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Bibliography on: Biofilm

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ESP: PubMed Auto Bibliography 12 Apr 2025 at 01:40 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: 2025-04-10

Inokuchi T, Tomiyama K, Okuda T, et al (2025)

Phellodendron bark extract and berberine chloride suppress microbiome dysbiosis in a saliva-derived in vitro microcosm biofilm model.

Archives of oral biology, 174:106231 pii:S0003-9969(25)00059-7 [Epub ahead of print].

OBJECTIVE: Preventing oral microbiome dysbiosis is crucial for averting the onset and progression of periodontal diseases. Phellodendron bark extract (PBE) and its active component berberine exhibit antibacterial properties against periodontal pathogenic bacteria. Although they inhibit Porphyromonas gingivalis (P. gingivalis)-induced dysbiosis in vitro in multiple species of saliva-derived planktonic cultures, their effects on microcosm biofilm models remain unclear. In this study, we aimed to elucidate the dysbiosis-suppressive effects of PBE and berberine chloride (BC) on biofilm formation.

DESIGN: PBE or BC was added during the formation of in vitro microcosm biofilms containing saliva and P. gingivalis, which were anaerobically cultured for one week. Next-generation sequencing was performed to assess microbiota composition, while quantitative real-time PCR was used to measure bacterial concentrations. Additionally, the butyrate concentration in the culture supernatant was assessed as biofilm pathogenicity.

RESULTS: PBE and BC treatments reduced the relative abundance of periodontal pathogenic bacteria, including P. gingivalis, and significantly increased the relative abundance of the genus Streptococcus and nitrate-reducing bacteria, including the genera of Neisseria and Haemophilus. Moreover, the treatment groups exhibited significantly decreased butyrate concentrations.

CONCLUSIONS: Our findings suggest that PBE and BC could suppress dysbiosis triggered by P. gingivalis in microcosm biofilms in vitro by decreasing the relative abundance and amount of periodontal pathogenic bacteria and enhancing those of nitrate-reducing bacteria that have a high relative abundance in orally healthy individuals. In summary, PBE and BC may contribute to the prevention of periodontal disease through their dysbiosis-suppressive and anti-inflammatory effects.

RevDate: 2025-04-10

Abdallah M, Greige S, Webster CF, et al (2025)

Enhancement of the start-up and performance of an upflow anaerobic sludge blanket (UASB) reactor using electrochemically-enriched biofilm.

Enzyme and microbial technology, 188:110651 pii:S0141-0229(25)00071-7 [Epub ahead of print].

A novel approach was developed to accelerate the start-up of a 20-L UASB reactor under mesophilic conditions. Two runs were conducted, where the first run (Run I) was inoculated with anaerobic sludge, and the second run (Run II) was inoculated with the same sludge supplemented with enriched electro-active biofilms collected from the working and counter electrodes of anodic and cathodic bio-electrochemical systems (BESs). Reactors' performance and microbial dynamics were monitored over 41 days. Methane production in Run II exceeded 200 mL-CH4/g-COD within 10 days, compared to 29 days in Run I. Run II achieved 80 % removal of soluble COD after 13 days as compared to 23 days in Run I. Sludge washout in Run II stabilized after 3 days, achieving 70 % VSS removal, whereas Run I required 17 days. Greater extracellular polymeric substance (EPS) values and higher protein-to-polysaccharide ratios in Run II may indicate accelerated granules formation mediated by EPS. 16S rRNA gene sequencing analysis results revealed shared genera between both runs but different relative abundances. Methanothrix dominated in Run I, while other archaeal genera, mainly Methanosarcina and Methanobacterium increased in abundance in the Run II. The Enterobacteriaceae family was prevalent in both reactors, with three genera, Citrobacter, Klebsiella, and Enterobacter distinctly dominating at different time points, suggesting potential links with the initial seed sludge or enriched biofilm consortia. The addition of electrochemically grown biofilm in Run II likely enhanced the microbial diversity, contributed to the rapid development of granular syntrophic communities, and improved reactor performance.

RevDate: 2025-04-10
CmpDate: 2025-04-10

Abdeljelil N, Chatti A, Gillan D, et al (2025)

Antimicrobial applications of inorganic radiosensitizers and their potential in biofilm control.

World journal of microbiology & biotechnology, 41(4):130.

Biofilms are structured microbial communities embedded in a self-produced extracellular matrix. This lifestyle provides significant protection against environmental stressors such as desiccation, chemical treatments and even ionizing radiation. Radiation, while a well-established antibacterial strategy, can be less effective in biofilms. Biofilm superior resilience is due to several advantages such as the shielding provided by the matrix, the metabolic heterogeneity and adaptive stress responses of biofilm-associated cells. To address this challenge, researchers are increasingly employing combination strategies in antibiofilm treatment. Radiosensitizers, compounds originally developed to enhance the efficacy of radiation therapy in cancer treatment, have also garnered attention for their potential in antimicrobial applications. These compounds act by amplifying the effects of radiation, often through mechanisms such as increased oxidative stress or inhibition of DNA repair pathways. However, research on radiosensitizers in bacterial systems has focused on planktonic cultures, with limited studies exploring their effects on biofilms. Given the complexity and unique characteristics of biofilms, their response to radiosensitization remains poorly understood and requires further investigation. The use of radiosensitizers in conjunction with radiation presents a promising approach to overcome the inherent resilience of biofilms. By enhancing the susceptibility of biofilm-associated bacteria to radiation and simultaneously disrupting their protective structures, such approaches could lead to more effective and comprehensive solutions. Understanding the nuanced responses of biofilms to these combined treatments is essential for advancing both medical and environmental applications and addressing the challenge of biofilm persistence.

