thiourea-uracil derivatives: Anti-biofilm, ROS, DHFR, computational and SAR studies.

Bioorganic chemistry, 163:108719 pii:S0045-2068(25)00599-1 [Epub ahead of print].

A new series of thiourea derivatives bearing uracil ring was synthesized. The reaction of 5-amino uracil with isothiocyanate derivatives afforded the corresponding thiourea-uracil derivatives in excellent yields. The antimicrobial activity of the synthesized thiourea-uracil derivatives was successfully determined against different pathogen types. Interestingly, some derivatives such as TUU-05 and TUU-08 show a potent impact on microbial proliferation with a notable MIC value, particularly in the case of Aspergillus niger (7.5 ± 2.11 μg/mL). Accordingly, compound TUU-08 was considered a promising antimicrobial agent that could release elevated Reactive Oxygen Species (ROS) and inhibit the bacterial Dihydrofolate Reductase (DHFR) enzyme at lower IC50 (7.29 ± 0.02 μM) compared with methotreaxat (IC50 = 6.55 ± 0.05 μM). Molecular docking analyses revealed that the most active compounds TUU-01, TUU-02, and TUU-08 exhibited strong binding affinities and targeted interactions with key antimicrobial-associated enzymes: Aspergillus niger, Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Molecular docking analyses revealed that the most active compounds TUU-01, TUU-02, and TUU-08 exhibited strong binding affinities and targeted interactions with key antimicrobial-associated enzymes: Aspergillus niger, Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Computational ADMET profiling further indicated that TUU-01, TUU-02, and TUU-08 adhered to Pfizer's drug-likeness criteria, displaying favorable physicochemical properties, high predicted oral bioavailability and low toxicity risks. Molecular dynamics simulations corroborated the stability of these interactions, particularly for TUU-02, which showed RMSD values of 0.35-0.55 nm (A. niger), 0.25-0.35 nm (C. albicans), 0.20-0.25 nm (P. aeruginosa), and 0.18-0.25 nm (S. aureus), alongside moderate structural flexibility (RMSF: 0.10-0.9 nm). Additional metrics-including solvent-accessible surface area (SASA: 200-230 nm[2], 85-95 nm[2], 125-135 nm[2], 130-140 nm[2]) and radius of gyration (Rg: 2.2-2.4 nm, 1.80-1.90 nm, 1.55-1.60 nm, 1.80-1.90 nm) highlighted the compactness and solvent interaction profiles of the complexes.

RevDate: 2025-07-09

Thakur V, Chalana A, Gupta A, et al (2025)

Dual-species biofilm of MDR Acinetobacter baumannii and Klebsiella pneumoniae are Susceptible to Colistin-Rifamycin Combination Therapy.

Journal of applied microbiology pii:8195522 [Epub ahead of print].

BACKGROUND: Co-infections by MDR Acinetobacter baumannii and Klebsiella pneumoniae pose daunting challenges in healthcare settings. This study aimed at investigating the biofilm formation potential of their co-culture and evaluating the effect of combination therapy.

METHOD: Spatial distribution of A. baumannii and K. pneumoniae in co-cultured biofilm was analysed by Confocal Laser Scanning Microscopy (CLSM) with Green Fluorescent Protein (GFP) and mCherry-tagged strains and Field Emission Scanning Electron Microscopy (FESEM). The antibiotic combination was selected through checkerboard assay and its antibiofilm activity was assessed against the co-culture of MDR strains.

RESULTS: Cell free supernatant of K. pneumoniae enhanced the planktonic and biofilm growth of A. baumannii. Co-culture of these pathogens revealed interspersed growth in close proximity and significantly higher biofilm than their monocultures (p-value < 0.01). Synergistic combination of colistin (MIC/8) and rifamycin (MIC/4) at Fractional Inhibitory Concentration (FIC) killed both the pathogens in monoculture within 3 h. However, the co-culture exhibited enhanced resistance requiring 24 h for complete eradication. Biofilm formation was inhibited by 77% at 2 × FIC. Whereas, the preformed biofilm was eradicated by 40% at 3 × FIC (1/4th of Minimum Biofilm Eradication Concentration). CLSM confirmed structural disruption of the biofilm matrix post-treatment at 3 × FIC, with reduction in biofilm thickness from 7 to 4 µm.

CONCLUSION: A. baumannii and K. pneumoniae co-exist harmoniously, forming enhanced biofilms in co-cultures. Colistin-rifamycin combination proved highly effective against these dual-species biofilms.

RevDate: 2025-07-09
CmpDate: 2025-07-09

Astrada A, Nakagami G, Kashiwabara K, et al (2025)

Biofilm detection-based wound management in diabetic foot ulcers: a randomised controlled trial.

Journal of wound care, 34(7):514-524.

OBJECTIVE: This study aimed to investigate the effectiveness of wound blotting-guided biofilm management in diabetic foot ulcers (DFUs) and to compare it to standard of care (SoC).

METHOD: This double-blinded, randomised controlled trial was conducted at an outpatient clinic in Pontianak City, Indonesia in September-November 2017 and June 2018-November 2019. Adults with diabetes with at least a two-week DFU located below the knee were included. Patients in the control group received SoC followed by the application of any appropriate dressings. Patients in the intervention group in addition to SoC also received additional wound cleansing according to the wound blotting result and antimicrobial dressing. Wound treatment was performed weekly for three weeks. Primary and secondary objectives were: the reductions in total depth; maceration; inflammation/infection; size; tissue type; type of wound edge; tunnelling/undermining (DMIST) score; and percentage of biofilm removal.

RESULTS: A total of 162 participants were recruited. There were significant differences in the total DMIST score at week 3 (p<0.01) between groups and biofilm percentage reduction at week 1 (p=0.01) and week 2 (p=0.03).

CONCLUSION: The findings of this RCT showed that the intervention could significantly improve DFU healing and maximise biofilm elimination, especially after two weeks of treatment. A further study with a longer period of intervention, such as 12 weeks, is suggested to further evaluate the effectiveness of this intervention.

RevDate: 2025-07-09

Long HZ, Tang W, Huang MY, et al (2025)

Discovery of Dual-Acting Biofilm Inhibitors against Pseudomonas aeruginosa by the Coupling of 3-Hydroxypyridin-4(1H)-ones with N-Phenylamide QS Inhibitors.

Journal of medicinal chemistry [Epub ahead of print].

Pseudomonas aeruginosa (P. aeruginosa) is prevalent in hospital infections and strongly complicates the treatment for its propensity to cause biofilm-associated resistance. Herein, a series of novel dual-acting biofilm inhibitors were designed and synthesized by coupling 3-hydroxypyridin-4(1H)-ones with N-phenylamides quorum sensing inhibitors. The hit compound 19l (IC50 = 0.33 ± 0.06 μM) demonstrated significant biofilm inhibition compared to previously reported 3-hydroxypyridin-4(1H)-one derivatives in vitro. Mechanistic studies revealed that there was a decreased production of virulence regulated by quorum sensing system and a lack of iron acquisition under the treatment of 19l, which led to the inhibition of biofilm. More importantly, 19l demonstrated significant antibacterial synergistic effects in the mice wound infection model, enhancing the antibacterial activity of ciprofloxacin and tobramycin by 1000-fold and 200-fold, respectively. Therefore, our study highlighted the clinical application potential of dual-acting biofilm inhibitory strategies and 19l may be a potent antibacterial synergist to combat P. aeruginosa infections.

RevDate: 2025-07-09

Wang Z, Lv X, Kong L, et al (2025)

The c-di-GMP Metabolic Gene pdeN Interacts with LacY and ManZ to Modulate Biofilm Formation in Avian Pathogenic Escherichia coli.

Advanced biology [Epub ahead of print].

Bis-(3'-5')-cyclic diguanylic acid (c-di-GMP), a ubiquitous secondary messenger, affects multiple biological characteristics, including biofilm formation in avian pathogenic Escherichia coli (APEC). C-di-GMP is synthesized by diguanylate cyclase harboring a GGDEF domain and degraded by phosphodiesterase harboring either an EAL or an HD-GYP domain. However, the roles of PdeN, encoding a CSS-EAL domain, are uncharacterized. In this study, it is demonstrated that lacking pdeN significantly promotes biofilm formation and reduces the motility of the clinically isolated APEC O2 serotype strain DE17. In addition, macrocolony morphotypes showed that the ΔpdeN strain exhibits increasing production of curli fibers and cellulose, which is consistent with the results of RNA-seq and qPCR. Further exploration shows that lactose permease LacY and mannose permease subunit ManZ interact with PdeN. Infection experiments show that lacking pdeN significantly reduced the release of LDH in HD-11 cells and adhesion capacity to DF-1 cells. In conclusion, c-di-GMP metabolic gene pdeN involves biofilm formation and pathogenicity of APEC. Besides, it interacts with LacY and ManZ. Those results provide a basis for the prevention and control of APEC from the perspective of biofilm and carbohydrate metabolism.

RevDate: 2025-07-10

Song JX, Scales BS, Nguyen M, et al (2025)

Close encounters on a micro scale: microplastic sorption of polycyclic aromatic hydrocarbons and their potential effects on associated biofilm communities.

Environmental microbiome, 20(1):84.

BACKGROUND: Within systems as dynamic as the aquatic environment, it is crucial to address the impacts of an ever-growing network of emerging pollutants at their intersection. With previous research having demonstrated the capacity of microplastics (MPs) to sorb persistent organic pollutants, we ask in our study how different plastic polymers that are found throughout aquatic systems interact with polycyclic aromatic hydrocarbons (PAHs) and how this intersection of pollutants might impact the bacterial communities that form on MP surfaces. We performed an in situ incubation experiment at different sites along the Baltic Sea coast and through a PAH and 16S amplicon analysis, we investigated the sorption patterns of different substrates and their potential impacts on associated biofilm communities.

RESULTS: PAH sorption patterns of polyethylene (PE), polystyrene (PS), and aquaria stone were found to be dictated predominantly by substrate type and secondly by incubation site. While PE showed a general positive trend of sorption, stone rather leached PAHs into the environment, whereas the PAH levels of PS remained relatively unchanged following incubation. These sorption patterns correlated significantly with the composition of biofilm communities observed on all three substrate types after a 6-week incubation period. Strong correlations between specific PAHs and bacterial taxa indicate a direct relationship between these factors. Elevated levels of specific 3- and 4-ring PAHs on PE and PS coincided with higher proportions of specific taxa reportedly capable of hydrocarbon utilisation as well as a reduced diversity among biofilm communities.

CONCLUSION: The findings in our study highlight the importance of investigating contaminants such as MPs holistically, including any associated substances, to fully understand how they impact surrounding ecological systems as they traverse the different compartments of the aquatic ecosystem.

RevDate: 2025-07-08

Gao PP, Shen XX, Chen YC, et al (2025)

MR-10 peptide from Cordyceps militaris enhances thermotolerance in Lacticaseibacillus paracasei R21 by preserving membrane integrity and promoting biofilm formation.

Microbiological research, 300:128266 pii:S0944-5013(25)00225-3 [Epub ahead of print].

Protein hydrolysates derived from the mycelium of Cordyceps militaris (C. militaris) have shown potential as thermoprotective agents for lactobacilli. To identify the peptides responsible for this effect, albumin and glutenin were separately extracted from C. militaris and hydrolyzed. Results showed that glutenin peptides in the 5-10 kDa range provided optimal protection for Lacticaseibacillus paracasei R21 (L. paracasei R21) during exposure to 65°C for 20 min. A 1 % concentration of these peptides increased viable L. paracasei R21 counts by 2.05 log CFU/mL compared to unsupplemented conditions. Among the five peptides identified by LC-MS/MS, MR-10 (MAVNLVPFPR) exhibited the strongest thermoprotective effect. Adding 0.5 % MR-10 during heating increased cell survival by 0.89 log CFU/mL. Structural analysis of L. paracasei R21 cells exposed to 65°C revealed progressive damage to the membrane, cell wall, and DNA, with membrane damage identified as the main cause of cell death. MR-10 significantly improved cell survival by preserving membrane integrity and morphology, as observed via inverted fluorescence and scanning electron microscopy. Multi-omics analyses revealed that MR-10 participates in peptide transport via ABC transporters, promotes biofilm formation, and boosts fatty acid synthesis. Collectively, these processes reinforce membrane stability and protect cells from heat stress.

RevDate: 2025-07-08

Bowden LC, Sithole ST, Walton EC, et al (2025)

Copper-coated carbon-infiltrated carbon nanotube surfaces effectively inhibit Staphylococcus aureus and Pseudomonas aeruginosa biofilm formation.

Applied and environmental microbiology [Epub ahead of print].

Implant-associated infections caused by Staphylococcus aureus are a growing problem for healthcare systems. Implant materials that resist bacterial colonization may help reduce infection rates and severity. This research examined the effect of a copper-coated carbon-infiltrated carbon nanotube surface (Cu-CICNT). We have previously shown that CICNT without copper has an anti-biofilm effect, and copper has long been known to have anti-bacterial properties. Bacterial biofilms were grown in a droplet on the Cu-CICNT surface, and a control consisting of copper deposited on a relatively flat, non-nanotube-structured surface. The Cu-CICNT surface was highly effective at reducing biofilm formation, reducing recoverable S. aureus bacteria by 99.9999% in 12 hours (a 6.3-log reduction). This effect was confirmed in both a methicillin-resistant and a methicillin-sensitive isolate of S. aureus. The Cu-CICNT surface was also highly effective against Pseudomonas aeruginosa, resulting in a 6.9-log reduction in adherent bacteria. The Cu-CICNT surface was more effective at inhibiting biofilm formation than the flat copper-coated titanium, indicating a synergistic effect between the CICNT topography and copper. The concentration of copper ions in growth media was low after exposure to Cu-CICNT (6.2 ppm), and media with this amount of supplemented copper had only a small effect on biofilm reduction, as did conditioned media previously exposed to Cu-CICNT. Our findings suggest that the antibacterial effect is likely due to contact killing of bacteria on the textured copper surface.IMPORTANCEOrthopedic implants and devices are becoming increasingly common. Unfortunately, as their use increases, so does the prevalence of implant-associated infections. These infections are most commonly caused by the bacterium Staphylococcus aureus. S. aureus infections are particularly difficult to treat because they form biofilms resistant to antibiotics and the host immune system. In this research, we used a carbon nanotube-based surface combined with a thin film of copper to produce a surface coating that could be used on implants to prevent bacterial infection. The combination of the surface topography with the copper coating resulted in over a 6-log reduction in the number of adherent bacteria, preventing the formation of a bacterial biofilm. This reduction in adherent bacteria is likely due to the surface killing effects of the bacteria on contact. The potential applications of such a surface could help reduce infection burden, improve patient quality of life, and reduce stress on healthcare systems.

RevDate: 2025-07-10
CmpDate: 2025-07-08

Kumar D, Beles M, Saha A, et al (2025)

Global analysis of the Hfq-mediated RNA interactome discovers a MicA homolog that affects the cytotoxicity, biofilm formation, and resistance to complement of Bordetella pertussis.

Nucleic acids research, 53(13):.

Bordetella pertussis is a Gram-negative, strictly human re-emerging respiratory pathogen and the causative agent of whooping cough. The requirement of the RNA chaperone Hfq for the virulence of B. pertussis suggests that Hfq-dependent small regulatory RNAs (sRNAs) are involved in the virulence of this pathogen. To identify their potential mRNA targets, we applied a method combining experimental and computational approaches called RIL-seq. The majority of putative mRNA targets, including several virulence factors, interact with two sRNAs, CT_433 and CT_521, suggesting that these sRNAs may represent central riboregulatory nodes of B. pertussis. Furthermore, our data suggest that CT_532 sRNA can base pair with the 5'UTR region of ompA mRNA encoding outer membrane protein BP0943 (OmpA) and that CT_532, RNase III and Hfq are involved in the control of ompA expression. The CT_532 sRNA shares 60% identity with the E. coli sRNA MicA and its expression is also modulated by Hfq and stress conditions such as heat and cold shocks. Overall, these results suggest that CT_532 represents a MicA homolog. Importantly, the mutant lacking the first 22 nucleotides of CT_532 exhibits reduced cytotoxicity towards human macrophages and impaired biofilm production but increased resistance to complement compared to the wild type strain.

RevDate: 2025-07-09

Ullah S, Chen Y, Wu C, et al (2025)

Mechanistic insights and therapeutic innovations in engineered nanomaterial-driven disruption of biofilm dynamics.

RSC advances, 15(29):23187-23222.

Bacteria employ biofilm formation as a survival strategy, characterized by the self-assembly of cells into 3D architectures encapsulated in an extracellular polymeric substance (EPS) that results in reduced antibiotic efficacy, increased tolerance, and emergence of multidrug resistance phenotypes. To overcome this challenge, persistent efforts are directed toward developing cutting-edge approaches and agents that rejuvenate antibiotic efficacy, mitigate biofilm formation, and eradicate biofilm-associated bacterial infections. Within this framework, nanotechnology has emerged as a pivotal tool for developing innovative functional materials with tailored attributes, exhibiting substantial potential in addressing the global health challenge of antibiotic resistance and biofilm-associated infections. This updated review article provides a comprehensive overview, commencing with a thorough analysis of biofilm formation and its implications, followed by a critical evaluation of cutting-edge strategies derived from recent research advancements. Our discussion encompasses novel strategies, including traditional nanomaterials, micro-nanobubbles, multifunctional nanozyme-mimetic platforms, artificial phage-like structures, and sophisticated nano-microrobotic systems. Each strategy is assessed for its potential to effectively target biofilms, enhance antimicrobial penetration, and restore antibiotic susceptibility. We anticipate that this timely review will inform and inspire innovative research directions, focusing on the rational design and application of advanced nanomaterials for targeted biofilm modulation and efficacious treatment, thereby advancing healthcare solutions.

RevDate: 2025-07-09

Rosado-Rosa JM, JV Sweedler (2025)

Bacterial biofilm sample preparation for spatial metabolomics.

The Analyst [Epub ahead of print].

Spatial metabolomics using mass spectrometry imaging (MSI) has become an important approach to study the surface of biological systems. MSI can probe bacterial metabolic processes through the direct analysis of bacterial colonies. In this review, we explore recent advancements made for bacterial metabolomics of primary and secondary metabolites using MSI, focusing on improvements in agar-based sample preparation and the use of membranes for improved sample preparation. The application of derivatization agents on bacterial samples enhances select metabolite signals and can aid analyte identification. Implementing dual imaging or multi-omics techniques also aids in identifying analytes and elucidating metabolic pathways active during the host-microbe interactions. Finally, we explore improvements towards robust three-dimensional protocols for whole colony MSI analysis. These advances enhance MSI analysis of bacterial samples and pose promising avenues for future studies.

RevDate: 2025-07-08

Rahman MA, Akter S, Md Ashrafudoulla , et al (2025)

Biofilm-microplastic interactions in food safety: mechanisms, risks, and control strategies.

Critical reviews in food science and nutrition [Epub ahead of print].