RevDate: 2025-04-10

Yang Y, Yan J, Olson R, et al (2025)

Comprehensive genomic and evolutionary analysis of biofilm matrix clusters and proteins in the Vibrio genus.

mSystems [Epub ahead of print].

UNLABELLED: Vibrio cholerae pathogens cause cholera, an acute diarrheal disease resulting in significant morbidity and mortality worldwide. Biofilms in vibrios enhance their survival in natural ecosystems and facilitate transmission during cholera outbreaks. Critical components of the biofilm matrix include the Vibrio polysaccharides produced by the vps-1 and vps-2 gene clusters and the biofilm matrix proteins encoded in the rbm gene cluster, together comprising the biofilm matrix cluster. However, the biofilm matrix clusters and their evolutionary patterns in other Vibrio species remain underexplored. In this study, we systematically investigated the distribution, diversity, and evolution of biofilm matrix clusters and proteins across the Vibrio genus. Our findings reveal that these gene clusters are sporadically distributed throughout the genus, even appearing in species phylogenetically distant from Vibrio cholerae. Evolutionary analysis of the major biofilm matrix proteins RbmC and Bap1 shows that they are structurally and sequentially related, having undergone structural domain and modular alterations. Additionally, a novel loop-less Bap1 variant was identified, predominantly represented in two phylogenetically distant V. cholerae subspecies clades that share specific gene groups associated with the presence or absence of the protein. Furthermore, our analysis revealed that rbmB, a gene involved in biofilm dispersal, shares a recent common ancestor with Vibriophage tail proteins, suggesting that phages may mimic host functions to evade biofilm-associated defenses. Our study offers a foundational understanding of the diversity and evolution of biofilm matrix clusters in vibrios, laying the groundwork for future biofilm engineering through genetic modification.

IMPORTANCE: Biofilms help vibrios survive in nature and spread cholera. However, the genes that control biofilm formation in vibrios other than Vibrio cholerae are not well understood. In this study, we analyzed the biofilm matrix gene clusters and proteins across diverse Vibrio species to explore their patterns and evolution. We discovered that these genes are spread across different Vibrio species, including those not closely related to V. cholerae. We also found various forms of key biofilm proteins with different structures. Additionally, we identified genes involved in biofilm dispersal that are related to vibriophage genes, highlighting the role of phages in biofilm development. This study not only provides a foundational understanding of biofilm diversity and evolution in vibrios but also leads to new strategies for engineering biofilms through genetic modification, which is crucial for managing cholera outbreaks and improving the environmental resilience of these bacteria.

RevDate: 2025-04-10
CmpDate: 2025-04-10

Lopez Avila F, Capps KA, RL Bier (2025)

Surface Texture of Macroplastic Pollution in Streams Alters the Physical Structure and Diversity of Biofilm Communities.

Environmental microbiology reports, 17(2):e70068.

Biofilms can develop on nearly any surface, and in aquatic ecosystems they are essential components of biogeochemical cycles and food webs. Plastic waste in waterways is a new type of surface for biofilm colonisation. To analyse the influence of plastic pollution on the development and diversity of microbial freshwater biofilms that colonised them, we incubated 388 cm[2] veneers of high-density polyethylene (HDPE) with two veneer textures, smooth and rough, and tulip tree wood (Liriodendron tulipifera), in three rural headwater streams at the Savannah River Site (Aiken, SC, USA). We collected biofilms from veneers after 14, 28 and 56 days of incubation and analysed 16S rRNA genes and biofilm properties. We found that plastic negatively affected species richness of biofilms compared with wood, but that evenness was greatest on rough textured HDPE. Beta diversity was primarily influenced by stream site. Beta diversity differed more between wood and plastic veneers than with plastic surface texture and became more different over time. Wood had nine times more biomass than rough HDPE and 40 times more biomass than smooth HDPE. Given the projected increase of macroplastic pollution in aquatic ecosystems, our findings emphasise the need to further understand its effects on biofilm characteristics.

RevDate: 2025-04-11
CmpDate: 2025-04-09

Al-Maddboly LA, El-Salam MA, Bastos JK, et al (2025)

Anti-biofilm and anti-quorum sensing activities of galloylquinic acid against clinical isolates of multidrug-resistant Pseudomonas aeruginosa in open wound infection: in vitro and in vivo efficacy studies.

BMC microbiology, 25(1):206.

BACKGROUND: Pseudomonas aeruginosa can proliferate in immunocompromised individuals, forming biofilms that increase antibiotic resistance. This bacterium poses a significant global health risk due to its resistance to human defenses, antibiotics, and various environmental stresses. The objective of this study was to evaluate the antibacterial, anti-biofilm, and anti-quorum sensing activities of galloylquinic acid compounds (GQAs) extracted from Copaifera lucens leaves against clinical isolates of multidrug-resistant (MDR) P. aeruginosa. We have investigated the optimal concentration of GQAs needed to eradicate preexisting biofilms and manage wound infections caused by P. aeruginosa, in vitro and in vivo.