The pervasive use of plastics in the food industry has led to significant microplastic contamination, heightening food safety concerns. Microplastics not only infiltrate food systems but also provide optimal substrates for biofilm formation due to their hydrophobic and rough surface properties, which enhance microbial attachment. These biofilm-microplastic complexes protect embedded bacteria from disinfection efforts and facilitate the dissemination of pathogens and antibiotic-resistance genes, posing substantial risks to human health. This review investigates the mechanisms of biofilm formation on various plastic materials and elucidates how these interactions contribute to antimicrobial resistance and contamination in food systems. It also evaluates preventive and remedial strategies, including the development of alternative packaging materials, advanced cleaning protocols, and detection techniques for monitoring biofilm-microplastic complexes. Understanding these interactions is crucial for developing targeted interventions to mitigate contamination risks and enhance food safety and security. By integrating recent findings and proposing innovative strategies, this review aims to guide future research and inform policy development, supporting safer and more sustainable food production practices.

RevDate: 2025-07-07
CmpDate: 2025-07-08

El-Bouseary MM, Eliwa D, Farghali MH, et al (2025)

Investigating the potential antibacterial, anti-biofilm, wound healing and anti-inflammatory activity of the extract of Aspergillus niger endophyte isolated from cucumber leaves: in vitro and in vivo study.

BMC microbiology, 25(1):420.

BACKGROUND: Endophytic fungi are a vast inventory of bioactive compounds, offering potent, cost-effective, renewable, and low-toxicity alternatives for therapeutic applications. The current investigation focused on the endophytic fungus Aspergillus niger, which was isolated for the first time from Cucumis sativus (cucumber) leaves and subjected to comprehensive evaluation, including anti-inflammatory, antibacterial, anti-biofilm, and in vitro wound healing potential. 18 S rRNA gene sequencing was utilized to identify A. niger after isolation, and the fungus was cultivated on Asian rice to produce fungal metabolites. The high-resolution liquid chromatography-mass spectrometry (LC-HRESI-MS/MS) was then used to elucidate its phytochemical profile.

RESULTS: Fingerprint compounds detected in the ethyl acetate of the endophyte A. niger (ANM) revealed 15 compounds that are mainly pyrones and quinones in nature, including citric acid, nigerasperone A, aspernigrin A, aspinonene, campyrone B, aurasperone F, and plastoquinone-3. The ANM showed a strong antibacterial activity against S. aureus clinical isolates (MIC values ranging from 32 to 512 µg/mL) and a significant reduction in biofilm formation, where the total number of biofilm producers, S. aureus isolates, decreased from 19 to 6 after treatment with ½ MIC of ANM. Furthermore, ANM-treated WI38 human fibroblast cells displayed a wound closure percentage of 99.68% ± 0.02 compared to 83.37% ± 0.05 for the control cells. Additionally, the ANM demonstrated potential in promoting wound healing, particularly in infected wounds, through its antimicrobial, anti-inflammatory, and tissue-regenerating properties.

CONCLUSIONS: These findings highlight A. niger as a valuable source of natural therapeutics. Additional research is needed to explore its key active components and potential side effects.

RevDate: 2025-07-07

Ma J, He Q, Lai L, et al (2025)

TMT-Based Quantitative Proteomics Analysis Reveals Inhibitory Mechanism of CD-g-CS against the Biofilm Formation of Staphylococcus xylosus.

Microbial pathogenesis pii:S0882-4010(25)00556-X [Epub ahead of print].

Chitosan-grafted β-cyclodextrin (CD-g-CS) serves as an excipient combining drug delivery capacity with antimicrobial activity. Previous studies have demonstrated that the CD-g-CS nanoformulations have significant inhibitory effects on bacterial biofilms, although the mechanism of action remains unclear. Consequently, the present study used tandem mass tag (TMT)-based quantitative proteomics coupled with quantitative PCR (qPCR) to investigate the mechanism underlying CD-g-CS-mediated inhibition of Staphylococcus xylosus (S. xylosus) biofilm formation at the protein level. The results showed that 903 proteins were identified to be altered in S. xylosus treated with CD-g-CS, of which 430 were down-regulated and 500 were up-regulated. Bioinformatics analysis revealed that these differentially expressed proteins (DEPs) have different molecular functions and are involved in different molecular pathways. CD-g-CS can affected the functional pathways of S. xylosus in terms of ribosomes, phosphotransferase system (PTS), tricarboxylic acid (TCA) cycle, and nitrate respiration. These pathways affected the stability and morphology of biofilms, which in turn interfere with biofilm formation. These results provide a critical excipients for future development of anti-biofilm pharmaceutical formulations, offering novel solutions to combat biofilm infections.

RevDate: 2025-07-07

Da Cruz Nizer WS, Adams ME, Allison KN, et al (2025)

Extracellular DNA enhances Pseudomonas aeruginosa biofilm resistance to sodium hypochlorite stress.

Canadian journal of microbiology [Epub ahead of print].

The opportunistic human pathogen Pseudomonas aeruginosa exhibits high pathogenicity and antimicrobial resistance, largely due to its ability to form robust biofilms. In addition to the exopolysaccharides Psl and Pel, extracellular DNA (eDNA) is an important matrix component in P. aeruginosa PAO1 biofilms. It has been shown previously that eDNA is involved in biofilm initiation and integrity as well as antibiotic resistance, however, it's involvement in resistance to oxidative stressors such as the widely used disinfectant sodium hypochlorite (NaOCl) is less explored. Here, we examined the function of eDNA in NaOCl resistance of P. aeruginosa PAO1 biofilms. Using different biofilm assays in combination with a PAO1 ∆pslA pelF double mutant, which lacks the exopolysaccharides Psl and Pel, and a Tn-bfmR mutant, which exhibits increased eDNA amounts in biofilms, we were able to show that eDNA contributes to NaOCl resistance in P. aeruginosa PAO1 biofilms, in particular when exopolysaccharides are absent. Interestingly, NaOCl was more effective after DNAse treatment against ∆pslA pelF biofilms. These findings indicate that the protective function of eDNA in biofilm resistance is matrix composition-dependent and becomes more pronounced in the absence of Psl and Pel.

RevDate: 2025-07-07

Palma CSD, Haller DJ, Tabor JJ, et al (2025)

Changes in Spo0A~P pulsing frequency control biofilm matrix deactivation.

PLoS computational biology, 21(7):e1013263 pii:PCOMPBIOL-D-25-00289 [Epub ahead of print].

Under starvation conditions, B. subtilis survives by differentiating into one of two cell types: biofilm matrix-producing cells or sporulating cells. These two cell-differentiation pathways are activated by the same phosphorylated transcription factor - Spo0A~P. Despite sharing the activation mechanism, these cell fates are mutually exclusive at the single-cell level. This decision has been shown to be controlled by the effects of growth rate on gene dosage and protein dilution in the biofilm matrix production network. In this work, we explore an alternative mechanism of growth rate-mediated control of this cell fate decision. Namely, using deterministic and stochastic modeling, we investigate how the growth-rate-dependent pulsing dynamics of Spo0A~P affect biofilm matrix deactivation and activation. Specifically, we show that the Spo0A~P pulsing frequency tunes the biofilm matrix deactivation and activation probability. Interestingly, we found that DNA replication is the cell cycle stage that most substantially contributes to the deactivation of biofilm matrix production. Finally, we report that the deactivation of biofilm matrix production is not primarily regulated by the effects of growth rate on gene dosage and protein dilution. Instead, it is driven by changes in the pulsing period of Spo0A~P. In summary, our findings elucidate another mechanism governing biofilm deactivation during the late stages of starvation, thereby advancing our understanding of how bacterial networks interpret dynamic transcriptional regulatory signals to control stress-response pathways.

RevDate: 2025-07-07

Huang Q, Shen X, Luo X, et al (2025)

Impact of intestinal bacteria on biofilm formation, motility, virulence, and gene expression in Vibrio parahaemolyticus.

Microbiology spectrum [Epub ahead of print].

Vibrio parahaemolyticus, a foodborne pathogen, is a leading cause of acute gastroenteritis in humans. In contrast, non-pathogenic Escherichia coli is a common commensal bacterium residing in the human gut. Despite their co-occurrence during infection, the interaction between these two species remains poorly understood. This study revealed that V. parahaemolyticus outcompetes E. coli under co-culture conditions, demonstrating superior growth efficiency and competitive dominance. Co-cultivation stimulated biofilm formation in both species, with E. coli culture supernatant specifically enhancing biofilm development in V. parahaemolyticus. Nevertheless, V. parahaemolyticus dominated mixed microbial colonies. Additionally, co-cultivation reduced V. parahaemolyticus cell adhesion and swimming motility but heightened its cytotoxicity. RNA-seq analysis identified 629 differentially expressed genes in co-cultured V. parahaemolyticus compared to monocultured cells, including 290 upregulated and 339 downregulated genes. Genes related to flagella and type III secretion system 1 were downregulated, while those for exopolysaccharides, type IV pili, and type VI secretion system 2 were upregulated. Notably, eight genes involved in c-di-GMP metabolism showed significant changes, with seven being upregulated. Additionally, 22 putative transcriptional regulators exhibited differential expression, indicating tightly coordinated gene expression during interspecies interactions. These findings illuminate the dynamic interplay between V. parahaemolyticus and gut commensals, providing insights into pathogen behavior in polymicrobial environments. This work lays the groundwork for future studies on gut microbiota-pathogen interactions and their implications for infectious disease mechanisms.IMPORTANCEThis study reveals critical insights into the interplay between the gut commensal bacterium E. coli and the foodborne pathogen V. parahaemolyticus, offering novel perspectives on how gut microbiota influence pathogen behavior. V. parahaemolyticus outcompetes E. coli in co-culture, highlighting its adaptability and potential to disrupt gut microbial balance during infection. The E. coli culture supernatant enhances V. parahaemolyticus biofilm formation. Co-cultivation reduces V. parahaemolyticus motility but increases cytotoxicity. RNA-seq analysis identified 629 differentially expressed genes, including those associated with downregulated flagellar/T3SS1 systems and upregulated exopolysaccharide/T6SS2 pathways. These findings advance our understanding of gut microbiota-pathogen dynamics and could inform strategies to mitigate V. parahaemolyticus infections by targeting interspecies signaling or virulence pathways.

RevDate: 2025-07-08

Radha R, Fawad A, Ravindran S, et al (2025)

Enhanced Antimicrobial and Biofilm-Disrupting Properties of Gallium-Doped Carbon Dots.

ACS omega, 10(25):27559-27574.

Antibiotic resistance continues to be a global health threat caused by microbial biofilms, yet carbon dots (CDs) offer a promising countermeasure. Doping CDs with metals or nonmetals further enhances their properties while maintaining biocompatibility. This work reports the sonochemical synthesis of gallium-boronic acid carbon dots (Ga-BACDs) under conditions (20 kHz, 2000 W, 60% amplitude, 60 °C, and 60 min), achieving significant gallium incorporation. Ultraviolet-visible and fluorescence analyses reveal characteristic CD absorbance peaks at 286 and 355 nm and strong emission at 397-400 nm. Fourier transform infrared spectral changes on Ga-BACDs suggest successful incorporation of gallium and confirm Ga-H/Ga-O-C (2000-2600 cm[-] [1]) and Ga-O/Ga-O-Ga (400-700 cm[-] [1]) vibrations. X-ray diffraction and Raman spectroscopy data indicate the retention of the amorphous carbon framework with enhanced local ordering. High-resolution scanning electron microscopy (HR-SEM) and high-resolution transmission electron microscopy images demonstrate morphological alterations compared to BACDs with a particle mean diameter of 8.6 ± 4.1 nm. The gallium doping in Ga-BACDs was quantified as 3.66 ppm by using inductively coupled plasma-atomic emission spectroscopy. X-ray photoelectron spectroscopy results indicated that Ga is chemically integrated inside the carbon dot framework. The zeta potential shifts from -32.5 mV (BACDs) to -23.3 mV (Ga-BACDs), evidencing surface charge modulation. The antimicrobial activity of Ga-BACDs was tested against Gram-positive () and Gram-negative () bacterial strains; the presence of gallium contributed to improved bioactivity at 37 °C. HR-SEM images of Ga-BACD-treated bacteria presented significant structural damage, membrane rupture, and surface irregularities. Ga-BACDs inhibited biofilm formation at concentrations as low as 2.5 mg/mL and efficiently eradicated preformed biofilms, highlighting their promise for preventing biofilm-associated infections. MTT assays on normal human brain cells confirm the biocompatibility of Ga-BACD-coated cellulose discs and CD solution (0.1 mg/mL), supporting the safe use of Ga-BACD-modified fibers. Overall, our findings highlight Ga-BACDs as metal-doped carbon nanoparticles, with strong potential for novel antibacterial treatments.

RevDate: 2025-07-08

Kyei L, Campbell R, Menegatti C, et al (2025)

The Nobilamides: Potent Biofilm Inhibitors Produced by the Microbiota of Moon Snail Egg Masses.

ACS omega, 10(25):26791-26798.

Bacterial biofilm infections have become increasingly challenging to treat as bacteria living in a biofilm state are more resistant to antibiotics and protected from the host immune response. Eradicating biofilm infections generally requires treatment with high doses of antibiotics for prolonged periods; however, the rise in antibiotic resistance further challenges these treatments. Unfortunately, there are no approved drugs that inhibit or disrupt biofilm formation. Here, we leveraged our library of bacteria associated with moon snail egg masses found in Puerto Rico, using mass spectrometry-based metabolomics, to discover biofilm inhibitors. Analysis of a chemical fraction library revealed a set of peptides in fractions exhibiting potent inhibition of biofilms. Bioassay-guided isolation led to the isolation of lipopeptides, the nobilamides, which were previously shown to possess antibacterial activity and TRPV1 antagonist properties but were never evaluated in a biofilm inhibition assay. A thorough evaluation of the biofilm inhibition activity of A-3302-B and A-3302-A revealed they potently inhibit biofilm formation with IC50 of 161 ± 85 and 598 ± 66 nM, respectively. Interestingly, nobilamide A and B, linear analogs, are 500-fold less active than their cyclic analogs.

RevDate: 2025-07-08
CmpDate: 2025-07-07

Jemel I, Krayem N, Jlidi H, et al (2025)

Structural insights and biomedical potential of biosynthesized silver nanoparticles: antibacterial activity, anti-biofilm and cancer cell inhibition.

PeerJ, 13:e19608.

BACKGROUND: The increasing threat of antimicrobial resistance and cancer has driven the search for new therapeutic agents, with plant-based biosynthesis of nanoparticles emerging as a promising approach. Silver nanoparticles (AgNPs) synthesized from plant extracts have gained attention for their potential biomedical applications.

OBJECTIVE: This study aimed to synthesize, characterize, and evaluate the antimicrobial, anti-biofilm, and anticancer properties of AgNPs derived from Teucrium polium (Tp), Teucrium marum (Tm), and Punica granatum (Pg).

METHODS: AgNPs were synthesized using plant extracts and characterized by X-ray diffraction (XRD), dynamic light scattering (DLS), UV spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Antibacterial activity was assessed against Gram-negative and Gram-positive bacteria. The anti-biofilm efficacy was tested against Staphylococcus aureus and Pseudomonas aeruginosa. Cytotoxicity was evaluated on MCF-7 breast cancer cells.

RESULTS: XRD confirmed the face-centered cubic (fcc) crystal structure of AgNPs, with peaks at (111), (200), (220), and (311) planes. Crystallite sizes were smaller than their hydrodynamic diameters, suggesting surface modifications affecting DLS measurements. DLS analysis indicated monodisperse size distributions for Tp-AgNPs and Tm-AgNPs, while Pg-AgNPs showed a broader range. The biosynthesized silver AgNPs from different plants exhibit unique physicochemical properties, as evidenced by their distinct UV-vis absorption spectra, and show potential for optical and optoelectronic applications. FTIR spectroscopy analysis confirmed the presence of specific functional groups on the surface of biosynthesized AgNPs, indicating the role of plant extracts as reducing and capping agents, and revealed variations in binding sites and molecular interactions. Among the synthesized nanoparticles, Tp-AgNPs exhibited the highest antibacterial efficacy, particularly against Staphylococcus epidermis and Pseudomonas aeruginosa, though slightly less potent than chloramphenicol. Tp-AgNPs also showed the strongest inhibition of biofilm formation, followed by Tm-AgNPs, with Pg-AgNPs being the least effective. Cytotoxicity assays demonstrated that Tm-AgNPs had the highest anticancer activity against MCF-7 cells, with Tp-AgNPs exhibiting comparable effects.

CONCLUSION: The findings underscored the potent antimicrobial, anti-biofilm, and anticancer properties of Tp-AgNPs and Tm-AgNPs, making them promising candidates for biomedical applications. Further studies are needed to assess their clinical safety and therapeutic potential.

RevDate: 2025-07-08

Doan TM, Vu CTB, Truong PTL, et al (2025)

Analysis of the Mechanical and Biofilm-Inhibitory Antimicrobial Properties of a Dental Tissue Conditioner Incorporating Ocimum Gratissimum Essential Oil: An In Vitro Study.

International journal of dentistry, 2025:9994172.

Objectives: This study aimed to investigate the tensile bond strength (TBS) and biofilm-inhibitory antimicrobial properties of tissue conditioners combined with Ocimum gratissimum essential oil (EO) at varying concentrations. Materials and Methods: The original tissue conditioner was used as the control, while the experimental groups consisted of tissue conditioners incorporating O. gratissimum EO at concentrations of 1% and 2% (v/v) in the liquid component. The TBS between the tissue conditioner and denture base acrylic resin was measured using a universal testing machine. To evaluate biofilm-inhibitory antimicrobial properties, cylindrical specimens infused with EO were prepared and incubated with Candida albicans and Streptococcus mutans. The crystal violet assay was utilized to quantify microbial biofilm formation. Results: The incorporation of O. gratissimum EO into tissue conditioners significantly increased the TBS on day 1 (p < 0.05) but showed no effect by day 7 post-polymerization (p > 0.05). Additionally, tissue conditioners containing 1% EO exhibited biofilm-inhibitory antimicrobial properties on day 1 (p < 0.05), whereas those with 2% EO demonstrated biofilm-inhibitory antimicrobial activity on both days 1 and 3 postinoculation (p < 0.05). By day 5 and 7, EO-infused tissue conditioners no longer exhibited biofilm-inhibitory antimicrobial properties (p > 0.05). Conclusion: Tissue conditioners infused with O. gratissimum EO effectively reduced the formation of biofilms by C. albicans and S. mutans in a dose-dependent manner on days 1 and 3. As tissue conditioners are typically replaced every 3-7 days, O. gratissimum EO can be incorporated as an additive to lower the formation of biofilms by C. albicans and S. mutans without compromising the TBS of the tissue conditioner to denture base acrylic resin.

RevDate: 2025-07-08

Wang S, Song X, Zheng X, et al (2025)

FliA regulates the antibacterial activity of plantaricin BM-1 against Escherichia coli K-12 through the LuxS/AI-2 quorum-sensing-mediated biofilm formation.

Frontiers in microbiology, 16:1606567.