RESULTS: Our results revealed that GQAs exhibited 25-40 mm inhibition zone diameters, with 1-4 µg/mL MIC and 2-16 µg/mL MBC values. GQAs interfered with the planktonic mode of P. aeruginosa isolates, and significantly inhibited their growth in the pre-formed biofilm architecture, with MBIC80 and MBEC80 values of 64 µg/mL and 128 µg/mL, respectively. The anti-biofilm effect was confirmed by fluorescence staining and confocal microscopy which showed a dramatic reduction in the cell viability and the biofilm thickness (62.5%), after exposure to 128 µg/mL of GQAs in particular. The scanning electron micrographs showed that GQAs impaired biofilm and bacterial structures by interfering with the biomass and the exopolysaccharides forming the matrix. GQAs also interfered with virulence factors and bacterial motility, where 128 µg/mL of GQAs significantly (p < 0.05) reduced rhamnolipid, pyocyanin, and the swarming motility of the organism which play a vital role in the biofilm formation. GQAs downregulated 89% of the quorum-sensing genes (lasI and lasR, pqsA and pqsR) involved in the biofilm formation.

CONCLUSION: GQAs demonstrate significant promise as novel and potent antibiofilm and antivirulence agents against clinical isolates of MDR P. aeruginosa, with substantial potential to enhance wound healing in biofilm-associated infections. This promising antibacterial action positions GQAs as a superior alternative for the treatment of biofilm-associated wound infections, with substantial potential to improve wound healing and mitigate the impact of persistent bacterial infections.

CLINICAL TRIAL NUMBER: not applicable.

RevDate: 2025-04-09

Song G, Bi Z, Liu Y, et al (2025)

Influence of operation sequences on phosphorus ennrichment by polyphosphate accumulating organisms biofilm: performance, phosphorus transfer and phosphate metabolism in biofilm.

Environmental research pii:S0013-9351(25)00811-4 [Epub ahead of print].

This study investigated the impact of different operational sequences on phosphorus removal and enrichment in biofilm phosphorus enrichment system. The research com-pared two distinct operational modes, analyzing phosphorus uptake and release characteristics in cells and extracellular polymeric substances (EPS) over a single cycle, while also examining microbial community composition and associated functional genes. After long-term acclimation, the Ae/An system achieved higher phosphorus concentration (120 mg/L) than the An/Ae system (65 mg/L). However, the An/Ae system showed stronger phosphorus uptake and release capabilities due to higher phosphorus load during the aerobic phase. In both systems, Mg-P and Ca-P dominated in cells and EPS. Compared to the Ae/An system, the An/Ae system stored phosphorus mainly in EPS, with higher orthophosphate content. However, EPS-associated phosphorus is more easily released, explaining the An/Ae system's higher aerobic phosphorus load but lower overall storage capacity. Microbial analysis revealed higher abundance of phosphorus accumulating organisms (PAOs) in the An/Ae system (25.99% vs. 19.69%), while glycogen accumulating organisms (GAOs) showed the opposite trend. Candidatus Competibacter was abundant in both systems and correlated with phosphorus metabolism genes. The An/Ae system expressed the pst system more, whereas the Ae/An favored the pit system, suggesting that transfer system variations affect enrichment solution concentration. Lower expression of polyphosphate kinase (ppk1) in the An/Ae system may explain its unstatisfied phosphorus enrichment performance. Mantel analysis confirmed connections among environmental factors, kinetic parameters, phosphorus metabolism genes, and phosphorus morphology in EPS, demonstrating their combined influence on enrichment solution concentration.

RevDate: 2025-04-08

Qin S, Lin Y, Yang C, et al (2025)

Comparison of the start-up of rotating biofilm contactor reactor with HN-AD bacteria inoculation under high and low influent ammonia conditions.

Journal of environmental management, 381:125206 pii:S0301-4797(25)01182-X [Epub ahead of print].

Biofilm formation is critical for the engineering application of pure biofilm RBC processes inoculated with HN-AD bacteria. This study focused on comparing the startup of pure biofilm RBC systems inoculated with HN-AD bacteria under high ammonia nitrogen (NH4[+]-N = 500 mg/L, H-RBC) and low ammonia nitrogen (NH4[+]-N = 120 mg/L, L-RBC) influent conditions. The results showed that H-RBC shortened the biofilm formation time by 6 days. Additionally, the average removal efficiencies of ammonia nitrogen and TN were 30.70 % and 38.98 % higher than those of L-RBC, respectively. High-throughput sequencing indicated that compared with L-RBC, H-RBC did not significantly change the types of HN-AD bacteria but significantly increased the abundance of the key HN-AD bacterial genera Planktosalinus and Corynebacterium. Functional gene prediction analysis showed that the abundance of key functional genes affecting the nitrogen removal process, nirS and nosZ, in H-RBC was significantly higher than in L-RBC. Phenotypic prediction analysis revealed that H-RBC could better resist changes in the external environment and had stronger nitrogen removal capacity. These findings provide a theoretical basis and effective approach for the start-up of pure biofilm RBC system.

RevDate: 2025-04-08
CmpDate: 2025-04-08

Zhang P, Yang H, Ahmad MT, et al (2025)

Integrating Modified Fe3O4 Nanoparticles and Nisin with T4 Bacteriophage for Enhanced Biofilm Eradication.

Current microbiology, 82(6):237.

Biofilm formation presents significant challenges in healthcare, food processing, and water treatment, contributing to antibiotic resistance and persistent infections. Effective strategies to combat biofilm-associated infections are urgently needed. This study introduces a novel approach to biofilm removal by bio-functionalizing T4 bacteriophage with modified Fe3O4 nanoparticles (NPs) and Nisin, an antibacterial peptide, to form the Fe3O4-Phage-T4 + Nisin complex. The aim is to enhance antimicrobial efficacy and biofilm eradication. The Fe3O4-Phage-T4 + Nisin complex was synthesized by conjugating T4 bacteriophage with modified Fe3O4 NPs and Nisin. The antimicrobial and antibiofilm activity of the complex was evaluated against multidrug-resistant Pseudomonas aeruginosa strains (PA01 and PA14) using biofilm inhibition and eradication assays. Stability and efficacy were further tested across a pH range of 5 to 8. The Fe3O4-Phage-T4 + Nisin complex exhibited superior biofilm removal compared to its individual components. The integration of Nisin broadened the antibacterial spectrum, targeting both Gram-positive and Gram-negative bacteria, while the modified Fe3O4 NPs enhanced phage penetration and bacterial cell disruption. The complex demonstrated significant biofilm inhibition and eradication, addressing the challenge of biofilm-related antibiotic tolerance, which often necessitates high antibiotic doses. Additionally, it maintained stability and efficacy across varying pH conditions.

RevDate: 2025-04-08

Dash SK, Marques CNH, GJ Mahler (2025)

Small Intestine on a Chip Demonstrates Physiologic Mucus Secretion in the Presence of Lacticaseibacillus rhamnosus Biofilm.

Biotechnology and bioengineering [Epub ahead of print].

The small intestine is an area of the digestive system difficult to access using current medical procedures, which prevents studies on the interactions between food, drugs, the small intestinal epithelium, and resident microbiota. Therefore, there is a need to develop novel microfluidic models that mimic the intestinal biological and mechanical environments. These models can be used for drug discovery and disease modeling and have the potential to reduce reliance on animal models. The goal of this study was to develop a small intestine on a chip with both enterocyte (Caco-2) and goblet (HT29-MTX) cells cocultured with Lacticaseibacillus rhamnosus biofilms, which is of one of several genera present in the small intestinal microbiota. L. rhamnosus was introduced following the establishment of the epithelial barrier. The shear stress within the device was kept in the lower physiological range (0.3 mPa) to enable biofilm development over the in vitro epithelium. The epithelial barrier differentiated after 5 days of dynamic culture with cell polarity and permeability similar to the human small intestine. The presence of biofilms did not alter the barrier's permeability in dynamic conditions. Under fluid flow, the complete model remained viable and functional for more than 5 days, while the static model remained functional for only 1 day. The presence of biofilm increased the secretion of acidic and neutral mucins by the epithelial barrier. Furthermore, the small intestine on a chip also showed increased MUC2 production, which is a dominant gel-forming mucin in the small intestine. This model builds on previous publications as it establishes a stable environment that closely mimics in vivo conditions and can be used to study intestinal physiology, food-intestinal interactions, and drug development.

RevDate: 2025-04-10
CmpDate: 2025-04-07

Ware A, Johnston W, Delaney C, et al (2025)

Dry Surface Biofilm Formation by Candida auris Facilitates Persistence and Tolerance to Sodium Hypochlorite.

APMIS : acta pathologica, microbiologica, et immunologica Scandinavica, 133(4):e70022.

Candida auris is an enigmatic fungal pathogen, recently elevated as a critical priority group pathogen by the World Health Organisation, linked with its ability to cause outbreaks within nosocomial care units, facilitated through environmental persistence. We investigated the susceptibility of phenotypically distinct C. auris isolates to sodium hypochlorite (NaOCl), and evaluated the role of biofilms in surviving disinfection using a dry-surface biofilm (DSB) model and transcriptomic profiling. Planktonic cells were tested for susceptibility to NaOCl, with biofilm formation using the 12-day DSB model, assessed using viable counts, biomass assays and microscopy. Disinfection efficacy was assessed using clinical protocols of 500-1,000 ppm for 1-5 min. RNA sequencing was performed on untreated DSBs in comparison to planktonic cells. Isolates were found to be susceptible planktonically, but grew NaOCl-tolerant biofilms, with only 2-4 log10 reductions in viable cells observed at highest concentrations. Transcriptomics identified DSB upregulation of ABC transporters and iron acquisition pathways relative to planktonic cells. Our findings optimized a DSB protocol in which C. auris can mediate tolerance to NaOCl disinfection, suggesting a lifestyle through which this problematic yeast can environmentally persist. Mechanistically, it has been shown for the first time that upregulation of small-molecule and iron transport pathways are potential facilitators of environmental survival.