INTRODUCTION: Plantaricin BM-1 is a class IIa bacteriocin active against Escherichia coli. However, the mode of action of class IIa bacteriocins against gram-negative bacteria remains unclear. In this study, the regulatory role of sigma factor FliA (σ[28]) in the antibacterial mechanism of plantaricin BM-1 against E. coli K-12 BW25113 is evaluated.

METHODS: The fliA-complemented strain of E. coli JW1907, namely E. coli ReJW1907, was constructed through λ-Red homologous recombination. The effects of plantaricin BM-1 on E. coli growth, cell morphology, and membrane integrity were investigated using growth curves, electron microscopy, and flow cytometry. The biofilm formation ability of E. coli was evaluated using crystal violet staining and confocal laser scanning microscopy. Transcriptomic analysis was performed to screen for differentially expressed genes (DEGs).

RESULTS AND DISCUSSION: The inhibition rate (I%) of plantaricin BM-1 (3.75 mg/mL) against E. coli JW1907 (89.22 ± 1.13%) at the 8th h of culture was significantly higher than that of E. coli BW25113 (70.36 ± 6.30%) and ReJW1907 (74.75 ± 4.99%). The biofilm biomass produced by E. coli BW25113 (OD595 nm = 0.343 ± 0.056) was significantly reduced to 0.227 ± 0.04 after fliA deletion, and was recovered to its original level (0.358 ± 0.027) after fliA complement. A total of 205 DEGs were identified between E. coli BW25113 and JW1907. Among these, four DEGs (fliZ,wza, lsrR, and pgaA) were enriched in the biofilm formation pathway. Further analysis revealed eight up-regulated DEGs (lsrKRBDCAFG), which were significantly enriched in the LuxS/AI-2 quorum sensing (QS) system. After the deletion of any gene from lsrKRBDCAFG, the I% of plantaricin BM-1 against E. coli BW25113 (70.77 ± 7.01%) was significantly increased to 80.68-90.06%, with its biofilm production (0.254 ± 0.014) reduced to 0.135-0.188. In conclusion, FliA modulates biofilm formation through the LuxS/AI-2 QS system, thereby regulating the antibacterial activity of plantaricin BM-1. Overall, these findings improve our understanding of the bacteriostatic mechanism of class IIa bacteriocins against gram-negative bacteria.

RevDate: 2025-07-07

Chaudhary PK, Saini D, Srivastava AK, et al (2025)

Assessment of antifungal and anti-biofilm potential of essential oil active constituents alone and in combinatorial mode of limonene and linalool against Candida albicans and Candida tropicalis.

Natural product research [Epub ahead of print].

Opportunistic Candidiasis is rising among immunocompromised and elderly patients, with increasing antifungal resistance. This study evaluated five essential oil-derived compounds against Candida albicans and Candida tropicalis. Limonene showed the strongest antifungal activity, with minimum inhibitory concentration (MICs) of 32-64 µg/mL. Similarly, biofilm inhibition/eradication concentration (BIC/BEC) was found in followed the order: limonene > linalool > 1,8-cineole = 2-undecanone = borneol. Notably, the combination of limonene and linalool showed additive effects, with fractional inhibitory concentration index (FICI) values of 0.79 for C. albicans and 0.98 for C. tropicalis. This combinatorial approach, investigated for the first time, showed no significant cytotoxicity on human embryonic kidney (HEK-293) and human keratinocyte (HaCaT) cell lines. A co-culture model of Candida spp. and HaCaT cells was developed to study host-pathogen interactions and antifungal efficacy. Results highlight EO-ACs, especially limonene and linalool, as promising alternatives against resistant Candida infections.

RevDate: 2025-07-08
CmpDate: 2025-07-07

Deshmukh-Reeves E, Shaw M, Bilsby C, et al (2025)

Biofilm Formation on Endotracheal and Tracheostomy Tubing: A Systematic Review and Meta-Analysis of Culture Data and Sampling Method.

MicrobiologyOpen, 14(4):e70032.

Biofilm formation on tracheal tubing is a key risk factor for ventilator-associated pneumonia. Endotracheal tube microbiology has been systematically reviewed, but tracheostomy tube profiles have not. Analysis of the tube-associated microbiome is not standardised, and sampling methods are varied. We compared the reported microbiomes of endotracheal and tracheostomy tubes and examined the impact of sampling by tracheal aspiration or direct culture. We searched PubMed, SCOPUS, and Web of Knowledge for clinical microbiology studies from 2000-2024, extracting tubing type, sampling method, and the most prevalent genera identified. Genera were compared by Spearman's rank correlation and pairwise analyses by Šidák's test. Extraction from 49 studies identified 30 genera. Pseudomonas was the most prevalent in all conditions followed by Klebsiella, Staphylococcus, and Acinetobacter. 25 studies performed tracheal aspiration, and 22, direct culture. Two studies used both methods. Correlation was observed between endotracheal and tracheostomy tubes, and aspirates and direct cultures (Spearman's rho = 0.69; 0.59). Pseudomonas were more prevalent in tracheostomy tubes (p < 0.0001). Coagulase-positive Staphylococci were more common in tracheal aspirates, and coagulase-negative Staphylococci in direct culture. The microbial profiles of endotracheal and tracheostomy tubes are comparable, with Pseudomonas being the most common coloniser. Our analyses suggest that tracheal aspiration can effectively identify the constituents of biofilms without requiring tube removal, making it a valuable tool for clinical researchers to analyse or monitor biofilms before extubation or device failure using existing microbiology procedures.

RevDate: 2025-07-07

Jiang Q, Huang Y, Xu B, et al (2025)

Engineering Injectable, Adhesive, and Drug-Free Hydrogel for Efficient Acute Otitis Media Treatment by Biofilm Disruption and Immune Modulation.

Advanced healthcare materials [Epub ahead of print].

Acute otitis media (AOM) is a prevalent pediatric bacterial infection that is conventionally managed with prolonged oral antibiotic regimens. However, the therapeutic efficacy of this approach is increasingly compromised by the emergence of antibiotic resistance and bacterial biofilms. This study presents a novel multifunctional hydrogel, synthesized through the cross-linking of quaternary chitosan (QCS) with protocatechualdehyde (PA), to address these challenges. The QCS-PA hydrogel exhibits robust antibacterial activity against Escherichia coli and Staphylococcus aureus (S. aureus), effectively disrupting bacterial membranes and biofilms in vitro. For the in vivo studies using S. aureus-induced and lipopolysaccharides (LPS)-induced AOM animal models, the hydrogel significantly reduces bacterial burden within middle ear fluid and disrupts biofilms adhering to the middle ear mucosa. A single intratympanic administration of the hydrogel further demonstrates pronounced anti-inflammatory and immunomodulatory effects, evidenced by the suppression of inflammatory cell infiltration, the downregulation of pro-inflammatory cytokines levels, and the polarization of macrophages from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Transcriptome analyses reveal the downregulation of key inflammatory genes and associated signaling pathways, especially interleukin 17 (IL-17)-mediated inflammation signaling. Collectively, these findings establish the specific QCS-PA hydrogel as an efficient drug-free biomaterial for AOM therapy, offering multifunctional biofilm disruption and immune modulation without reliance on conventional antibiotics.

RevDate: 2025-07-07

Asokan-Sheeja H, Das D, Nguyen JN, et al (2025)

pH-Responsive Peptide-Polymer Hydrogel for Biofilm Disruption.

ACS applied bio materials [Epub ahead of print].

Biofilm formation presents a significant challenge in chronic infections as it enables bacteria to resist conventional antibiotics and thrive in various areas of the body. The treatment is further hurdled by the acidic environment of biofilms due to anaerobic glycolysis of bacteria and the accumulation of acidic byproducts. Therefore, there is a need for the development of antimicrobial materials that can selectively and preferentially eradicate biofilms in the acidic environment. Toward this aim, this study explores the use of acid-responsive double-network peptide-polymer hydrogels encapsulated with antimicrobial peptides to effectively target and disrupt biofilms. The hydrogel consists of two essential components: a self-assembling peptide nanofiber containing a non-natural ionic amino acid, which imparts pH responsiveness in the weakly acidic range, and a 4-arm PEG polymer that forms covalent bonds with the peptide nanofiber, enhancing the hydrogel's mechanical strength. Upon acidification, peptide nanofibers disassemble, causing an increased pore size of the hydrogel and release of encapsulated antimicrobials to the biofilm site. We expect that, by leveraging the unique properties of the double network self-assembled peptide-PEG hydrogels and the pH-triggered release mechanism, this innovative hydrogel approach may offer a more targeted, effective, and safer treatment option against biofilm-associated infections.

RevDate: 2025-07-06

Wang T, Song Y, Xu H, et al (2025)

Corrigendum to "Study on the mechanism of reducing biofilm toxicity and increasing antioxidant activity in vinegar processing phytomedicines containing pentacyclic triterpenoid saponins" [J. Ethnopharmacol. 290 (2022) 115112].

RevDate: 2025-07-06

Li W, Fan Y, Zhu W, et al (2025)

CsrR modulates biofilm formation of ST-17 GBS through the regulation of a novel adhesion factor, BapB.

Microbial pathogenesis pii:S0882-4010(25)00598-4 [Epub ahead of print].

INTRODUCTION: The hypervirulent ST-17 clone of Group B Streptococcus (GBS) is a leading cause of neonatal invasive meningitis. The link between GBS biofilm formation and the ST-17 lineage is established, and the inhibition of GBS biofilm formation by CsrR involves the regulation of adhesins. However, the specific adhesins involved in biofilm formation in ST-17 GBS strains are unknown.

HYPOTHESIS/GAP STATEMENT: CsrR inhibits biofilm formation of ST-17 GBS through the regulation of specific adhesins.

AIMS: To identify the adhesins contributing to biofilm formation in the ST-17 lineage.

METHODOLOGY: Comparative proteomics analyses of a strong biofilm-forming ST-17 strain and its csrR deletion mutant (ΔcsrR) were performed to identify the specific proteins involved in biofilm formation in ST-17 GBS. qPCR and biofilm formation assays were used to validate the proteomics analysis.

RESULTS: A novel biofilm-associated protein, BapB, absent in non-biofilm-forming ST-17 GBS strains (e.g., COH1), was identified. Biofilm production was significantly attenuated in the bapB deletion mutant (ΔbapB), reducing GBS adherence to fibronectin and laminin.

CONCLUSION: BapB plays a crucial role in biofilm formation. It may be a potential target for design of new therapeutic approaches against GBS.

RevDate: 2025-07-06

Chen C, Wang S, Niu W, et al (2025)

Synergistic effects of borneol and zwitterionic coating on enhanced antimicrobial and anti-biofilm performance.

Colloids and surfaces. B, Biointerfaces, 255:114929 pii:S0927-7765(25)00436-9 [Epub ahead of print].

Infections caused by microorganisms on the surfaces of medical implants and devices represent a significant challenge in the field of medicine. At present, a considerable number of antimicrobial coatings have been developed with the objective of preventing bacterial contamination. However, the problem of mold contamination is often underestimated. To address this issue, a bi-molecular composite coating was developed using sulfobetaine and borneol unites, which enabled the modification of polydimethylsiloxane (PDMS) substrates. Furthermore, by modifying the ratio of sulfobetaine and borneol groups, the coating can simultaneously demonstrate anti-bacterial, anti-mold adhesion and anti-biofilm properties. Notably, the bi-molecular polymer coating exhibited a synergistic effect in inhibiting bacterial biofilm formation. Subsequent in vivo subcutaneous implantation in mice confirmed its favorable biocompatibility. Therefore, this approach offers novel insights into the development of antimicrobial adhesion coatings for medical device surfaces, particularly those need to prevent biofilm formation.

RevDate: 2025-07-05

Lu H, Chen L, Liu J, et al (2025)

Periphytic biofilm (PB) in paddy field: A natural cadmium barrier for rice (Oryza sativa L.) safe production through physiological detoxification and gene regulation.

Journal of hazardous materials, 495:139136 pii:S0304-3894(25)02052-7 [Epub ahead of print].

Periphytic biofilm (PB) is ubiquitous in paddy fields and has significant impacts on the behavior of cadmium at the soil-water interface. However, its effects on rice growth and Cd accumulation remain largely unknown. Here, we conducted pot and field experiments to explore how PB affects rice growth and Cd migration pathways. Results showed that PB promoted rice growth and alleviated the toxic effects to rice in Cd-polluted soil, reducing Cd accumulation in rice shoot, root, and grain under both pot and field trials. PB treatment reduced the activities of antioxidant enzymes, particularly superoxide dismutase in rice leaves, which indicated less Cd-induced damage in rice leaves. Furthermore, PB enhanced the formation of iron/ manganese plaque around rice roots by 21-34 % under Cd-polluted soil, and increased the nitrogen and phosphorus uptake of rice root significantly. These were further verified by transcriptomic analyses that the expression of Cd-uptake associated genes such as OsCDT9, LCT, and HMA5 of rice plants in PB treatment was down-regulated, while nutrient uptake-related genes including OsISC12, OsGLU, and OsHAK7 were up-regulated. This study not only expands our understanding of Cd biogeochemistry in paddy ecosystem, but also provides a promising in situ approach to reducing Cd migration from soil to rice grain.

RevDate: 2025-07-05

Alsanea A, Bounaga A, Lyamlouli K, et al (2025)

Sulfate Reduction in the Hydrogen-Based Membrane Biofilm Reactor Receiving Calcium Reduced Phosphogypsum Water.

Biotechnology and bioengineering [Epub ahead of print].

Phosphogypsum (PG), a byproduct of phosphate mining, contains sulfate that can be leached and converted to elemental sulfur, thus offering a sustainable opportunity to recover sulfur (S) as a step toward a circular economy. Calcium, at ~15 mM in PG leachate, creates inorganic precipitation that interferes with biological sulfate reduction, the first step of S recovery. Here, we evaluated the effectiveness of using cation-exchange to lower the calcium concentration in water-leached PG (PG water) delivered to a H2-based membrane biofilm reactor (H2-MBfR) employed to reduce sulfate to sulfide. A high sulfate flux (1 gS/m[2]-day) and 65% sulfate reduction were achieved despite a high pH (10) resulting from base production during sulfate reduction. However, soluble sulfide was only 20% of the reduced S, possibly due to precipitation of sulfide, iron, and phosphate, and alkalinity analysis revealed possible formation of polysulfides. Shallow metagenomics of the biofilm documented that Desulfomicrobium was the dominant sulfate-reducing bacterium, while Thauera, a mixotroph capable of sulfate reduction and sulfide oxidation, also was an important genus. The metagenomics also revealed the presence of methanogens and acetogens that competed for H2 and CO2. Although calcium removal from PG water improved sulfate reduction and reduced inorganic precipitation in the H2-MBfR, soluble sulfide generation must be improved by supplying sufficient CO2 to moderate pH increase due to sulfate reduction and by controlling the H2-delivery capacity to limit methanogens and acetogens.

RevDate: 2025-07-07
CmpDate: 2025-07-04

Halim B, Waturangi DE, A Yulandi (2025)

Control of biofilm from single and multispecies bacteria associated with food spoilage using metabolite of Streptomyces sp. KP110 and Pseudomonas fluorescens JB 3B.

Scientific reports, 15(1):23956.

Food spoilage bacteria are responsible for food spoilage and often fabricate biofilms on various surfaces. Naturally, biofilms are constructed by multiple bacterial species. These biofilms are more difficult to control compared to single species biofilms. Effective multispecies biofilm treatments are necessary in the food industry. This research evaluated antibiofilm activities of Streptomyces sp. KP110 and Pseudomonas fluorescens JB 3B metabolites. Prior to this research, the two antibiofilm crude extracts had shown significant results against various single species biofilms, including Bacillus, Shewanella, Vibrio, etc. The crude extracts also showed quorum-quenching activities, further asserting the antibiofilm potential. This research further characterized these antibiofilm crude extracts against multispecies biofilms, as well as assessing the duration of biofilm formation inhibition. The food spoilage bacteria used in this study are Bacillus cereus, Bacillus subtilis, and Shewanella putrefaciens. Both crude extracts showed antibiofilm activities with better results against Gram-negative bacteria. The metabolites are also considered nontoxic, meaning they are potential candidates for industrial purposes. The dominant active compounds of Streptomyces sp. KP110 are ticlopidine and hexadecanoid acid, while Pseudomonas fluorescens JB 3B are phenol and indole.

RevDate: 2025-07-04

Ko BS, Park SG, MS Rhee (2025)

Synergistic antifungal effect of naturally-derived antimicrobials with penetration enhancer against Candida albicans biofilm at 5 °C and 22 °C.

Journal of infection and public health, 18(10):102882 pii:S1876-0341(25)00231-X [Epub ahead of print].

BACKGROUND: Biofilms of fungi such as Candida albicans (C. albicans) can survive even at cold temperatures and are generally difficult to eradicate with well-known antimicrobials. The aim of this study was to develop a novel synergistic technique against C. albicans biofilms using low concentrations of propylene glycol (PG), as a penetration enhancer. It helps naturally-derived antimicrobials [caprylic acid (CA) and carvacrol (CAR)] permeate C. albicans biofilms and cell membranes within short times even in cold environments.

METHODS: C. albicans biofilms formed on stainless steel coupons were treated with antifungal complexes (PG, CA and CAR at 0.6-1.2 mM) for 1 or 5 min at 5 and 22°C. PG was selected as the highest fungicidal efficacy, as well as its odourless, colourless nature and excellent solubility compared to other penetration enhancers (isopropyl citrate, laurocapram). To visualize cell damage by antifungal complex, treated biofilms at 5°C and 22°C were examined using the confocal microscopy and field emission scanning electron microscopy.

RESULTS: Each substance (PG, CA, CAR), when applied alone to C. albicans biofilms for 5 min, showed less than 0.50 log reduction at both 5 and 22°C. C. albicans biofilm was completely eradicated by PG + CA + CAR (all 1.2 mM) after 5 min at 5 and 22°C (> 6.20 log reduction), but treatment mixtures without PG were incompletely eliminated after 1 min at 5°C (1.75 log reduction) and 22°C (3.75 log reduction). Based on the visualization of biofilms, PG + CA + CAR (all 1.2 mM) resulted in remarkable membrane disruption and cell detachment from stainless steel coupons in contrast to the other treatment conditions.

CONCLUSION: This study indicates that trace amounts of developed antifungal complex could be an effective way to inactivate fungal biofilms on the surfaces of the medical and healthcare field even at cold temperatures.

RevDate: 2025-07-04

Mol Z, Waegenaar F, Pluym T, et al (2025)

Effect of biofilm, temperature and type of source water on the formation of haloanisoles in a pilot drinking water distribution system.

Water research, 285:124078 pii:S0043-1354(25)00986-8 [Epub ahead of print].