RevDate: 2025-04-07

Yang Y, Li S, Zhou X, et al (2025)

Closed fixed-bed bacteria-algae biofilm reactor: A promising solution for phenol containing wastewater treatment and resource transformation.

Journal of hazardous materials, 492:138176 pii:S0304-3894(25)01091-X [Epub ahead of print].

This study focuses on treating phenolic wastewater with a novel closed fixed-bed bacteria-algae biofilm reactor (CF-BABR) to enhance resource transformation for phenolic substances. The CF-BABR showed strong impact - load resistance and stable degradation efficiency, fully degrading phenolic compounds at concentrations from 0 to 150 mg/L. From the inflow to the outflow, the effective sequences, abundance, and diversity of bacteria decreased. Chlorobaculum was the dominant bacterium for phenolic pollutant degradation. The abundance of fungi decreased gradually, while their diversity increased. Kalenjinia and Cutaneotrichosporon played a synergistic role in reducing pollutant toxicity. The high - concentration pollutants at the influent led to a higher abundance of microalgal communities, and Scenedesmaceae became the most dominant algal family, which was positively correlated with the degradation of phenolic compounds. Functional gene prediction indicated that the abundance of functional genes in bacteria decreased overall along the wastewater flow. Carbohydrate metabolism and amino acid metabolism were the most active secondary pathways. In fungi, the predicted gene functions had the highest abundance in the upstream region. Metabolic intermediates such as organic acids and derivatives, lipids and lipid - like molecules, and carboxylic acids and derivatives demonstrated the degradation effect of CF-BABR on phenolic compounds.

RevDate: 2025-04-07

Bouafia A, Laib I, Laouini SE, et al (2025)

Comprehensive Bioactivities and Phytochemical Profiling of Rumex vesicarius: Antioxidant Potential, Anti-Diabetic Properties, and Anti-Biofilm Effects under Thermal Treatment.

Chemistry & biodiversity [Epub ahead of print].

This study investigates the effect of thermal treatment on the phytochemical composition and bioactivities of Rumex vesicarius, focusing on its antioxidant, antidiabetic, and anti-biofilm properties. Quantitative analysis showed that at ambient temperature, the extract had the highest phenolics (57.89 mg GAE/g), flavonoids (19.45 mg QE/g), tannins (12.78 mg CE/g), flavonols (6.48 mg), and anthraquinones (2.078 mg). At 60°C, it retained significant phenolics (52.89 mg GAE/g) and flavonoids (18.45 mg QE/g) with minimal degradation. At 90°C, phenolics decreased slightly (43.59 mg GAE/g), but enzymatic inhibition and antimicrobial properties improved. β-Carotene stability varied, with untreated extract at IC50 of 118.136 µg/mL. Peak antioxidant activity was at 150°C (IC50 = 102.77 µg/mL), with degradation above 150°C. Antidiabetic potential, via α-amylase and α-glucosidase inhibition, showed lowest IC50 values (92.106 µg/mL for both) at 90°C. Beyond 120°C, IC50 rose to 268.35 µg/mL (α-amylase) and 268.31 µg/mL (α-glucosidase) at 210°C. Anti-biofilm activity peaked at 90°C (IC50 = 33.55 µg/mL), with untreated and 60°C extracts showing strong inhibition (~80-90%). Above 90°C, inhibition dropped, reaching IC50 of 253.53 µg/mL at 210°C. Moderate heating (60°C-90°C) optimizes bioactive availability, positioning R. vesicarius for pharmaceutical and nutraceutical applications.

RevDate: 2025-04-07

Li X, Zhang R, Zhang J, et al (2025)

Harnessing Biofilm Scaffold for Structurally Adaptative Slippery Surfaces with Integrated Antifouling and Anti-Corrosion Properties.

Angewandte Chemie (International ed. in English) [Epub ahead of print].

Artificial liquid-repellent surfaces are highly desirable to combat pervasive biofouling and corrosion in biological environments. However, existing strategies often suffer from slow binding kinetics and harsh fabrication conditions, hindering the concurrent integration of liquid repellency, universal adhesion, and robust flexibility. Herein, we report that it is possible to engineer microbial biofilms as eco-friendly, cohesive, and flexible materials for omniphobic slippery coatings fulfilling all these requirements. Unlike conventional synthetic slippery coatings requiring laborious surface pretreatments, biofilm sheets formed on demand assemble a durable nanotextured framework on diverse substrates with multiple material categories and surface topologies, serving as hydrophobic lubricant reservoirs. Employing this renewable material enables the scalable and sustainable coating production. The resulting optically transparent and highly flexible coatings manifest exceptional self-cleaning properties, readily shedding both waterborne and oily liquids over a broad viscosity range. Notably, the synergy between the corrosion-protective extracellular matrix and non-stick slipping motion confers unprecedented anti-biofouling efficacy and corrosion resistance. This study offers a distinctive perspective on harnessing ubiquitous native biofilms as biomaterials for self-adaptive coatings, facilitating tailored functionality across broad applications.