Taste and odor deviations in tap water affect many consumers and cause a preference for bottled water. However, since tap water is more sustainable than bottled water, these issues should be solved and prevented rapidly. Haloanisoles (HAs) have a very low odor threshold concentration (sub ng.L[-1]) and are of considerable concern since they are mainly formed in drinking water distribution systems (DWDS). Understanding their formation and influencing factors is a crucial aspect of addressing these odor problems. Therefore, this study uses a DWDS pilot to closely mimic the complex situation in real DWDS and investigates the (microbial) formation of six HAs regarding biofilm cell density and composition, temperature, and type of source water. Ten to thirty times higher formation was observed when a stable biofilm (5 months, 10 times more biomass) was present, compared to a young biofilm (2 weeks). With a spiked halophenol (HP) concentration of 0.1 mg.L[-1], the HA concentrations produced by a young biofilm were already within the OTC range. The mature biofilm contained a higher variety of HA-producing microorganisms and more O-methyltransferase genes to convert the precursors (HPs) into HAs. Higher temperatures (24 °C instead of 16 °C) increased the formation of each HA by a factor of 2 to 4, although still low HP-HA conversion ratios were observed (0.2 %). Regardless of the temperature and the type of source water, a clear pattern is observed in the type of HAs formed, with 2,3,4-trichloroanisole being the most abundant. This study finally investigated the effectiveness of flushing to mitigate these odorous compounds in DWDS and concludes that their partitioning between the biofilm and water phase affects the performance of flushing procedures.

RevDate: 2025-07-04

Lee CE, Messer LF, Wattiez R, et al (2025)

The invisible threats of sunscreen as a plastic co-pollutant: Impact of a common organic UV filter on biofilm formation and metabolic function in the nascent marine plastisphere.

Journal of hazardous materials, 495:139103 pii:S0304-3894(25)02019-9 [Epub ahead of print].

Plastic debris in marine environments serves as a substrate for microbial colonisation, forming biofilms known as 'plastispheres'. Also accumulated on plastic debris are co-pollutants including UV-protective organic UV-filters from sunscreens, which likely interact with this niche through their lipophilicity. Despite their widespread use and environmental accumulation, the influence of UV-filters on plastisphere composition and function has never been investigated. This study therefore investigates, for the first time, how co-pollution - specifically by an organic UV-filter - impacts the composition and function of marine plastisphere communities. To achieve this, low-density polyethylene (LDPE) was incubated with marine microbial communities for six days to cultivate a nascent plastisphere, which was then exposed to 5 mg/L of EthylHexyl MethoxyCinnamate (EHMC); the most used organic UV-filter in sunscreens, and a prevalent marine pollutant. Metagenomic analyses revealed that EHMC favoured the growth of bacterial generalists Pseudomonas and Psychromonas while reducing pollutant-degrading genera like Marinomonas. Analysis of 3070 proteins revealed a consistent upregulation of proteins used for biofilm maintenance by Pseudomonas with EHMC exposure, including the considerable upregulation of outer membrane porin F (OprF) which regulates exopolymeric substance (EPS) production. Additionally, proteins thought to indicate a shift from aerobic to anaerobic respiration were frequently expressed after exposure to EHMC. This may have selected against the obligate aerobes Marinomonas and Pseudoalteromonas, contributing to the observed shift in community composition. These findings underscore the importance of considering chemical co-pollutants in plastisphere research as we now begin to discover how ecologically significant, and potentially harmful microbial genera are affected by this interaction.

RevDate: 2025-07-05

Ansari M, Kazemi M, Mohammadi Sichani M, et al (2025)

The inhibitory effect of the methanolic extract and the essence of Anvillea garcinii on expression of the genes related to Staphylococcus aureus biofilm formation.

Iranian journal of microbiology, 17(3):470-479.

BACKGROUND AND OBJECTIVES: Staphylococcus aureus (S. aureus) is a pathogenic bacterium whose virulence is attributed to its extracellular compounds and biofilm-forming ability. This study aimed to evaluate the inhibitory effects of the methanolic extract (AGME) and the essential oil (AGEO) of Anvillea garcinii on the growth and the biofilm formation of S. aureus.

MATERIALS AND METHODS: The antibacterial and antibiofilm activities of AGME and AGEO against S. aureus ATCC 6538 were assessed using the microbroth dilution method and the Crystal Violet Staining Assay, respectively. The expression levels of sarA, spa, and icaA, genes involved in biofilm formation, were analyzed using real-time PCR.

RESULTS: AGME and AGEO inhibited S. aureus growth at minimum inhibitory concentrations (MIC) of 1 mg/ml and 0.6 mg/ml, respectively. AGME exhibited a 72% inhibition of biofilm formation at ¼ MIC, whereas AGEO showed no significant antibiofilm activity. AGME downregulated the expression of sarA, a key regulator of biofilm formation, as well as spa, and icaA genes.

CONCLUSION: This study demonstrated that A. garcinii essential oil (AGEO) exhibits significant antimicrobial activity, while its methanolic extract (AGME) effectively inhibits biofilm formation in S. aureus. These findings suggest the potential application of AGEO and AGME as antimicrobial and antibiofilm agents. Further investigations on their efficacy against other bacterial pathogens are recommended.

RevDate: 2025-07-05

Abed HS, Hosseini SM, ZM Jassim (2025)

Immunological and molecular detection of biofilm formation and antibiotic resistance genes of Pseudomonas aeruginosa isolated from urinary tract.

Iranian journal of microbiology, 17(3):376-381.

BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa (P. aeruginosa) is one of the most common causes of hospital-acquired infections. It is associated with high morbidity and healthcare costs, especially when appropriate antibiotic treatment is delayed. Antibiotic selection for patients with P. aeruginosa infections is challenging due to the bacteria's inherent resistance to many commercially available antibiotics. This study investigated antibiotic-resistance genes in isolated bacteria, which play a key role in disease pathogenesis.

MATERIALS AND METHODS: 100 samples out of the 140 samples collected from urinary tract infections (UTIs) cases between December 15[th], 2022, and April 15[th], 2023, were included in the study. Identification of bacterial isolates was based on colony morphology, microscopic examination, biochemical tests, and the Vitek-2 system. Antibiotic resistance genes; Aph(3)-llla, ParC, Tet/tet(M), and aac(6´)-Ib-cr were tested by polymerase chain reaction (PCR).

RESULTS: The obtained results were based on bacterial identifications of 81 clinical samples. Only 26 (32%) of these isolates were P. aeruginosa, 21 (26%) were Escherichia coli, and 18 (22.2%) were other bacteria. These isolates were used to detect four genes including tet(M), Aph(3)-llla, Par-c, and aac(6´)-Ib-cr. Four types of primers were used for PCR detection. The results showed that 11/14 (78.57%) carried the tet(M) gene, 10/14 (71.42%) carried the Aph(3)-llla gene, 14/14 (100%) carried the Par-c gene, and 10/14 (71.42%) of the isolates carried the aac(6´)-Ib-cr gene. The biofilm formation examining the esp gene, showed that 9 (64.28) isolates carried this gene.

CONCLUSION: The inability of antibiotics to penetrate biofilms is an important factor contributing to the antibiotic tolerance of bacterial biofilms.

RevDate: 2025-07-05

Jarzynka S, Koryszewska-Bagińska A, Nowikiewicz T, et al (2025)

Staphylococcus aureus nasal carriage before breast reconstruction: antibiotic resistance, biofilm formation, and virulence genes-a single center in vitro observation.

Frontiers in microbiology, 16:1610739.

INTRODUCTION: Infections caused by Staphylococcus aureus (S. aureus) in patients undergoing mastectomy followed by breast reconstruction present significant therapeutic challenges. Studies suggest that S. aureus may be transmitted from nasal carriage, potentially leading to postoperative infections. However, knowledge regarding the potential pathogenicity of S. aureus nasal carriage strains in women undergoing breast reconstruction in Poland remains limited. This study aimed to characterize S. aureus isolates obtained from screening nasal swabs.

METHODS: A total of 33 methicillin-sensitive S. aureus (MSSA) isolates were analyzed. These strains exhibited a high prevalence of genes encoding adhesion and antibiotic resistance. The most frequently detected virulence genes included sarA (100%), an activator of protein A; cna (100%), encoding collagen adhesin; blaZ (100%), associated with β-lactamase production; the icaADBC operon (82-100%), responsible for extracellular polysaccharide synthesis and intracellular adhesion; and bap (36%), encoding a surface-associated biofilm protein.

RESULTS: Most isolates (79-100%) demonstrated a strong capacity for biofilm formation and exopolysaccharide production, confirmed by independent methods. Notably, all strains (100%) remained susceptible to ciprofloxacin at increased exposure levels. RAPD analysis revealed low genetic diversity among the isolates.

DISCUSSION: Our findings indicate that S. aureus isolates from nasal carriers undergoing breast implantation exhibit antibiotic resistance, biofilm-forming ability, and harbor multiple virulence genes. Early detection of S. aureus colonization via nasal swab screening may be crucial for managing infection risk in patients undergoing breast reconstruction.

RevDate: 2025-07-05

Carstensen S, Suss PH, Ortis GB, et al (2025)

Transcriptional evaluation of functional genes of resistance, biofilm and quorum sensing in CTX-M15 ESBL-producing Klebsiella pneumoniae after meropenem concentration based on serum level.

Research in microbiology pii:S0923-2508(25)00039-7 [Epub ahead of print].

BACKGROUND: Klebsiella pneumoniae is a leading cause of multidrug-resistant hospital-acquired infections. Resistance to carbapenems, particularly meropenem, is increasingly reported and often linked to β-lactamase production, porin alterations, and efflux pump overexpression. However, the immediate transcriptional response of clinical isolates to meropenem remains poorly characterized.

AIM: To investigate the transcriptomic response of a CTX-M-15-producing K. pneumoniae clinical isolate to clinically relevant meropenem exposure and identify potential non-enzymatic resistance and survival mechanisms.

METHODS: A meropenem-susceptible K. pneumoniae isolate was recovered from a bacteremic patient and confirmed to carry CTX-M-15, SHV-182, and OXA-1 β-lactamase genes. Time-kill assays were performed using serum-level meropenem concentrations. RNA was extracted at multiple time points (0, 10, 30, and 60 min) post-exposure, followed by RNA-sequencing. Differential gene expression was analyzed using DESeq2. Resistance genes were identified via genome sequencing and annotated using CARD and VFDB databases.

RESULTS: Meropenem exhibited a concentration-dependent bactericidal effect, with full inhibition sustained only at serum-level concentrations. Transcriptomic analysis revealed significant upregulation of genes linked to biofilm formation (e.g., osmB, lipoproteins), efflux pumps (mepA, acrB), and cell wall remodeling (murJ, lpoB). No differential expression was observed for blaCTX-M-15, blaOXA-1, or blaSHV-182. The transcriptional regulator ompR was induced, suggesting membrane permeability adjustments.

CONCLUSION: K. pneumoniae rapidly activates adaptive stress responses under meropenem exposure, primarily through biofilm-related genes, efflux pumps, and membrane remodeling rather than increased β-lactamase expression. These findings underscore the complexity of antimicrobial tolerance mechanisms and may inform novel therapeutic strategies targeting transcriptional plasticity in multidrug-resistant pathogens.

RevDate: 2025-07-06
CmpDate: 2025-07-03

Cieślik M, Wójcicki M, Migdał P, et al (2025)

Fighting biofilm: bacteriophages eliminate biofilm formed by multidrug-resistant Enterobacter hormaechei on urological catheters.

Medical microbiology and immunology, 214(1):33.

The Enterobacter cloacae complex (ECC) is a prevalent nosocomial pathogen associated with various human infections, which currently comprises several species, including Enterobacter cloacae and Enterobacter hormaechei. Strains capable of producing biofilm on various biotic and abiotic surfaces pose a particular threat. Therefore, we focused on three E. hormaechei strains in whose genomes the presence of the biofilm-related genes: fimA, csgA, csgD, and sdiA was confirmed. Kinetic of biofilm formation by these strains on urological catheters depended on the catheter material (silicon or latex), temperature (24 °C or 37 °C) and incubation time. The ability of phages to disrupt biofilm formation was assessed and found to be the most effective when phages were applied at an early stages of this process. Moreover, destruction of existing biofilm by bacteriophages and/or silver or copper nanoparticles was strain-dependent. Incubation with Enterobacter-specific bacteriophages enabled, in some cases, almost complete eradication of three-day biofilms attached to urological catheters. In genomes of two Enterobacter-specific bacteriophages the presence of regions encoding proteins with lytic activity were identified (6 regions in Entb_43 phage and 4 regions in Entb_45 phage genomes, respectively). These results highlight the threat of biofilm-related infections, but also indicate the multifaceted anti-biofilm activity of bacteriophages, which should be considered for useful in clinical practice.

RevDate: 2025-07-03

Wei G, Palalay J-JS, Sanfilippo JE, et al (2025)

Flagellum-driven motility enhances Pseudomonas aeruginosa biofilm formation by altering cell orientation.

Applied and environmental microbiology [Epub ahead of print].

Bacterial motility plays a crucial role in biofilm development, yet the underlying mechanism remains not fully understood. Here, we demonstrate that the flagellum-driven motility of Pseudomonas aeruginosa enhances biofilm formation by altering the orientation of bacterial cells, an effect controlled by shear stress rather than shear rate. By tracking wild-type P. aeruginosa and its non-motile mutants in a microfluidic channel, we demonstrate that while non-motile cells align with the flow, many motile cells can orient toward the channel sidewalls, enhancing cell surface attachment and increasing biofilm cell density by up to 10-fold. Experiments with varying fluid viscosities further demonstrate that bacterial swimming speed decreases with increasing fluid viscosity, and the cell orientation scales with the shear stress rather than shear rate. Our results provide a quantitative framework to predict the role of motility in the orientation and biofilm development under different flow conditions and viscosities.IMPORTANCEBiofilms are ubiquitous in rivers, water pipes, and medical devices, impacting the environment and human health. While bacterial motility plays a crucial role in biofilm development, a mechanistic understanding remains limited, hindering our ability to predict and control biofilms. Here, we reveal how the motility of Pseudomonas aeruginosa, a common pathogen, influences biofilm formation through systematically controlled microfluidic experiments with confocal and high-speed microscopy. We demonstrate that the orientation of bacterial cells is controlled by shear stress. While non-motile cells primarily align with the flow, many motile cells overcome the fluid shear forces and reorient toward the channel sidewalls, increasing biofilm cell density by up to 10-fold. Our findings provide insights into how bacterial transition from free-swimming to surface-attached states under varying flow conditions, emphasizing the role of cell orientation in biofilm establishment. These results enhance our understanding of bacterial behavior in flow environments, informing strategies for biofilm management and control.

RevDate: 2025-07-04

Pan J, Albarrak A, Hicks J, et al (2025)

Influence of the ATP-dependent DNA ligase, Lig E, on Neisseria gonorrhoeae microcolony and biofilm formation.

Biofilm, 10:100292.

Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection, gonorrhoea, is known to form biofilms rich in extracellular DNA on human cervical cells. Biofilm formation is conducive to increased antimicrobial resistance and evasion of the host immune system, potentially causing asymptomatic infections. Using plate-based assays we have previously shown that disruption of a potential extracellular DNA ligase, Lig E, in N. gonorrhoeae impacts biofilm formation. In this research, we further explored this phenotype using confocal and scanning electron microscopy to directly visualise the morphology of microcolony and biofilm formation. Biofilm growth on artificial surfaces and on 3-dimensional human vaginal epithelial tissue was evaluated for strains where lig E was either disrupted or overexpressed. Results demonstrated that Lig E was important for the formation of robust, compact N. gonorrhoeae microcolonies, as well as extensive biofilms on artificial surfaces. The lig E deletion strain also had the highest tendency to be retained on the surface of epithelial tissues, with decreased invasion and damage to host cell layers. These findings support a role for Lig E to be secreted from N. gonorrhoeae cells for the purpose of inter-cell adhesion and biofilm formation. We suggest that Lig E strengthens the extracellular matrix and hence microcolony and biofilm formation of N. gonorrhoeae by ligation of extracellular DNA.

RevDate: 2025-07-04

Slater FC, Fish KE, JB Boxall (2025)

Similarity of drinking water biofilm microbiome despite diverse planktonic water community and quality.

Frontiers in microbiology, 16:1567992.

The impact of drinking water quality, in particular the planktonic microbiome, on the bacterial and fungal community composition of biofilms in drinking water infrastructure is explored. Understanding drinking water biofilms is critical as biofilms can degrade water quality and potentially present a public health risk if pathogens are released. Biofilms were developed for 12 months in three state-of-the-art pipe loop facilities installed at water treatment works and hence supplied by distinct treated drinking water and unique planktonic bacterial and fungal microbiomes. Each pipe loop had identical physical conditions, including pipe diameter, material and hydraulic regime (shear stress and turbulence). Despite the different bulk-waters, the bacterial and fungal community composition of the biofilm within each loop were remarkably similar, although in different quantities. The similarity between the biofilms from unique systems, with significantly different planktonic microbiomes, suggests shared selective pressures across the different sites which are independent of the varying water qualities, including planktonic community. This suggests that taking a global view of biofilm microbiome management is potentially feasible and that approaches controlling material or hydraulics may be best way to do this.

RevDate: 2025-07-03

Kensche A, Pohl C, Basche S, et al (2025)

Bovine milk and milk protein- promotor or inhibitor of bacterial biofilm formation at the tooth surface?.

BMC oral health, 25(1):992.

BACKGROUND: The present study aimed to investigate if mouthrinses with different types of bovine milk or milk protein isolates influence the initial bacterial colonization of the tooth surface.

METHODS: From 8 subjects, different biofilm samples were collected in situ on bovine enamel slabs: after 3 min of pellicle formation, mouthrinses with homogenized UHT-milk (0.3% and 3.5% fat), homogenized fresh milk (3.5% fat), non-homogenized milk 3.8%, 30% UHT-cream or a 3% micellar casein isolates containing preparation were performed, followed by a continued intraoral slab exposure for 8 h overnight. As control, no rinse was adopted. Afterwards, bacterial adhesion was quantified by DAPI staining and bacterial viability was determined by BacLight LIVE/DEAD-staining. Extracellular polysaccharides were visualized by Concanavalin A/Alexa-Fluor 594-staining. Statistical analysis was performed by the Kruskal-Wallis test and the Mann-Whitney U test followed by Bonferroni-Holm correction.

RESULTS: After 8 h of intraoral biofilm formation, 1.62*10[6]±1.68*10[6] bacteria/cm[2] were quantified in the control samples. Viability staining showed a distribution of 35% vital to 65% avital bacteria. None of the applied mouthrinses showed a significant change (p > 0.01) in bacterial colonization. A tendency to reduce bacterial colonization in situ was observed for non-homogenized milk and casein micelles.

CONCLUSION: Mouthrinsing with bovine milk and milk protein isolates had no significant impact on initial biofilm formation at the tooth surface. Clearly, it does not increase bacterial colonization.

RevDate: 2025-07-03

Tang Y, Deng H, Xu Z, et al (2025)

Repurposing AZD-5991 for inhibiting growth and biofilm formation of Staphylococcus aureus by disrupting the cell membrane and targeting FabI.

BMC microbiology, 25(1):393.

UNLABELLED: Staphylococcus aureus infections have emerged as a global public health threat. Two key factors—drug resistance and biofilm formation—substantially impair the efficacy of the antimicrobial treatment for S. aureus infections using conventional antibiotics. Consequently, discovering novel antimicrobial agents with potent antibacterial and antibiofilm activity has become a hotspot in recent years. Herein, the research first reported the remarkable inhibitory activity of AZD-5991, a selective Mcl-1 inhibitor, against S. aureus. The MIC50 and MIC90 values of AZD-5991 against S. aureus were 12.5 µM, and significant growth inhibition was observed at a subinhibitory concentration of 1/2 × MIC. Additionally, AZD-5991 exhibited bactericidal activity and a robust capacity for inhibiting S. aureus biofilm formation, with minimal cytotoxicity toward host cell lines. Membrane permeability assays revealed that AZD-5991 compromised S. aureus cell membrane integrity, while bacterial phospholipid components were found to neutralize the antibacterial activity of AZD-5991. Moreover, whole-genome sequencing and proteomic analysis were also applied to gain insights into the possible impact of AZD-5991 on the fatty metabolism of S. aureus. Furthermore, the antibacterial activity of AZD-5991 was remarkably declined by exogenous fatty acids linoleic acid (C18:2Δ9,12) and arachidonic acid (C20:4Δ5,8,11,14). Lastly, the biolayer interferometry assay supported the direct interaction of AZD-5991 with FabI, a key protein essential for bacterial growth and fatty acid metabolism. Conclusively, this study demonstrates that AZD-5991 inhibits S. aureus planktonic growth and biofilm formation by disrupting cell membrane integrity and targeting FabI. These findings position AZD-5991 as a promising novel antibiotic candidate for treating S. aureus infections resistant to traditional clinical antibiotics.

GRAPHICAL ABSTRACT: [Image: see text]

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12866-025-04104-2.

RevDate: 2025-07-03
CmpDate: 2025-07-03

Veisi M, Hosseini-Nave H, O Tadjrobehkar (2025)

Biofilm formation ability and swarming motility are associated with some virulence genes in Proteus mirabilis.

BMC microbiology, 25(1):388.

Proteus mirabilis (P. mirabilis) is one of the frequent causes of urinary tract infection in humans. This pathogen armed by diverse virulence associated factors. Biofilm formation and swarming motility are two surface living behaviors of P. mirabilis and their association with virulence associated genes was investigated in the present study. Biofilm formation ability and swarming motility were evaluated by microtiter plate assay and top-agar travel tracking in 91 P. mirabilis isolates respectively. The polymerase chain reaction method was used for screening of 10 virulence associated genes. Association of virulence associated genes with biofilm formation ability and also swarming motility was analyzed statistically. The zapA (100%) and hlyA (41.8%) genes had maximum and minimum frequency respectively. Forty-one, 35 and 15 isolates were categorized as weak, intermediate and strong biofilm producers respectively. While, 11%, 38.5% and 50.5% of isolates were grouped as weak, intermediate and strong swarmers respectively. Adhesin encoding genes such as mrpA were more prevalent in strong biofilm producers in comparison to the other isolates. Reversal association of rsmA gene with swarming motility was detected. The frequency of hlyA gene was associated directly with swarming motility and in opposite way with biofilm formation. Reverse correlation of biofilm formation ability and swarming motility was estimated. Based on the study findings it is hypothesized that P. mirabilis benefited from adhesins such as MR/P fimbriae for production of biofilm and successful colonization and then they shift from biofilm formers to strong swarmers in order to reach deeper urinary organs and HlyA toxin is used to overcome the immune system cells. However, it has to confirmed trough future studies.

RevDate: 2025-07-02

Hendricks AL, More KR, Devaraj A, et al (2025)

Author Correction: Bacterial biofilm-derived H-NS protein acts as a defense against Neutrophil Extracellular Traps (NETs).

NPJ biofilms and microbiomes, 11(1):126 pii:10.1038/s41522-025-00761-3.

RevDate: 2025-07-02

Prado A, Veiga FF, de Oliveira Brito R, et al (2025)

Biofilm formation efficiency by Candida species isolated from gastric mucosa of intragastric balloon patient under extremely low pH.

Folia microbiologica [Epub ahead of print].

This study characterized biofilms formed by Candida albicans and C. tropicalis isolated from the gastric mucosa biopsies of an intragastric balloon (IGB) patient user. Both were cultivated to form single and mixed artificial biofilms at pH 2.5 and 5.5 for 24 and 48 h. The biofilms were assessed for biochemical, metabolic, and ultrastructural properties. Yeast counts in monospecies C. albicans and C. tropicalis biofilms were higher than their respective levels in mixed biofilms across both pH values. Single C. tropicalis biofilms exhibited greater metabolic activity at both time points than C. albicans and mixed biofilms. While there were no notable pH or time-dependent differences in C. albicans and C. tropicalis monospecies biofilm formation, mixed biofilms displayed significantly higher biomass at pH 2.5. Ct also demonstrated pronounced filamentation within 24 h at pH 5.5. Scanning electron microscopy revealed cellular damage in mixed biofilms at pH 2.5; although, the biofilm structure was well developed within 24-48 h. Our findings indicate that yeasts isolated from IGB patients can form mono and polymicrobial biofilms under harsh conditions, with both species demonstrating biofilm viability at pH 2.5. Notably, C. tropicalis exhibited increased competitiveness in mixed biofilms under these conditions.

RevDate: 2025-07-04
CmpDate: 2025-07-03

Kushwaha M, Dalal N, Chaudhary S, et al (2025)

Colorectal cancer biofilm composition reveals distinct bacterial species signature.

Applied microbiology and biotechnology, 109(1):159.

Human colon hosts a highly organized protective microbial ecosystem in the form of biofilms, increasingly recognized as key contributors to colorectal cancer (CRC) progression through microbial dysbiosis and complex host-microbiota interactions. In India, CRC ranks among the top ten cancers, with an age-standardized incidence rate of approximately 6.3 per 100,000 in males and 3.7 per 100,000 in females highlighting a higher risk in men, late-stage diagnosis, inadequate screening, and treatment limitations, particularly in urban populations. This study aims to explore the microbial composition of colonic biofilms from the Indian cohort of colorectal cancer patients from New Delhi, which is witnessing a rise in the incidence of CRC. Colorectal biopsies were taken from tumors (n = 15) and adjacent non-tumor tissues (n = 15) at the Gastrointestinal Department of AIIMS, New Delhi, India. Fluorescence in situ hybridization (FISH) was employed to determine the bacterial population in the biofilm. The workflow included microtomy, deparaffinization, tissue permeabilization, and hybridization with bacterial 16S rDNA probes, and the detected signals were visualized by confocal microscopy. The results showed quite different microbial patterns and tumor-associated biofilms were found to have an increased density of Escherichia coli, Klebsiella pneumoniae, and Bacteroides fragilis, while Fusobacterium nucleatum and E. coli (pks[+]) with a pks[+] genomic island encoding the genotoxin colibactin were seen less often. These results confirm significant dysbiosis and the formation of invasive biofilms in CRC tissues. Understanding the composition of these biofilms may facilitate the development of targeted strategies to restore microbial balance and reduce CRC risk both in the Indian and global population. KEY POINTS: • Tumor-associated biofilms show distinct microbial dysbiosis in Indian CRC patients. • Enrichment of Escherichia coli, Klebsiella pneumoniae, and Bacteroides fragilis was observed at tumor site. • Insights into biofilm composition may aid to targeted interventions for CRC risk reduction.

RevDate: 2025-07-04
CmpDate: 2025-07-02

Xia M, Cao S, Liu Z, et al (2025)

Multifunctional nano-delivery system based on DNase I and photodynamic therapy for combatting enterococcus faecalis biofilm infections.

Scientific reports, 15(1):23343.

Persistent or refractory apical periodontitis is primarily caused by microbial retention, as conventional root canal treatment often fails to eliminate infections completely, and systemic antibiotic therapy is insufficient to achieve effective concentrations for eradicating bacterial biofilms within root canals. This highlights the urgent need for novel therapeutics offering safe and effective antimicrobial strategies. Antimicrobial photodynamic therapy (aPDT) is a promising approach for root canal disinfection. However, commonly used photosensitizers such as Ce6 suffer from poor water solubility and strong aggregation tendencies, resulting in limited penetration into infected sites. In this study, we developed a DNase I-Lip@Ce6 nanodelivery system by combining deoxyribonuclease I (DNase I) with liposome-encapsulated Ce6. The liposomal carrier facilitated efficient delivery of Ce6 into target bacterial cells, while DNase I degraded extracellular DNA in the biofilm matrix, weakening its protective barrier. This synergistically enhanced Ce6 penetration and therapeutic efficacy, leading to the successful eradication of planktonic Enterococcus faecalis and in vitro biofilms. This strategy offers a novel approach for the precision treatment of persistent oral infections and holds strong potential for clinical translation.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Wang L, Zhuo W, He T, et al (2025)

Insights into microbial actions on hydraulic concrete structures: Effects of ammonia and sulfate on community structure, function and biofilm morphology.

Journal of environmental sciences (China), 157:430-442.

Microbial corrosion of hydraulic concrete structures (HCSs) has received increasing research concerns. However, knowledge on the morphology of attached biofilms, as well as the community structures and functions cultivated under variable nutrient levels is lacking. Here, biofilm colonization patterns and community structures responding to variable levels of ammonia and sulfate were explored. From field sampling, NH4[+]-N was proven key factor governing community structure in attached biofilms, verifying the reliability of selecting target nutrient species in batch experiments. Biofilms exhibited significant compositional differences in field sampling and incubation experiments. As the nutrient increased in batch experiments, the growth of biofilms gradually slowed down and uneven distribution was detected. The proportions of proteins and β-d-glucose polysaccharides in biofilms experienced a decrease in response to elevated levels of nutrients. With the increased of nutrients, the mass losses of concretes exhibited an increase, reaching a highest value of 2.37 % in the presence of 20 mg/L of ammonia. Microbial communities underwent a significant transition in structure and metabolic functions to ammonia gradient. The highest activity of nitrification was observed in biofilms colonized in the presence of 20 mg/L of ammonia. While the communities and their functions remained relatively more stable responding to sulfate gradient. Our research provides novel insights into the structures of biofilms attached on HCSs and the metabolic functions in the presence of high level of nutrients, which is of significance for the operation and maintenance of hydraulic engineering structures.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Wu X, Jin C, Zhang C, et al (2025)

Mixotrophic Chlorella pyrenoidosa biofilm with enhanced biomass production, microalgal activity, and nutrient removal from nutrient-rich wastewater.

Journal of environmental sciences (China), 157:366-377.

Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-rich wastewater that are highly efficient and independent of the C/N ratio. However, challenges such as low biomass productivity, high variability in nutrient removal under different trophic types, and difficulty in harvesting biomass limits the large-scale application of microalgae wastewater treatment. This study attempted to employ mixotrophic microalgae biofilm to address these issues. The biomass production, microalgal activity, and nutrient removal of Chlorella pyrenoidosa biofilms with different trophic types were compared for nutrient-rich wastewater treatment. The results showed that the biomass productivity of the mixotrophic microalgal biofilm (0.215 g/(L·d)) was 2.3, 8.6, and 6.0 times higher than that of photoautotrophic microalgal biofilm, heterotrophic microalgal biofilm, and photoautotrophic suspended microalga, respectively. Additionally, the dehydrogenase activity (DHA), indicating microalgal activity, of the mixotrophic biofilm was 2.3 and 16.5 times higher than that of photoautotrophic and heterotrophic biofilms, respectively. Meanwhile, the mixotrophic biofilm removed 96.0 % of NH4[+]-N and 99.2 % of PO4[3-]-P, more efficient than that with other types of biofilms and suspended microalgae. In an open-ended air-lift photobioreactor, the mixotrophic microalgal biofilm produced biomass at 0.12 g/(L·d) and removed 90.0 % of NH4[+]-N and 97.6 % of PO4[3-]-P. This study suggests that the mixotrophic microalgal biofilm shows promise in treating nutrient-rich wastewater and producing microalgal biomass for value-added products.

RevDate: 2025-07-04

Xue Y, A Yan (2025)

Capsaicin inhibits the biofilm of Klebsiella pneumoniae by targeting the transcriptional regulator SdiA.

Microbial pathogenesis, 207:107860 pii:S0882-4010(25)00585-6 [Epub ahead of print].

Pneumonia, particularly when caused by the bacterium Klebsiella pneumoniae, presents a major global health challenge. This gram-negative bacterium is a notable pathogen in healthcare-associated infections, leading to severe conditions such as urinary tract infections, pneumonia, and the bloodstream infections, mainly in immunocompromised subjects. The bacterium's ability to resist multiple antibiotics complicates the treatment, posing a major concern in hospital settings. Capsaicin, one the major capsaiciniods present in Capsicum plants, is known for the bacteriostatic and bactericidal properties, though detailed studies on effects of capsaicin on biofilm in K. pneumoniae is not thoroughly investigated. Preliminary analyses indicate that capsaicin can inhibit the growth of K. pneumoniae at MIC (256 μg/ml). Capsaicin effectively inhibits biofilm development (72.65 ± 3.23 %) and reduces the metabolic activity (46.64 ± 4.31 %) of biofilms. Furthermore, exopolysaccharide production was diminished along with the eradication of established biofilm by capsaicin. Treatment of capsaicin decreased the cell surface hydrophobicity and induced the intracellular ROS production. The transcription level of biofilm and QS-related genes were also downregulated in presence of capsaicin. Computational analysis revealed that capsaicin interacts with transcriptional regulator SdiA with binding energy -5.6 kcal/mol. Molecular simulations validated the stability of SdiA-capsaicin complex under physiological conditions. The complex was mainly stabilized by the van der Waals forces. This study shows the potential of capsaicin in managing pneumonia complications, particularly those caused by K. pneumoniae. The findings suggest that capsaicin may serve as a promising agent in development of new therapeutic drug to combat bacterial infections associated with biofilm and antibiotic resistance.

RevDate: 2025-07-02

Kumar V, Nayakvadi S, Prakash K, et al (2025)

Isolation, antimicrobial resistance and biofilm gene analysis of MRSA in clinical and sub-clinical bovine mastitis.

Microbial pathogenesis pii:S0882-4010(25)00576-5 [Epub ahead of print].

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant public health concern due to its zoonotic potential, multidrug resistance, and persistence in livestock environments. This study aimed to isolate and characterize MRSA from clinical and subclinical mastitis cases in dairy cows in the rural regions of North Bengaluru, India. A total of 133 milk samples from mastitis-affected cows were analysed, revealing that 48.8% (65/133) exhibited coagulase-positive colonies on Mannitol Salt Agar. Of these, 28 isolates were confirmed as S. aureus via detection of the nuc gene and among them, 16 isolates (12%) were positive for the mecA gene, confirming MRSA. Subclinical mastitis accounted for the majority of MRSA isolates (87.5%) suggesting that asymptomatic carrier of the pathogens. Antimicrobial susceptibility testing of isolates showed high resistance to cefoxitin (75%) and penicillin (68.75%), with highest sensitivity observed against chloramphenicol (93.75%), trimethoprim-sulfamethoxazole (87.5%), and linezolid (87.5%). Among MRSA isolates, 62.5% exhibited multidrug resistance. Molecular screening for biofilm and adhesion-associated virulence genes revealed that all MRSA isolates harboured cna and clfA, while 93.75% were positive for fnbpA and eno, and 81.25% for icaA and ebps. The agrI gene was present in 56.25% of isolates, indicating regulatory variability in biofilm-associated gene expression. These findings highlight the emerging role of MRSA in bovine mastitis, especially in subclinical infections, and emphasize the need for enhanced surveillance, responsible antimicrobial usage, and biosecurity interventions in dairy farming to mitigate the spread of drug-resistant pathogens.

RevDate: 2025-07-02

Hansen S, Thomsen K, Mattsson AH, et al (2025)

Pseudomonas aeruginosa vaccine identified by the AI-immunology™ platform improves outcomes in a murine biofilm lung infection model.

Vaccine, 61:127416 pii:S0264-410X(25)00713-3 [Epub ahead of print].

The Gram-negative opportunistic bacterial pathogen, Pseudomonas aeruginosa is considered by WHO as a "priority pathogen" for which new antibacterial strategies are urgently needed due to antimicrobial resistance development. In addition, P. aeruginosa is a cause of difficult to treat chronic infections due to its ability to form biofilms. Therefore, pseudomonal vaccines have been proposed as alternative strategies to combat these infections for the last 50 years, however, no vaccines are available on the market for human use. The aim of this study was to investigate the capacity of a vaccine composed of seven antigens, identified using EDEN™ (Efficacy Discriminative Educated Network) - a proteome-wide in silico antigen prediction model within AI-Immunology™ platform - in improving outcomes in a murine model of chronic P. aeruginosa lung infection. The primary endpoint was quantitative bacteriology (Colony forming units - CFU) in the lungs of immunized animals compared to control animals. The secondary endpoints were clinical signs (a clinical score), body temperature and weight loss. Mice immunized with the heptavalent combination vaccine had a significantly 1.2 log10 lower lung CFU compared to the control group. Furthermore, the vaccinated mice presented significantly fewer clinical signs of infection, had less reduction in body temperature and weight loss as, compared to control mice. There was a statistically significant correlation between the lung bacteriology and secondary endpoints. Antibodies against all seven antigens were measured by ELISA confirming their immunogenicity. The encouraging results obtained in this, and previous studies provide a proof-of-concept that EDEN™ is a useful tool in identifying vaccine antigens against P. aeruginosa and possibly other problematic pathogens.

RevDate: 2025-07-02

Jin Y, Zhou W, Chen W, et al (2025)

Penicillin-susceptible ST398 with strong biofilm-forming ability poses a significant threat to osteoarticular infections.

The Journal of antimicrobial chemotherapy pii:8182507 [Epub ahead of print].

BACKGROUND: Osteoarticular infections (OAIs), primarily caused by Staphylococcus aureus (both MSSA and MRSA), pose significant clinical challenges due to their heterogeneity and complexity.

OBJECTIVE: To investigate the epidemiology, clinical characteristics and bacterial features of S. aureus strains isolated from OAI patients treated at a major tertiary hospital in China over a 9-year period, with a focus on biofilm formation and colonization potential.

METHODS: A total of 178 S. aureus isolates (56.8% MSSA and 43.2% MRSA) were analyzed using whole-genome sequencing, antibiotic susceptibility testing, biofilm formation assays and phylogenetic analysis. A murine nasal colonization model and in vitro adhesion assays using A549 human epithelial cells were employed to evaluate colonization and adherence capabilities.

RESULTS: Penicillin-susceptible Staphylococcus aureus (PSSA) showed a significant rise during the study period, particularly within clonal complex ST398, which exhibited enhanced biofilm-forming capabilities. Phylogenetic analysis revealed minimal transmission events, suggesting independent cases. Comparative genetic analysis demonstrated distinct human-adaptive features in MRSA and MSSA-ST398 strains. PSSA-ST398 strains exhibited superior biofilm formation and increased adherence to human epithelial cells and murine nasal cavities compared with penicillin-resistant counterparts, indicating a potential advantage in colonization and persistence.