RevDate: 2025-04-08

Atencio B, Malavin S, Rubin-Blum M, et al (2025)

Site-specific incubations reveal biofilm diversity and functional adaptations in deep, ancient desert aquifers.

Frontiers in microbiology, 16:1533115.

Deep pristine aquifers are ecological hotspots with diverse microbial life, where microorganisms exist either attached (sessile) to solid substrates or suspended in groundwater (planktonic). Characterizing the attached microbial communities is of paramount importance, especially in the context of biofouling. However, obtaining samples of attached microbes that thrive under natural (undisturbed) conditions is challenging. Our study addresses this by retrieving sessile microbes on-site. We installed columns filled with site-specific rock cuttings at the wellhead, allowing fresh groundwater to flow continuously for approximately 60 days. We hypothesized that the attached microbial communities would differ structurally from planktonic microbes due to the aquifer's lithological and mineralogical composition. This study involved an exploratory examination of the microbial communities in different aquifers with distinct mineralogies, including quartzitic sandstone, calcareous, chert, and highly heterogeneous (clastic) aquifers in Israel's Negev Desert. Metagenomic analysis revealed both shared and distinct microbial communities among attached and planktonic forms in the various environments, likely shaped by the aquifers' physical, lithological, and mineralogical properties. A wealth of carbon-fixation pathways and energy-conservation strategies in the attached microbiome provide evidence for the potential productivity of these biofilms. We identified widespread genetic potential for biofilm formation (e.g., via pili, flagella, and extracellular polymeric substance production) and the interactome (e.g., quorum-sensing genes). Our assessment of these functions provides a genomic framework for groundwater management and biofouling treatment.

RevDate: 2025-04-06
CmpDate: 2025-04-06

Fathima SA, Arafath AY, Prathiviraj R, et al (2025)

Bioactive Fraction of Streptomyces thinghirensis MSA1 Effectively Inhibits Biofilm Forming Clinically Significant AMR Pathogens.

Current microbiology, 82(6):234.

The escalating threat of antibiotic-resistant microorganisms necessitate the discovery of novel antibacterial agents. This study explores the potential of marine-associated actinomycetes, focusing on Streptomyces thinghirensis MSA1, isolated from the marine sponge Callyspongia diffusa in Palk Bay, India, for its notable antibacterial properties. To optimize the production of bioactive compounds of S. thinghirensis MSA1, we established optimal growth conditions (30 °C, pH 7, 2% salinity, 9-day incubation) and utilized ISP4 medium for enhanced secondary metabolite production. The extracted compound, MSA1, was analyzed through FTIR and GCMS, identifying 20 biologically active components. MSA1 demonstrated potent antibacterial activity against significant pathogens, including Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa, and MRSA, alongside remarkable antioxidant and anti-biofilm properties. These findings highlight the potential of MSA1 as a promising candidate for developing treatments against antibiotic-resistant infections. This study acknowledges the preliminary nature of the findings and the necessity for further in vivo and clinical trials to fully ascertain the therapeutic potential of MSA1. This research opens avenues for novel antibacterial agents in the fight against antibiotic resistance, underscoring the value of marine biodiversity in medical science.

RevDate: 2025-04-05

Qu Y, Gao C, Li R, et al (2025)

Synthesis and antimicrobial evaluation of novel quaternary quinolone derivatives with low toxicity and anti-biofilm activity.

European journal of medicinal chemistry, 291:117591 pii:S0223-5234(25)00356-3 [Epub ahead of print].

To overcome the increasing global drug resistance, the development of novel antimicrobial drugs is a top priority in the fight against multidrug resistant (MDR) and persistent bacteria. In this work, we report the synthesis of novel single quaternary quinolone antibacterial agents. The majority of the tested compounds exhibited significant antimicrobial efficacy against Gram-negative pathogens (E. coli and S. maltophilia). Notably, the selected compound (4e) was highly inhibitory with a MIC value of 0.25 μg/mL against E. coli. Additionally, compound 4e demonstrated excellent stability in complex biological fluids with low hemolytic activity (HC50 > 1280 μg/mL) and a significantly lower propensity to induce bacterial resistance. Encouragingly, 4e showed not only rapid bactericidal activity and inhibition of bacterial biofilms, but also low toxicity to erythrocytes and RAW 264.7 cells compared to the clinical drug ciprofloxacin. Mechanism studies have found that compound 4e has a relatively weak destructive effect on the cell membrane of E. coli. However, it can effectively inhibit the activity of glutathione (GSH), promote the massive accumulation of intracellular reactive oxygen species (ROS), and then disrupt the antioxidant defense system of bacteria, achieving a bactericidal effect. In addition, compound 4e has a certain binding effect with bacterial DNA.

RevDate: 2025-04-05
CmpDate: 2025-04-05

Adhikary R, Sarkar I, Patel D, et al (2025)

Deciphering antibiotic resistance, quorum sensing, and biofilm forming genes of Micrococcus luteus from hemodialysis tunneled cuffed catheter tips of renal failure patients.

Archives of microbiology, 207(5):114.