CONCLUSIONS: Penicillin-susceptible ST398 strains, particularly those with strong biofilm-forming capabilities, which increase their persistence in clinical settings, complicating treatment and eradication efforts, represent a significant threat to OAIs. Despite being penicillin-susceptible, these strains may still pose challenges due to their biofilm-mediated resistance and potential for chronic infection.

RevDate: 2025-07-02

Şensoy Gün B, Gurbanov R, B Tunalı (2025)

Biofilm-inhibiting ZnO@Eggshell nanocomposites: green synthesis, characterization, and biomedical potential.

Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine [Epub ahead of print].

This study explored the eco-friendly synthesis, characterization, optimization, and biomedical potential of zinc oxide-eggshell (ZnO@ES) nanocomposites using Althaea officinalis flower extract. HPLC analysis identified pink flower extract as the highest in quercetin (88.452 ppm), making it the optimal choice for synthesis. UV-Vis spectroscopy confirmed ZnO nanostructures (384 nm peak), while characterization analyses using different spectroscopic and microscopic techniques validated their successful incorporation within the eggshell matrix. The hemocompatibility of ZnO@ES nanocomposites was assessed through hemolysis tests, which demonstrated low hemolytic activity (<5%), ensuring blood compatibility. Antimicrobial assays against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans revealed significant inhibitory effects, particularly with ZnO@ES4. Agar well diffusion tests showed that while eggshell alone lacked antimicrobial activity, ZnO@ES2 formed inhibition zones against P. aeruginosa and E. coli, whereas ZnO@ES4 was effective against P. aeruginosa, E. coli, and S. aureus. Biofilm inhibition tests further demonstrated that ZnO@ES2 and ZnO@ES4 significantly reduced E. coli and P. aeruginosa biofilms, with ZnO@ES4 being more effective. MTT cytotoxicity assays using L929 fibroblast cells confirmed biocompatibility, with ZnO@ES2 enhancing cell proliferation. By repurposing eggshell waste, this study promotes a circular economy approach, transforming an abundant biowaste into value-added biomaterials. The green synthesis method eliminates the need for toxic chemicals, ensuring an environmentally friendly and sustainable clean production process. These findings support the development of antimicrobial and biocompatible nanocomposites with biomedical applications.

RevDate: 2025-07-03

Fujii A, Akatsu T, Souno H, et al (2025)

Enhanced dominance of nitrate-reducing bacteria using a combination of nitrate and erythritol in in vitro cultured oral biofilm.

Journal of oral microbiology, 17(1):2526069.

BACKGROUND: Oral nitrate-reducing bacteria are associated with good oral health, with inorganic nitrate specifically promoting the growth of these beneficial bacteria. Sugar alcohols affect the composition of oral microbiota, potentially impacting oral health. The present study aimed to investigate the combined effects of nitrate and sugar alcohols on nitrate-reducing bacteria and nitrate metabolism in oral microbiota cultured in vitro.

METHODS: Species-level microbial analysis using 16S rRNA gene sequencing of DNA extracted from the supragingival plaque-derived biofilm cultured under micro-aerobic conditions for 48 h with nitrate and/or sugar alcohols was conducted. Nitrate metabolites, lactate, and pH in culture supernatants were also measured.

RESULTS: The combined addition of nitrate and erythritol, but not xylitol or sorbitol, significantly increased the relative abundance of Haemophilus parainfluenzae and Neisseria subflava, which are nitrate-reducing bacteria. This shift was accompanied by a corresponding decrease in Streptococcus oralis, which simultaneously induced an increase in the nitrate-reducing capacity and a decrease in lactate production and acidification from sugar metabolism.

CONCLUSIONS: The combination of nitrate and erythritol serve as a preventive and therapeutic approach for periodontitis or dental caries by promoting the growth of oral commensal nitrate-reducing bacteria. However, human clinical studies are required to clarify these beneficial effects.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Xander C, Martinez EE, Toothman RG, et al (2025)

Treatment of bacterial biothreat agents with a novel purified bioactive lactoferrin affects both growth and biofilm formation.

Frontiers in cellular and infection microbiology, 15:1603689.

Lactoferrin is known to exhibit broad spectrum activity against a multitude of bacteria, fungi, and viruses due to its multi-functional mode of action. Recently, Lactea Therapeutics and its affiliates have developed a novel, patent-pending technology to purify naturally derived bovine lactoferrin (Lactea Lf) for use as a medical countermeasure that was not previously available. To assess the efficacy of Lactea Lf against biothreat pathogens, we performed biofilm inhibition assays and generated dose-response curves against Burkholderia pseudomallei, Burkholderia mallei, and Francisella tularensis for proof-of-principle studies. Here, we show that Lactea Lf can significantly inhibit biofilm and decrease the overall growth in a dose dependent manner for all Burkholderia species tested. Of note, Lactea Lf was found to completely inhibit biofilm formation by virulent B. pseudomallei without observing complete growth inhibition. The growth of F. tularensis was also significantly inhibited when cultured in the presence of Lactea Lf and appeared more sensitive to treatment when compared to B. pseudomallei. Based on these results, a pneumonic infection model using the F. tularensis LVS strain was performed prophylactically administering Lactea Lf and continuing treatment post challenge. No protection was observed in this model which prompted biodistribution studies using fluorescent tagged Lactea Lf. These experiments revealed that therapeutic material was mainly confined to the NALT region following intranasal delivery and then quickly dispersed or inactivated suggesting that future formulation and delivery method could be addressed to increase in vivo treatment efficacy. Taken together, these data support that Lactea Lf is a potentially new candidate for further studies as a broad-spectrum antimicrobial medical countermeasure with efficacy against several high priority biodefense-related bacterial pathogens.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Armoon M, Babapour E, Mirnejad R, et al (2024)

Evaluation of icaA and icaD Genes Involved in Biofilm Formation in Staphylococcus aureus Isolates from Clinical Sources Using Reverse Transcriptase PCR.

Archives of Razi Institute, 79(6):1329-1335.

Staphylococcus aureus is recognized for its capacity to generate biofilms, which facilitate bacterial adhesion to diverse substrates and present a significant challenge to therapeutic intervention. The process of biofilm formation is dependent on the icaABCD operon, with the icaA and icaD genes playing a pivotal role in this intricate process. The objective of this study is to investigate the role of these genes in the biofilm formation of S. aureus isolates sourced from clinical settings. A total of 100 S. aureus isolates were collected from clinical sources and subsequently subjected to DNA and RNA extraction using a commercial kit from Kiagen Co. To transcribe the RNA samples into cDNA, a commercial kit from Kiagen Co. was employed. The capacity to produce phenotypic and molecular biofilm formation was then measured using the microtiter plate method and PCR, respectively. The expression levels of the icaA and icaD genes were determined via RT-PCR (Reverse transcription polymerase chain reaction). The results indicated that 95% (95%) of the isolates were capable of producing biofilm, with 16 (16%) producing weak, 64 (64%) producing medium, and 15 (15%) producing strong biofilms. Furthermore, the icaA gene was detected in 72% of the isolates, while the icaD gene was detected in 58%. Of these isolates, 70 (97.2%) expressed the icaA gene, and 53 (73.6%) expressed the icaD gene. Conversely, four isolates (5.5%) that possessed the icaA gene but lacked the icaD gene did not form biofilm. One strain did not express either of the genes. The presence of either the icaA or icaD gene is crucial for the development of biofilm. However, further investigation is necessary to fully comprehend the intricacies of biofilm formation.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Soltani Borchaloee A, Moosakazemi Mohammadi LS, Khosh Ravesh R, et al (2024)

Prevalence of Biofilm and Efflux Pump Genes Expression by PCR and Antibiotic Resistance Pattern in Pseudomonas Aeruginosa.

Archives of Razi Institute, 79(6):1281-1286.

Pseudomonas aeruginosa is a significant pathogen responsible for nosocomial infections. P. aeruginosa is a multidrug-resistant (MDR) bacterium that is postulated to be the result of its plasmid-borne and intrinsic resistance to a number of pharmaceutical agents. This study examined the potential for biofilm formation, the distribution of the pslD, pelF, and algD genes, and the expression of the MexAB-OprM efflux pump genes. Furthermore, the study examined the pattern of antibiotic resistance in multi-drug resistant P. aeruginosa isolates obtained from a range of clinical samples. A total of 76 strains of P. aeruginosa were obtained for this investigation from a range of clinical specimens. The susceptibility of the isolates to antibiotics was evaluated using the disk agar diffusion method. In conclusion, the term "multi-drug resistance" (MDR) is used to describe a specific pattern of resistance. The isolates were evaluated for the presence of three pivotal biofilm genes and their antimicrobial resistance patterns against ten standard antibiotic disks. The data were analyzed using version 25 of the SPSS statistical software. The examination of the isolates revealed that the most antibiotic sensitivity was associated with polymyxin, piperacillin, and ciprofloxacin. Additionally, the prevalence of biofilm-producing genes, specifically pslD, pelF, and algD, was determined to be 68.4%, 80.3%, and 69.7%, respectively. The prevalence of MexAB-OprM efflux genes in the examined isolates was 89.5% for the mexA gene, 90.8% for the mexB gene, and 90.8% for the oprM gene. The majority of the isolates in this investigation exhibited the presence of efflux pump genes, as evidenced by the findings. Furthermore, a robust correlation was identified between a select number of efflux genes and biofilm formation or the antibiotics tetracycline, meropenem, amikacin, and polymyxin B.

RevDate: 2025-07-02

Vijay D, Bedi JS, Dhaka P, et al (2025)

Prevalence, antimicrobial resistance and biofilm forming ability of Escherichia coli in milk, animal handlers and slurry samples from dairy herds of Punjab, India.

Frontiers in veterinary science, 12:1553468.

Antimicrobial-resistant Escherichia coli serves as an indicator for monitoring the occurrence of antimicrobial resistance (AMR) at the human, animal, and environmental interface. The present study employs a 'One Health' framework to determine the prevalence, phenotypic and genotypic characterisation of the AMR profile and biofilm forming ability of E. coli isolates from milk, hand swabs and slurry samples of 405 dairy herds in Punjab, India. An overall prevalence of E. coli was 34.3% (139/405) (95% CI: 0.30 to 0.39) from pooled milk samples, 9.1% (37/405) (95% CI: 0.06 to 0.12) from the hand swabs of animal handlers and 64.4% (261/405) (95% CI: 0.60 to 0.69) in the slurry samples. Multidrug resistance (resistance to 3 or more classes of antimicrobials) was exhibited by 24.4% (34/139) of E. coli isolates from milk, 40.5% (15/37) from hand swabs, 60.5% (158/261) from slurry samples. Moreover, of the E. coli isolates, 11.51% (16/139) from milk, 24.32% (09/37) from hand swabs and 31.42% (82/261) from slurry samples were resistant to 5 or more antimicrobial classes. On molecular characterisation, 19.4% (27/139) of E. coli isolates from milk, 37.8% (14/37) from hand swabs, and 33.3% (87/261) from slurry samples harboured various genes. Principal component analysis and Shannon-Wiener diversity indices highlighted varying β-lactamase (ESBL/AmpC β-lactamase) gene distributions across samples, with milk exhibiting the highest diversity. Logistic regression analysis revealed a significant protective effect of milk hygiene scores against E. coli occurrence (OR = 0.18; 95% CI: 0.13-0.26, p < 0.001), while linear regression demonstrated a significant negative association between milk hygiene scores and the Multiple Antibiotic Resistance (MAR) index (p = 0.02). Biofilm assays revealed that 19.2% of isolates were strong biofilm formers, with a strong association (p < 0.01) between biofilm formation potential and MAR index. The multidrug-resistant (MDR) isolates were predominantly moderate biofilm producers, with 23.5% (milk), 20% (hand swabs), and 24.1% (slurry) classified as strong biofilm formers. The study findings underscore the need for One Health-integrated strategies to holistically address AMR challenges at the dairy-environment interface.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Sadiq SI, JA Ghafil (2025)

Polyhydroxybutyrate nanoparticle improving the sensitivity of Pseudomonas aeruginosa to ceftriaxone and reducing the biofilm formation in vitro.

Polimery w medycynie, 55(1):31-37.

BACKGROUND: Polyhydroxybutyrate nanoparticles (PHB-NPs) represent a promising strategy for addressing the growing threat of bacterial resistance to antibiotics - a major concern in global public health. Despite their potential, there is a noticeable gap in the current literature regarding their ability to enhance the efficacy of existing antibiotic therapies.

OBJECTIVES: This study investigates the synergistic effect of PHB-NPs in enhancing the antibacterial activity of ceftriaxone (CRO) against Pseudomonas aeruginosa, with a particular focus on mitigating key virulence factors such as biofilm formation and adhesion.

MATERIAL AND METHODS: Polyhydroxybutyrate nanoparticles were synthesized using the pH gradient and sonication method. The antibacterial activity of PHB-NPs, CRO and the combined formulation (PHB-NP-CRO) was assessed using minimum inhibitory concentration (MIC) testing and the well diffusion method. Additionally, the effects of these formulations on P. aeruginosa biofilm formation on an abiotic surface (polystyrene) and bacterial adhesion to human oral mucosal epithelial cells (OMECs) were evaluated.

RESULTS: The diameters of the prepared PHB-NPs ranged from 15 nm to 34 nm, with an average size of 28.2 ±6.3 nm. All P. aeruginosa isolates were capable of biofilm production. A negative correlation was observed between the diameter of the CRO inhibition zones and the extent of biofilm formation among the 20 isolates. The MICs for PHB, PHB-NPs, CRO, and the combined formulation (PHB-NP-CRO) were 2,000, 1,000, 250, and 62.5 μg/mL, respectively. Sub-MIC concentrations (as low as 1/32 MIC) of both CRO and PHB-NP-CRO exhibited significant inhibitory effects on biofilm formation and bacterial adhesion to human OMECs (p < 0.050).

CONCLUSIONS: The combination of PHB-NPs with CRO significantly enhances the antibacterial activity of CRO against P. aeruginosa. Moreover, sub-inhibitory concentrations (sub-MICs) of both PHB-NP-CRO and CRO alone effectively reduce the bacterium's ability to form biofilms and adhere to biotic surfaces.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Vodianyk A, Poniatovskyi V, V Shyrobokov (2025)

Biofilm formation on different types of central venous catheters in vitro.

BMC research notes, 18(1):267.

OBJECTIVE: To determine the intensity of biofilm formation on different types of central venous catheters in vitro by clinical isolates of bloodstream infection pathogens in Ukraine.

METHODS: Four clinical strains of Klebsiella pneumonia, four clinical strains of Staphylococcus aureus and four clinical strains of Pseudomonas aeruginosa were isolated from patients from Ukrainian tertial level children`s hospitals during 2023 with bloodstream infections including central line associated blood stream infections. Capacity to form biofilms was assessed using microtiter plate assay and ability to form biofilms in vitro was evaluated on three types of catheters: 1st catheter- surface from medical polyvinyl chloride; 2nd- surface from long-chain polymer based on methacrylate, polyethylene glycol and antiseptic polymeric biguanide; 3rd- silicon surface impregnated with an antimicrobial combination of chlorhexidine acetate and chlorhexidine. Scanning electron microscopy was conducted to assess biofilm formation on the surface of catheters.

RESULTS: Clinical isolates of K pneumonia had similar intensity of biofilm formation on different types of catheters: 1st catheter type- intensity of biofilm formation 0.30-0.34 OD; 2nd catheter type- 0.28-0.37 OD; 3rd catheter type- 0.32-0.37. Clinical isolates of S. aureus form biofilms on all types of catheters by biofilm formation on first type of catheter was lower compared to third type: 1st catheter type- 0.26-0.38 OD; 2nd catheter type- 0.3-0.4 OD; 3rd catheter type- 0.31-0.4 OD (p < 0.05 comparing with 1st catheter). Clinical isolates of P. aeruginosa had the highest ability to form biofilms on catheters. The ability to form biofilms was the most prominent of 3rd types of catheters: 1st catheter type- intensity of biofilm formation 0.38-0.66 OD; 2nd catheter type- 0.44-0.6 OD; 3rd catheter type- 0.54-0.91 OD (p < 0.05 comparing with 1st and 2nd catheter).

CONCLUSIONS: P.aeruginosa clinical strains form stronger biofilms compared to other bacteria on all types of catheters. All clinical isolates were able to form biofilm on catheter after 24 h incubation however intensity of biofilm formation by S.aureus and P.aeruginosa on catheters from medical polyvinyl chloride was lower than on other types. There was no difference in biofilm formation on different types of catheters by K.pneumonia strains in vitro.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Hu Y, Chen Z, Mao X, et al (2025)

A novel tetrahedral framework nucleic acid-based antibiotic delivery system: overcoming biofilm barriers to combat chronic infections.

Journal of nanobiotechnology, 23(1):465.

BACKGROUND: Overcoming bacterial biofilm barriers to enhance the efficacy of antibiotics remains a major therapeutic challenge, necessitating the development of efficient and biocompatible drug delivery systems. While framework nucleic acids (FNAs) have emerged as promising candidates for overcoming biological barriers, their biofilm penetration efficiency and mechanistic interactions require systematic exploration. This study evaluates the biofilm-penetrating capacity of FNAs with distinct topological configurations (linear, triangular, and tetrahedral), investigates their antibiotic delivery performance in biofilm-infected models, and elucidates the structure-dependent interactions between FNAs and bacteria.

RESULTS: DNA tetrahedron (Td) demonstrated superior biofilm penetration, exhibiting 44-fold and 11-fold stronger fluorescence intensity at a biofilm depth of 20 μm compared to linear and triangular counterparts, respectively, while maintaining structural stability. The optimized polymyxin B-loaded Td (PMB@Td, with a PMB: Td ratio of 10:1) enhanced biofilm permeability by 6-fold relative to free PMB. PMB@Td outperformed conventional liposome-encapsulated PMB (PMB@Lipo), achieving half-maximal biofilm eradication concentrations (MBEC50) of 12.8 µM versus 16.3 µM for PMB@Lipo. In murine models of biofilm- associated skin and pulmonary infections, PMB@Td effectively controlled bacterial burden and mitigated inflammatory responses without observable toxicity. Mechanistic studies revealed that the tetrahedral topology facilitated efficient diffusion within the biofilm matrix and enhanced Td adhesion to bacterial membranes.

CONCLUSIONS: This work establishes Td as a robust nanoplatform for overcoming biofilm-mediated antibiotic resistance. The topology-dependent interactions provide critical design principles for engineering next-generation nanocarriers against biofilm-associated chronic infections, with significant translational potential in antibiofilm therapy.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Marra D, Rizzo M, S Caserta (2025)

Microfluidics unveils role of gravity and shear stress on Pseudomonas fluorescens motility and biofilm growth.

NPJ biofilms and microbiomes, 11(1):122.