Catheter-related bloodstream infections create a significant challenge in healthcare system, often complicated by antibiotic resistance and biofilm formation of multi-drug resistance and virulent bacterial pathogens. This study focused on biofilm-forming efficiency, and underlying genetic mechanisms in Micrococcus luteus HL_Chru_C3, isolated from a hemodialysis catheter tip. The isolate exhibited resistance to multiple antibiotic classes, including beta-lactams and glycopeptides. Biofilm assays revealed that M. luteus HL_Chru_C3 formed optimum biofilms at high concentration of carbohydrates (500 mM), and pH 5 but there was no significant role of mineral salts. Whole-genome sequencing and bioinformatic analysis using CARD, KAAS, and KEGG databases identified genes associated with antibiotic resistance (ftsI, pbp1a/2, vanY, alr, ddl, murF, mraY, and murG), quorum sensing (genes from the opp family, sec, cylA, ccfA, phnA, phnB, phzC, rpfB, clp, and toxE), and biofilm formation (phnA, phnB, cyaB, vfr, vps, glgC, wecB, wecC, and cysE). The predicted mechanisms of action for these genes, based on homology to other organisms, suggest complex interactions contributing to the observed phenotypes. This study provides an insight into the genetic basis of antibiotic resistance and biofilm formation in M. luteus HL_Chru_C3 isolated from a hemodialysis catheter, highlighting the need for effective infection control strategies to combat CRBSIs.

RevDate: 2025-04-05

Berenjian A, Mahdinia E, A Demirci (2025)

Scaling up biofilm bioreactors for enhanced menaquinone-7 production.

Bioprocess and biosystems engineering [Epub ahead of print].

The health benefits of menaquinone-7 (MK-7) are well-established, and its production through fermentation techniques is widespread. Our team developed an innovative biofilm reactor utilizing Bacillus subtilis natto cells to foster biofilm growth on plastic composite supports to produce MK-7. The scalability of this biofilm reactor from a 2-L benchtop scale in our laboratory and its potential for commercial applications pose significant unresolved questions. Therefore, the current research was aimed to scale up the biofilm reactor from bench scale (2-L) to the pilot scale (30-L) bioreactor. Three strategies were evaluated to understand their impact on MK-7 biosynthesis during bioreactor volume expansion: volumetric oxygen mass transfer coefficient (kLa), agitation power input per unit volume (P/V), and impeller tip velocity (Vtip). While kLa was successfully maintained during scaling, P/V and Vtip varied and were assessed for their influence on MK-7 production. After investigating these methods, it was found that the volumetric oxygen mass transfer coefficient (kLa) constant method proved to be the most effective one. The optimum MK-7 concentration achieved was 21.0 ± 1.0 mg/L, comparable to the highest MK-7 concentration of 20.6 ± 1.0 attained at the 2-L scale. This showcases the scalability of biofilm bioreactor technology and its promising potential for commercial production of MK-7. Furthermore, we explored the potential of fed-batch glucose addition to the base media in the biofilm reactor to enhance MK-7 concentration at the 30-L scale. Remarkably, results demonstrated that fed-batch strategy significantly increased MK-7 concentrations to 28.7 ± 0.3 mg/L, which made it almost 2.3-fold higher than levels produced in suspended-cell bioreactors. This finding highlights the potential of biofilm reactors as a promising replacement to the current static fermentation strategies for commercial production of MK-7.

RevDate: 2025-04-07

Yincharoen P, Mordmuang A, Techarang T, et al (2025)

Microbiome and biofilm insights from normal vs tumor tissues in Thai colorectal cancer patients.

NPJ precision oncology, 9(1):98.

Colorectal cancer (CRC) is a prevalent global malignancy with complex etiologies, including microbiota alterations. This study investigates gut microbiota and biofilm-producing bacteria in 35 Thai CRC patients, analyzing paired normal and tumor biopsy samples. Bacterial DNA from the V3-V4 region of 16S rRNA was sequenced, and biofilms were visualized via scanning electron microscopy and fluorescence in situ hybridization (FISH). Results revealed Firmicutes as the dominant phylum, followed by Bacteroidota, Proteobacteria, and Fusobacteriota, with Fusobacteriota and Bacteroidota notably enriched in left-sided CRC. Key biofilm producers-Bacteroides fragilis, Fusobacterium nucleatum, and Pasteurella stomatis-showed significantly higher gene expression in tumor tissues. Dense biofilms and higher Fusobacterium abundance, localized within the crypts of Lieberkuhn, were observed in CRC tissues. These findings highlight CRC-associated microbiota alterations and pathogenic biofilm production, emphasizing a spatial relationship between tumor location and microbial distribution, with potential implications for understanding CRC pathogenesis and therapeutic targeting.

RevDate: 2025-04-04

Caigoy JC, Nariya H, Shimamoto T, et al (2025)

ArcAB system promotes biofilm formation through direct repression of hapR transcription in Vibrio cholerae.

Microbiological research, 297:128155 pii:S0944-5013(25)00111-9 [Epub ahead of print].