Biofilm proliferation in confined environments is a challenge in biomedical, industrial, and space applications. Surfaces in contact with fluids experience varying bulk stresses due to flow and gravity, factors often overlooked in biofilm studies. This research quantifies the combined effect of gravity and shear stress on Pseudomonas fluorescens SBW25 motility and biofilm growth. Using a rectangular-section microfluidic channel under laminar flow, we compared top and bottom surfaces, where gravity either pulls bacteria away or pushes them toward the surface. Results revealed an asymmetric bacterial distribution, leading to varying surface cell densities and contamination levels. We also analyzed spatial reorganization over time and classified bacterial motility under flow. Findings show that external mechanical stresses influence both motility and biofilm morphology, impacting biocontamination patterns based on shear stress and gravity direction. This study provides insights into biofilm control strategies in diverse environments.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Zhou Y, Huang F, H Lin (2025)

Berberine chloride hydrate impairs Streptococcus mutans biofilm formation via inhibiting sortase A activity.

NPJ biofilms and microbiomes, 11(1):120.

Dental caries is a biofilm-associated chronic progressive disease, results from the dissolution of mineralized tooth tissue by acidic generated from bacterial sugar fermentation. S. mutans, a prominent pathogen of dental caries, is acknowledged for its role in cariogenic biofilm formation, utilizing Sortase A (SrtA) to catalyse surface proteins, thus promoting biofilm formation. In our previous studies, the inhibitory effect of the berberine chloride hydrate (BH) on S. mutans biofilms was confirmed. Here, we further investigate the influence of BH on S. mutans biofilm-induced bovine enamel caries model and explore the effect of BH on S. mutans SrtA activity. We found that BH inhibited S. mutans biofilm formation in bovine enamel model, leading to a reduction in demineralization. Furthermore, we identified and characterized SrtA, which might catalyze SpaP of S. mutans to form fibrillar amyloid aggregates. Our findings showed that BH inhibited SrtA activity by binding to essential amino acid residues LEU-111, MET-123, and ARG-213. BH inhibited amyloid fibers formation by downregulating the expression of srtA gene, thus disrupting S. mutans biofilm formation. Taken together, our study provides new insight into the mechanism of antibiofilm activity of BH and reveals great potential for anticaries clinical applications.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Liao C, Liu Q, Luo G, et al (2025)

Human neutrophil α-defensin HNP1 interacts with bacterial OmpA to promote Acinetobacter baumannii biofilm formation.

Nature communications, 16(1):5629.

Acinetobacter baumannii is the causative agent of a wide range of nosocomial and community-acquired infections that remain extremely difficult to treat due largely to its antibiotic resistance contributed, in part, by biofilm formation. We find that the prototypic human neutrophil α-defensin HNP1, present in the bronchoalveolar lavage fluids from Acinetobacter baumannii-infected patients, promotes Acinetobacter baumannii biofilm formation through interactions with the bacterial outer membrane protein OmpA. As a result of HNP1-enhanced biofilm formation, Acinetobacter baumannii becomes more tolerant to antibiotics and more readily colonizes host cells and tissues. These unexpected findings contrast the protective roles HNP1 plays in innate immunity against microbial infection, showcasing an example of the host-pathogen arms race where a host defense peptide is exploited by a microbe for pathogenicity.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Watchaputi K, Songdech P, Jayasekara C, et al (2025)

Yeast-derived glycolipids disrupt Candida biofilm and inhibit expression of genes in cell adhesion.

Scientific reports, 15(1):20405.

Candida albicans is a leading fungal pathogen in humans, responsible for infections that span from mucosal surfaces to severe systemic diseases. This study aimed to investigate potential ability of yeast-derived glycolipids from Meyerozyma guilliermondii as an antifungal against Candida albicans biofilms. Glycolipid extract (64 µg/mL) reduced metabolic activity by 50% in both immature and mature biofilms, while biofilm mass was reduced at higher concentrations of 128 and 256 µg/mL, respectively. Adhesion, a key step in biofilm formation, decreased by over 50% when cells were treated with glycolipids (16 µg/mL). Gene expression analysis indicated that glycolipids downregulated key adhesion-related gene ACE2, confirming their role in disrupting C. albicans adhesion. Importantly, structural changes in C. albicans biofilms, including reduced hyphal production and wrinkled cell surfaces, were observed under SEM. Nocodazole, a cell cycle synchronizer, arrested cells in the G2/M phase, enhancing glycolipid's effects on lowing expression of biofilm-related genes. Lipidomics analysis also revealed a compound with same mass as sophorolipid. Furthermore, purification glycolipid fraction revealed two main forms: lactonic and acidic, compared to standards. Acidic fraction showed superior antibiofilm and anti-inflammatory activity with low toxicity. These findings highlight the potential of yeast-derived glycolipids for biopharmaceutical applications, particularly in treating Candida biofilms.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Baseri M, Naseri A, Radmand F, et al (2025)

Effect of nano liposomal herbal extracts against biofilm formation and adherence of streptococcus mutans.

Scientific reports, 15(1):21917.

Dental caries results from the colonization of oral microorganisms, such as Streptococcus mutans (S. mutans), and their adherence to teeth is the initial step in this process. Therefore, blocking the attachment to the enamel surface would lead to inhibition of biofilm formation. We investigated the antibacterial, antibiofilm, and anti-attachment effects of nano-liposomal herbal extracts, including Shirazi thyme (Zataria multiflora; Z. multiflora), Summer savory (Satureja hortensis; S. hortensis), and Red Cabbage (Brassica oleracea var. capitata f. rubra; BRSOR), against biofilm formation and adherence of S. mutans. S. mutans strain ATCC 35,668 was cultured, and aqueous extracts were prepared. An antibacterial assessment was conducted using the minimum inhibitory concentration (MIC) method by the broth microdilution method. Nanoliposomes of Z. multiflora (Z-NLP) and S. hortensis (S-NLP) were prepared and characterized. Anti-biofilm assay was performed using the minimum biofilm inhibitory concentration (MBIC) test. Finally, the effects of nanoliposomal herbal extracts were evaluated against S. mutans attachments to glass and enamel surfaces. The aqueous extract of BRSOR did not exhibit an antibacterial effect, and therefore, it was abandoned from further consideration in the work. No significant difference was observed between the herbal extracts and the control groups in MIC. Extract-loaded nanoliposomes demonstrated a significantly higher anti-biofilm effect compared to aqueous extracts. Among the study groups, only Z-NLP had a similar attachment level to enamel with Chlorhexidine 0.2%. According to the results, Z-NLP showed a significant effect on the attachment of S. mutans to enamel, thereby inhibiting biofilm formation.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Ibrahim SI, Parambil AM, Jha N, et al (2025)

Targeting ESKAPE pathogens with ZnS and Au@ZnS Core-Shell nanoconjugates for improved biofilm control.

Scientific reports, 15(1):21407.

The escalating prevalence of antibiotic-resistant infections and implant-related complications caused by biofilm-forming pathogens from the ESKAPE group, as identified by the World Health Organization (WHO), underscores the urgent need for innovative anti-biofilm strategies. Their occurrence on medical implants & prosthetic devices, as well as nosocomial infections in co-morbid patients, has become a global concern in the healthcare sector. In response, we investigated the efficacy of as-synthesized ZnS quantum dots (ZnS QD) and novel Au@ZnS nanoconjugates (Au@ZnS NC) against a spectrum of ESKAPE pathogens. The present study aimed to elucidate their antibacterial and anti-biofilm efficacy, focusing on Acinetobacter baumannii, Enterobacter cloacae, Staphylococcus epidermidis, Enterococcus faecium, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus and Enterobacter aerogenes pathogens. The novel synthesis and application of ZnS QD and Au@ZnS core-shell NC demonstrate exceptional anti-biofilm efficacy, stability, and solubility in aqueous environments. Utilizing minimum inhibitory concentration (MIC) assays, tube dilution, and biofilm formation assay, we noticed a significant reduction in biofilm formation and extracellular polymeric substances (EPS) production upon treatment with Au@ZnS NC, even at low concentrations. Further investigations, including cell permeability assay, reactive oxygen species analysis, and comet analysis, demonstrated that the Au@ZnS NC induced oxidative stress, destabilizing cell structure, macromolecule destruction, and DNA strand breakage. Notably, Au@ZnS nanoconjugates effectively inhibited biofilm formation within 24 h across all tested strains, outperforming ZnS quantum dots. This research highlights the potential of Au@ZnS nanoconjugates to revolutionize infection control on medical devices and implants, offering a promising solution to the global healthcare challenge posed by biofilm-forming pathogens as we also observed minimal bacterial colonization on Au@ZnS treated urinary catheters.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Peng L, Wen S, Yu L, et al (2025)

Characterizations of sulfate-reducing bacteria biofilm formed on N80 carbon steel in artificial shale gas field produced water.

Scientific reports, 15(1):22388.

The corrosion of steel caused by sulfate-reducing bacteria (SRB) has been a big trouble resulting in the service failure of engineering equipment, and SRB biofilm is the direct reason leading to the corrosion acceleration. In this work, SRB biofilms formed on N80 carbon steel in an artificial shale gas field produced water with different test conditions were characterized carefully by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), fluorescence microscope, and three-dimensional stereoscopic microscope. Results demonstrate that test time, temperature, and initial SRB cell concentration can influence the growth and surface morphology of biofilm, and test time and temperature are primary factors. There is a highest corrosion rate of 0.100 ± 0.005 mm/y on the seventh day due to the high biological activity, and then corrosion rates gradually decline with time. The formed biofilms at different time have a similar morphology and the contents of elemental S in biofilms are high also suggesting SRB corrosion. Temperature can influence the biological activity of SRB, and then affect the formation of SRB biofilms. SRB has a higher biological activity at 20 and 37 °C than that of at 60 and 80 °C. The influence of initial SRB cell count differences on biofilm is weak.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Leifels M, Cheng D, Cai J, et al (2025)

Biofilm detachment significantly affects biological stability of drinking water during intermittent water supply in a pilot scale water distribution system.

Scientific reports, 15(1):22408.

Intermittent service provision (IWS) in piped drinking water distribution systems is practiced in countries with limited water resources; it leads to stagnant periods during which water drains completely from de-pressurized pipes, increasing the likelihood of biofilm detachment upon reconnection when water is supplied to the consumer and thus affecting water quality. Our study examines the impact of uninterrupted or continuous water supply (CWS) and IWS on microbial communities and biofilm detachment, using data from three 30-day experiments conducted in an above-ground drinking water testbed with 90-m long PVC pipes containing residual monochloramine. Flow cytometry (FCM) revealed a significant increase in total and intact cell concentrations when water was supplied intermittently compared to CWS, and the microbial alpha-diversity was significantly higher in CWS sections by both 16S rRNA gene metabarcoding and phenotypic fingerprinting of flow cytometry data. Nitrate levels in the water were significantly higher during initial intermittent flow due to the activity of nitrifying bacteria in biofilms exposed to stagnant water in pipes. Overall, biofilm detachment significantly affects the biological stability of drinking water delivered through IWS compared to CWS. We developed a novel biofilm detachment potential index derived from FCM data to estimate the minimum amount of water needed to be discarded before microbial cell counts and community composition return to baseline levels.

RevDate: 2025-07-02
CmpDate: 2025-07-02

Abdelhakeem E, Attia H, Hashem MM, et al (2025)

Innovative Antimicrobial Nanofibers: Natural Integrations for Enhanced Wound Healing and Biofilm Disruption.

AAPS PharmSciTech, 26(6):181.

Wound infections caused by multidrug-resistant bacteria present a substantial challenge in healthcare. Nanofibers, particularly when infused with natural extracts, are emerging as promising platforms for antimicrobial applications. This study investigates the potential of Anastatica hierochuntica extract-loaded electrospun nanofibers prepared with thermoplastic polyurethane for combating infections and promoting wound healing. Electrospinning was utilized to prepare nanofibers infused with Anastatica hierochuntica extract, resulting in uniform rod-shaped structures confirmed by scanning electron microscopy. The hydrophilicity of the nanofibers was assessed through water contact angle (WCA) measurements and swelling tests. Mechanical properties, including strain and stress were evaluated to determine suitability for drug delivery. The formulation with optimal properties, designated as NF20, underwent further investigation. Drug release profiles were analyzed over 72 h, and antimicrobial efficacy was tested against various pathogens, with comparisons made to Silymarin as a standard. A biofilm study evaluated the anti-virulence activity, while wound healing assays assessed the optimized extract loaded nanofibers potential in fostering tissue repair. The extract-loaded nanofibers exhibited enhanced hydrophilicity, with a WCA of 43.1 ± 0.6° and swelling of 216.67 ± 2.36% after 1 h. NF20 demonstrated superior mechanical properties, with strain and stress values of 67.6% and 0.0486 N/mm[2], respectively. The sustained release profile indicated 73.40 ± 1.31% release after 72 h. Antimicrobial tests revealed significant reductions in minimum inhibitory concentration, minimum bactericidal concentration, and minimum fungicidal concentration against key pathogens. The biofilm study confirmed extract loaded nanofiber's efficacy in inhibiting biofilm formation and disrupting established biofilms. These findings underscore the potential of the extract-loaded nanofiber composed of thermoplastic polyurethane as innovative wound dressings that enhance antimicrobial properties, promote accelerated healing and support tissue regeneration.

RevDate: 2025-07-01
CmpDate: 2025-07-02

Johnson MP, Al Bataineh MT, Sreedharan SP, et al (2025)

Vm and ζ-potential of Candida albicans corelate with biofilm formation.

Scientific reports, 15(1):22475.

Microbial biofilms are known to defend against the host's immune system and provide resistant to antimicrobial medications. Biofilms can form on various human organ systems spanning the gastrointestinal, respiratory, cardiovascular, and urinary organ systems. Conditions caused by the yeast Candida albicans can range from irritating thrush, to systemic and life-threatening candidiasis. Initial contact between organism and surface is mediated electrically, with subsequent interactions developed biochemically. Since different cells have different electrical characteristics, we hypothesised that alteration in these properties may align with different strains' propensity for biofilm formation. We used three strains of C. albicans with different tendencies for biofilm formation and filament phenotype (the most filamentous strain nrg1 Δ/Δ, the least filamentous ume6 Δ/Δ, and wildtype DK318), we investigated the passive electrical properties, membrane potential Vm and ζ-potential at two conductivities. Results suggest Vm and ζ-potential correlate with a cell's ability to form biofilms, suggesting correlation between membrane potential, ζ-potential and biofilm formation. Understanding this relationship may suggest potential routes to future prevention of biofouling and biofilm-related illness.

RevDate: 2025-07-01

Hatamian G, Noghabi ZS, Shakeri A, et al (2025)

Chalcone derivatives against biofilm production of Streptococcus mutans by glucosyltransferase C inhibition.

Biochemical and biophysical research communications, 777:152273 pii:S0006-291X(25)00988-X [Epub ahead of print].

Dental caries remain an unresolved public health issue. Streptococcus mutans, a principal microorganism in the mouth, is closely associated with the onset and progression of dental caries. S. mutans adheres to tooth surfaces and synthesizes extracellular polysaccharides via the enzyme glucosyltransferase (Gtf), utilizing sucrose and forming biofilms. GtfC is linked to soluble and insoluble glucan synthesis, a significant factor in the adhesion of S. mutans to tooth surfaces and bacterial cell aggregation within biofilms. Chalcones, primary precursors for flavonoid and isoflavonoid biosynthesis, have demonstrated notable therapeutic efficacy in treating various diseases, including anti-inflammatory, antibacterial, and anticancer effects. This study aims to evaluate the inhibitory effects of six chalcone derivatives on GtfC, the prevention of biofilm formation by S. mutans, and the assessment of the cytotoxicity of these derivatives. To predict interactions between chalcone derivatives (5a, 5b, 5d, 5h, NME2, and BA) and GtfC, molecular docking was employed. The effectiveness of chalcone derivatives in inhibiting S. mutans biofilm formation and evaluating the potential of the compounds to destroy biofilms was assessed using a colorimetric method, with dye absorbance measured by an ELISA reader. The same method was applied for cytotoxicity assessment. All chalcone derivatives inhibited the growth of S. mutans, S. sanguinis, and S. salivarius, exhibiting antibiofilm properties against S. mutans. Compounds 5a, 5b, 5d, and NME2 successfully eradicated the S. mutans biofilm. All compounds demonstrated low cytotoxicity on HepG2 cells. The results indicate that compound 5a exhibited the strongest effect among the six chalcone derivatives, showing effectiveness at lower concentrations in all assays, including MBIC and MBEC tests.

RevDate: 2025-07-01
CmpDate: 2025-07-01

Chaudhary N, Ahmad I, Samreen , et al (2025)

Prevalence of Biofilm-Forming, ESβLs and Metallo-β-lactamase Producing Gram-Negative MDR Bacteria in the Domestic and Hospital Wastewater of Aligarh City.

Current microbiology, 82(8):354.

Gram-negative pathogenic bacteria are a major contributor to antibiotic-resistant infections in hospitals and communities. The emergence of multidrug resistance (MDR) and biofilm formation complicates chemotherapy. This study aimed to assess the prevalence of multidrug-resistant (MDR) biofilm-forming, extended-spectrum beta-lactamase (ESβL) and metallo-beta-lactamase (MβL) producers in wastewater, which pose a public health threat. During 2022-2023, 117 enteric/Gram-negative isolates were isolated using selective culture techniques. Antimicrobial resistance was assessed via disc diffusion assay. ESβL and MβL production was confirmed through phenotypic and PCR-based methods. Biofilm formation was determined using a microtiter plate assay. Biofilms developed on glass coverslips were visualized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Isolates with bla-CTX-M, bla-SHV, and bla-NDM-1 genes were identified by partial 16S rRNA gene sequencing. A total of 93.16% of isolates were resistant to multiple drug classes (≥ 4), with the increased resistance to ampicillin (100%) and the lowest to gentamicin (12.82%). Biofilm assays indicated that 32.48% of MDR strains formed strong biofilms, 31.62% moderate, and 35.90% weak. β-lactamase activity appeared in 58.97% of isolates, with 56.41% confirmed as ESβL producers. PCR detection in ESβL-positive strains showed 84.61% carried CTX-M, 46.15% SHV, and 53.84% NDM-1 genes. 16S rRNA gene sequencing identified selected MDR strains as Escherichia coli (5), Klebsiella pneumoniae (1), Pseudomonas aeruginosa (1), Salmonella sp. (1), Enterobacter sp. (1), Citrobacter sp. (1), and Proteus sp. (1). The findings reveal the prevalence of biofilm-forming, ESβL, and MβL-producing Gram-negative pathogens in Aligarh's wastewater, underscoring the need for effective treatment to reduce public health risks from MDR bacteria and AMR genes.

RevDate: 2025-07-02

Zareshahrabadi Z, Sahmeddini S, Meimandinezhad M, et al (2025)

Influence of Filler Content and Polishing on Candida and Streptococci Biofilm Formation in Resin-Based Composites: An In Vitro Evaluation.

The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale, 2025:5734405.

Aim: The purpose of this study was to investigate the impact of filler content and polishing of resin-based composites on in vitro biofilm formation of Candida and Streptococci species. Materials and Methods: Specimens of four commercially available resin-based composites including Z100, P60, Z250, and Z350, with different filler amounts and volumes, were prepared according to the manufacturer's instructions. Each group was divided into polished and unpolished specimens, which were then placed in a 24-well tissue culture plate with microbial suspension and incubated. The XTT technique was used to evaluate biofilm formation. Results: Z250 resin-based composites, which had the highest percentage of filler (68%), had the highest biofilm metabolic activity. A significantly less microbial biofilm metabolic activity was noted on P60 polished resin-based composites than on unpolished groups (p < 0.001). Polishing procedures reduce biofilm metabolic activity. Streptococcus salivarius produced the least biofilm metabolic activity among the Streptococcal species (p < 0.001). However, there were no statistically significant differences between Candida species in the biofilm metabolic activity. Conclusion: The results revealed that the amount of filler in resin-based composites had a major impact on the biofilm metabolic activity. Therefore, resin-based composites with a minimized excess resin matrix, minimized filler amount, and smoother surfaces might be more useful in reducing biofilm metabolic activity and secondary caries. These findings may be useful for modifying novel resin-based composite formulations to improve oral health and patient wellbeing.

RevDate: 2025-06-30

Bruno JS, Heidrich V, Restini FCF, et al (2025)

Dental biofilm serves as an ecological reservoir of acidogenic pathobionts in head and neck cancer patients with radiotherapy-related caries.

mSphere [Epub ahead of print].

UNLABELLED: Radiotherapy-related caries (RRC) is an aggressive and debilitating oral toxicity that affects half of the patients who undergo radiotherapy for head and neck cancer. However, the etiology of RRC is not fully established, and there are no clinically validated methods for preventing it. To gain a better understanding of the risk factors and the microbiome's role in causing RRC, we compared clinicopathological characteristics, oncological treatment regimens, oral health condition, and the oral microbiota at three different oral sites of radiotherapy-treated patients with (RRC+) and without radiotherapy-related caries (RRC-). We observed no significant differences between these groups in the clinicopathological characteristics and treatment regimens. However, RRC+ patients were older and had poorer oral health conditions at the start of the radiotherapy treatment, with a lower number of teeth and a higher proportion of rehabilitated teeth. RRC+ patients had lower microbiota diversity and the dental biofilm of RRC+ patients displayed striking alterations in microbiome composition compared to RRC- patients, including enrichment of acidogenic species and altered metabolic potential, with a higher abundance of genes linked to energy-related pathways associated with the synthesis of amino acids and sugars. We also compared the microbiota of RRC+ tissue with conventional caries tissue, revealing lower bacterial diversity and enrichment of Lactobacillaceae members in RRC+. The insights into the irradiated oral microbiota enhance the understanding of RRC etiology and highlight the potential for microbial-targeted therapies in its prevention and treatment.

IMPORTANCE: This study focuses on a dedicated collection of diverse oral sites to comprehensively investigate microbial differences between patients who develop RRC and those who do not. RRC is a severe oral disease that profoundly impacts on the oral health and overall quality of life of cancer survivors. Leveraging shotgun metagenomics, we characterize the unique microbial variations in in vivo irradiated dental biofilms, unveiling novel insights into the microbial ecology of radiotherapy-treated patients. Furthermore, this research integrates extensive data on oral health and oncological profiles, providing a comprehensive understanding of the intricate relationship between oral microbial communities and the outcomes of radiotherapy-induced toxicity.

RevDate: 2025-07-02

Bhaumik R, Beard A, Harrigan O, et al (2025)

Role of SMF-1 and cbl pili in Stenotrophomonas maltophilia biofilm formation.

Biofilm, 9:100253.

Stenotrophomonas maltophilia is an emerging multidrug-resistant, Gram-negative opportunistic pathogen. It causes many healthcare-associated infections such as sepsis, endocarditis, meningitis, and catheter-related urinary tract infections. It also affects individuals with cystic fibrosis, exacerbating their lung condition. S. maltophilia often causes pathogenesis through the formation of biofilms. However, the molecular mechanisms S. maltophilia uses to carry out these pathogenic steps are unclear. The SMF-1 chaperone/usher pilus has been thought to mediate S. maltophilia attachment. To confirm this role, we created an isogenic deletion of the smf-1 pilin gene and observed a defect in biofilm compared to wild type. We also discovered an additional chaperone/usher pilus gene cluster: cbl. Mutation of cbl also affects biofilm levels. Intriguingly, through transmission electron microscopy studies, we found suggestive evidence that the mutation of one pilus (e.g. smf) is not phenotypically compensated by another (e.g. cbl). Additionally, infection of Galleria mellonella larvae revealed increased virulence of an smf-1 deletion mutant and an smf-1 cbl double deletion mutant. Together, these studies show that pili have an important role in switching between acute and chronic infections in conducting S. maltophilia virulence. Understanding their activity may help identify therapeutic targets for this pathogen.

RevDate: 2025-07-02

Coenye T, Goeres DM, Kjellerup BV, et al (2025)

A guide to publishing in Biofilm: how to avoid a desk rejection.

Biofilm, 9:100282.

RevDate: 2025-07-02

Rajasekharan SK, Angelini LL, Kroupitski Y, et al (2025)

Mitigating Candida albicans virulence by targeted relay of pulcherriminic acid during antagonistic biofilm formation by Bacillus subtilis.

Biofilm, 9:100244.

The antagonistic biofilms formed by probiotic Bacilli may significantly mitigate persistent strains of Candida albicans, which are often involved in severe oral, vulvovaginal or systemic infections in humans. Here, we report on a spatiotemporal antagonistic activity mediated through pulcherriminic acid (PA) production by biofilm-forming B. subtilis, which is subsequently transported to the extracellular environment and binds ferric iron to form red-coloured pigment pulcherrimin. We show that the pulcherrimin building-up is targeted towards the C. albicans macrocolony via B. subtilis biofilm branching and successive PA relay. Furthermore, biofilm-forming B. subtilis cells demonstrate robust hyphal colonization that results subsequent eradication of C. albicans. Besides, extracted pulcherrimin mitigates C. albicans biofilm formation and yeast-to-hyphae (Y-H) transition. We further find that the mode of hyphal colonization could be regulated via SpoA-SinI pathway, while pulcherrimin relay is connected to surfactin production machinery. We assume therefore that the pulcherrimin relay for iron hijacking, in parallel to the direct hyphal colonization by biofilm-forming Bacilli, may provide a promising platform for developing therapeutic concepts to overcome antibiotic persistence in pathogenic yeasts.

RevDate: 2025-07-02

Abrantes PMDS, Chesnay Stuurman K, Arthur Klaasen J, et al (2024)

Monitoring of Candida biofilm inhibition by Galenia africana using real-time impedance-based technology.

Current medical mycology, 10:.

BACKGROUND AND PURPOSE: Yeasts of the Candida genus are responsible for localized and disseminated infections, especially in immunocompromised populations. These infections are exacerbated by the rapid increase in drug-resistant strains, which limits treatment options and increases patient morbidity and mortality. Therefore, the utilization of easily accessible natural products as alternatives to conventional medicines has gained interest. South Africa is home to a rich biodiverse natural flora of which many are known for their antimicrobial activity, including the antifungal effects of their plant extracts. Galenia africana (kraalbos) is a local indigenous plant found to have various traditional uses, including the treatment and prevention of various human infections.

MATERIALS AND METHODS: In this study, the activity of G. africana against Candida albicans and Candida glabrata preformed biofilm formation and its antibiofilm activity were tested using the xCELLigence system, which monitors biofilm formation in real time using impedance.

RESULTS: Presence of G. africana resulted in a dose-dependent decrease in Candida biofilms and was found to be effective in the prevention of Candida biofilm formation and disruption of the existing Candida biofilms.

CONCLUSION: The xCELLigence impedance-based system proved to be an effective tool for medication screening. To the best of our knowledge, this is the first reported study to use real-time monitoring of a medicinal plant on microbial biofilm formation.

RevDate: 2025-06-30

Dinelli RG, Shibli JA, Tolentino PHMP, et al (2025)

5-Aminolevulinic Acid Gel Associated with Light-Emitting Diode Modulates the in Vitro Subgingival Multispecies Oral Biofilm.

Photobiomodulation, photomedicine, and laser surgery [Epub ahead of print].

Objective: This study assessed the impact of a 5% combination of 5-aminolevulinic acid (5-ALA) (Aladent) in a multispecies in vitro biofilm model subgingival pathogens. Methods: The 33-species biofilm model was established in the Calgary Biofilm Device during a duration of 7 days. The biofilm treatments comprised various groups: control, light-emitting diode (LED), Aladent (ALADA), and Aladent with LED (ALAD+L), administered on day 6. The Aladent was in contact with the biofilm for 45 min before to the 7-min LED treatment. The LED (λ = 630 nm, power ≈ 380 mW/cm[2]) was placed 2 mm from the biofilm. Subsequently, during 7 days of biofilm formation, the metabolic activity of the biofilms was assessed utilizing triphenyltetrazolium chloride, and the presence of 33 bacterial species was evaluated through DNA-DNA hybridization. Results: The findings indicated that the ALAD+L treatment was the sole intervention demonstrating a statistically significant reduction (∼70%) in the metabolic activity of the biofilms relative to the control group. Moreover, ALAD+L markedly diminished the overall biofilm count and the average counts of five bacterial species: S. intermedius, V. parvula, A. israelii, P. gingivalis, and E. saburreum. Conclusion: The integration of the photosensitizer Aladent with LED application significantly diminished metabolic activity and bacterial species count in the multispecies subgingival biofilm model, indicating substantial promise for the treatment of peri-implantitis.

RevDate: 2025-07-02

Yu D, He J, Zhang X, et al (2025)

Biofilm penetrating and disrupting polymers to effectively treat endotracheal-tube-associated biofilm infections.

Acta biomaterialia pii:S1742-7061(25)00473-8 [Epub ahead of print].

Endotracheal-tube-associated biofilm infections (ETTABIs) are directly responsible for most of ventilator-associated pneumonia (VAP), one of the most frequent ICU-acquired infections with up to 13% mortality rates. Herein, we report a new type of biofilm penetrating and disrupting polymers that can be readily used to effectively treat the ETTABIs. A series of mixed-charge brush polymers with dextran main-chains and random copolypeptide side-chains (e.g., Dex-GnEm) were synthesized by a combination of ring-opening polymerization and side-chain or end-group modifications. The effects of α-amino-acid residue compositions, cationic species, and brush-like topological structures on antibiofilm activities were revealed. The top-performing polymer, namely Dex-G15E15 with equivalent guanidinium-modified L-lysine and L-glutamic acid residues showed efficient biofilm penetrating activity significantly outperforming its cationic polymer counterpart. It also showed potent biofilm disrupting activity that over 90% biofilm can be readily eradicated within 24 h. The majority of the bacteria in the biofilms were killed by a membrane disruption mechanism. In addition, Dex-G15E15 could eradicate biofilms formed in endotracheal tubes, inhibit lung infections, and reduce inflammatory responses in a mouse endotracheal intubation model. This work provides a promising antibiofilm reagent candidate to efficiently treat ETTABIs and VAP. STATEMENT OF SIGNIFICANCE: Endotracheal-tube-associated biofilm infections (ETTABIs) present a major challenge in critical care settings, driving persistent infections, antimicrobial resistance, and ventilator-associated pneumonia. Conventional antimicrobial strategies often fail to penetrate biofilms or inadvertently promote bacterial adaptation. Herein, we developed a biofilm penetrating and disrupting polymer to effectively treat ETTABIs. The polymer with brush-like structure and mixed-charge side-chain showed potent biofilm eradication efficacy by efficient penetrating the biofilm, disrupting both biofilm EPS and bacterial membranes, outperforming conventional antibiotics (e.g., ceftazidime, tobramycin, and ciprofloxacin) and linear or brush-like cationic polymers. It also showed potent inhibition of lung infections and reduction of inflammatory responses in a mouse endotracheal intubation model, making it a promising candidate to combat the ETTABIs.

RevDate: 2025-06-28

Camilo Pattini V, de Assis L, Almeida MTG, et al (2025)

2-Hydroxy-dibenzylideneacetone as a multifunctional coating inhibiting biofilm formation of Candida albicans.

Journal of applied microbiology pii:8172004 [Epub ahead of print].

AIM: Candida albicans emerges as an opportunistic fungus among nosocomial infections, which can include sepsis, bloodstream infections and infections-associated with medical devices. Therefore, we investigated the effectiveness of 2-hydroxy-dibenzylideneacetone, a monocarbonyl curcuminoid as an antifouling-coating against C. albicans.

METHODS AND RESULTS: Polystyrene (hydrophobic) and glass (hydrophilic) were used to study the influence of a curcuminoid-coating on biofilm formation. Fourier-transform-infrared-spectroscopy spectra indicated a successful curcuminoid coating on both surfaces. Atomic-force-microscopy data showed that the curcuminoid-coating on polystyrene decreased the adhesion strength of C. albicans, but had minimal effect on glass. Hyphal growth, a key virulence factor, was significantly reduced on both coated-surfaces. Biofilm formation was significantly reduced on coated polystyrene, but not on glass. Gene expression revealed downregulation of adhesion and biofilm-related genes (HWP1, ALS3, ALS5). Exposure of a 48-h biofilm to curcuminoid decreased the metabolic activity of the biofilm. The curcuminoid coating was biocompatible and non-cytotoxic against human oral keratinocytes and human gingival fibroblasts.

CONCLUSIONS: This study underscores the potential of a curcuminoid-coating to prevent C. albicans adhesion, reduced hyphal and biofilm formation, and reduced metabolic activity of biofilms, highlighting its potential use as an antifouling coating against Candida-associated infections.

RevDate: 2025-06-28

Tran PN, Michalczyk AA, Catubig RA, et al (2025)

Corrosion of AISI 1030 mild steel is influenced by bacteria type, oxygen availability and biofilm formation under controlled laboratory conditions.

Journal of applied microbiology pii:8172001 [Epub ahead of print].

AIM: Bacteria are reported to have both stimulatory and inhibitory effects on the corrosion of metal. To investigate this, we measured corrosion of AISI 1030 mild steel by four species of bacteria: P. aeruginosa, Lelliottia WAP21, B. subtilis and E. cloacae in cultures with normal and restricted access to O2.

METHODS AND RESULTS: Scanning electron microscopy, three-dimensional profilometry and inductively coupled plasma-mass spectrometry were used to measure corrosion. Under aerobic conditions, all four bacterial strains protected the metal surface from pit formation compared with abiotic cultures, most likely through the formation of a biofilm that restricting oxygen access. In contrast, in low-oxygen environments, bacteria caused greater surface corrosion and biofilm formation. Specifically, Lelliottia WAP21 caused corrosion pits more than ten times deeper than those in abiotic cultures and 18-fold more Fe release relative to abiotic controls. Biofilm structures varied with oxygen availability, with each bacterial strain producing distinct biofilms with different elemental composition compared with the abiotic corrosion products. The O2 utilisation in the presence of metal may be related to bacterial metabolic activities including biofilm formation. The presence of Fe was metabolically favourable for bacteria and stimulated growth particularly in low O2 conditions.

CONCLUSION: Our findings show species-specific effects of bacteria on corrosion, where bacterial activity can either enhance or inhibit corrosion depending on oxygen availability.

RevDate: 2025-06-28

Xiong S, Zhang N, Sun H, et al (2025)

LtrA is critical for biofilm formation and colonization of Vibrio parahaemolyticus on food-related surfaces.

International journal of food microbiology, 441:111327 pii:S0168-1605(25)00272-7 [Epub ahead of print].

Vibrio parahaemolyticus is the leading causative agent of seafood-associated acute gastroenteritis. The formation of biofilms is one of the key reasons for its resistance to adverse environments and its persistence in seafood. Investigating the regulatory mechanisms of biofilm formation is beneficial for the development of new intervention methods to reduce V. parahaemolyticus contamination during seafood processing and storage. In this study, we identified a global regulator, LtrA (VPA0519), which is involved in regulating biofilm formation in V. parahaemolyticus. The deletion of ltrA led to a significant alteration in the transcription levels of 706 genes, including those associated with type III and VI secretion systems and biofilm formation. LtrA positively regulated biofilm formation by enhancing the production of exopolysaccharides, extracellular proteins, extracellular DNA, and cyclic di-GMP (c-di-GMP), as well as by decreasing swimming and swarming motility. The deletion of the ltrA gene also led to a reduction in the metabolic activity of biofilm cells but did not affect the production of capsular polysaccharide. Furthermore, the deletion of the ltrA gene resulted in a decrease in the biofilm formation ability of V. parahaemolyticus on the surfaces of shrimp (Parapenaeopsis hardwickii), crab (Portunus trituberculatus), polypropylene plastic, glass, and stainless steel. The findings in this study extend our understanding of the roles of LtrA and the genetic determinants involved in biofilm formation by V. parahaemolyticus.

RevDate: 2025-06-27

Shao S, Liu J, Pan D, et al (2025)

New insight on nitrogen and phosphorus removal of moving bed biofilm reactor driven by ferromanganese binary oxide: Performances and mechanisms.

Bioresource technology pii:S0960-8524(25)00857-0 [Epub ahead of print].

The moving bed biofilm reactor with different iron-manganese ratios was developed to treat the simulated domestic wastewater with a low carbon-to-nitrogen ratio. The result showed that NH4[+]-N and NO3[-]-N of 96 ± 2 % and 55 ± 5 %, 97 ± 1 % and 34 ± 6 %, and 40 ± 5 % and 75 ± 4 % were removed in phases II-IV, and phosphorus removal included adsorption of biological iron and manganese oxides and biological removal. Ferromanganese binary oxide stimulated the extracellular polymeric substances secretion, and dissolved organic matter accelerated the iron-manganese redox cycling. Furthermore, fate of manganese and iron was explored, indicating that location of iron-manganese redox cycling was mainly outside the cells. Specific mechanism of iron-manganese redox cycling driven nitrogen and phosphorus removal was clarified including biofilm community. In conclusion, iron-manganese redox cycling reduced the reactive oxygen species level, and Proteobacteria and Planctomycetota were the dominant genera for nutrient, Fe(II), and Mn(II) removal. This study provides a novel method for efficient removal of nutrients.

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In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

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In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

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Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

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In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

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With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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This is a must read book for anyone with an interest in invasion biology. The full title of the book lays out the author's premise — The New Wild: Why Invasive Species Will Be Nature's Salvation. Not only is species movement not bad for ecosystems, it is the way that ecosystems respond to perturbation — it is the way ecosystems heal. Even if you are one of those who is absolutely convinced that invasive species are actually "a blight, pollution, an epidemic, or a cancer on nature", you should read this book to clarify your own thinking. True scientific understanding never comes from just interacting with those with whom you already agree. R. Robbins

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin and even a collection of poetry — Chicago Poems by Carl Sandburg.

Timelines

ESP now offers a large collection of user-selected side-by-side timelines (e.g., all science vs. all other categories, or arts and culture vs. world history), designed to provide a comparative context for appreciating world events.

Biographies

Biographical information about many key scientists (e.g., Walter Sutton).

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 28 JUL 2024 )