Vibrio cholerae, the causative agent of cholera, can efficiently adapt its metabolic processes, including biofilm formation, in response to varying respiratory conditions- such as aerobic, microaerobic, and anaerobic- through the ArcAB system. In this study, we elucidate the activation mechanism of V. cholerae ArcB and ArcA and identify ArcB residues H292, D577, and H722, along with ArcA residue D54 as key phosphorylation sites. Furthermore, we demonstrate that the ArcAB system plays a crucial role in regulating biofilm formation under both aerobic and anaerobic conditions. Our findings reveal that the positive regulation of biofilm formation by the ArcAB systems involves the high cell density (HCD) quorum sensing (QS) regulator HapR. Specifically, phosphorylated ArcA represses hapR transcription, thereby promoting biofilm formation under anaerobic condition. This study also highlights an epistatic relationship between ArcA and HapR in biofilm regulation. Overall, our results underscore the critical role of the ArcAB system in the biofilm formation of pathogenic V. cholerae under oxygen-limiting conditions.

RevDate: 2025-04-04

Liu N, Ostertag-Henning C, Fernø MA, et al (2025)

Growth on Hydrogen by the Sulfate-Reducing Oleidesulfovibrio alaskensis Induces Biofilm Dispersion and Detachment─Implications for Underground Hydrogen Storage.

Environmental science & technology [Epub ahead of print].

Hydrogen is a versatile energy carrier for human activity but is also a ubiquitous electron donor for subsurface microorganisms. During underground hydrogen storage operations, it is expected that microbial communities will use the injected hydrogen as electron donor for diverse metabolisms, and induce a variety of microbial-triggered risks. A significant concern is the formation of biofilm and induced bioclogging, which may reduce the hydrogen injectivity and storage operation efficiency by altering the subsurface hydrogen flow. This study investigates how different electron donors─specifically hydrogen and lactate─affect the growth dynamics of a sulfate-reducing bacterium (Oleidesulfovibrio alaskensis G20) and the associated biofilm formation in porous media. The pore-scale observations reveal that lactate promotes robust biofilms resulting in bioclogging, compared to hydrogen promoting increased microbial motility with less biomass production. Potential hydrogen chemotaxis leads to biofilm dispersal and detachment over time as the cells seemingly favor a planktonic lifestyle over biofilm formation. Multiple hydrogen injections enhanced biofilm detachment and reduced the risk of pore blockage associated with microbial growth. Three hydrogen injections resulted in 69% biofilm detachment, while nitrogen injection caused only 31% detachment over three cycles. The combination of increased cell motility and reduced biofilm attachment indicates that the risk of bioclogging during cyclic UHS operation might be low for this model bacterial strain.

RevDate: 2025-04-05

Chougule S, Patil S, Gavandi T, et al (2025)

Alpha-bisabolol inhibits yeast to hyphal form transition and biofilm development in Candida albicans: in vitro and in silico studies.

In silico pharmacology, 13(1):53.

In recent years, there has been growing concern about infections caused by Candida albicans, which pose a significant threat to human health. This intensifies the concern that can be largely attributed to the increasing number of people with compromised immune systems and the emergence of drug-resistant strains. Natural molecules are considered to be good alternatives to synthetic antifungal agents. The present study explored the effectiveness of alpha-bisabolol as an antifungal agent and its mechanism of action against C. albicans ATCC90028. α-bisabolol effectively inhibited various pathogenic traits of C. albicans like, adhesion, yeast to hyphal switching, and development of biofilm at 1 mg/ml, 0.25 mg/ml, and 0.125 mg/ml concentration, respectively. In addition, α-bisabolol demonstrated inhibition of cell cycle propagation at the G1 phase. Ergosterol production in the C. albicans was suppressed by α-bisabolol treatment in a dose-dependent manner. The molecular docking study revealed α-bisabolol has a good binding energy of - 7.11 kcal/mol with 14-α-demethylase enzyme, which is crucial for ergosterol synthesis. Therefore, the cell membrane integrity may be affected by treatment with α-bisabolol. qRT-PCR studies proved that α-bisabolol treatment affects gene expression in C. albicans. In silico binding affinity was also analyzed for RAS1, TUP1 and CST20 in the signal transduction pathway and exhibited binding affinities for at - 7.7 kcal/mol, - 8.21 kcal/mol, and for - 5.79 kcal/mol respectively. In conclusion, α-bisabolol caused reduced biofilm, ergosterol synthesis along with altered gene expressions in C. albicans with no hemolysis. This study proposed α-bisabolol as an alternative antifungal agent.

RevDate: 2025-04-05

Wang G, Zhang H, Wu Q, et al (2025)

Study on the invitro synergistic susceptibility and biofilm inhibition mechanism of ceftazidime-avibactam combined with aztreonam against carbapenem-resistant Klebsiella pneumoniae.

Frontiers in microbiology, 16:1542029.

OBJECTIVE: This study aims to investigate the synergistic effects and biofilm inhibition mechanisms of ceftazidime-avibactam (CZA) combined with aztreonam (ATM) against carbapenem-resistant Klebsiella pneumonia (CRKP) commonly found in the local clinical setting, providing new insights for clinical anti-infective strategies.

METHODS: We selected a total of 150 non-duplicate clinical isolates of CRKP from multiple hospitals in Ningbo. Common carbapenemase genes were detected using PCR. Broth microdilution and time-kill assays were used to evaluate the in vitro synergistic effects of CZA and ATM, both individually and in combination, on CRKP isolates with different enzyme types, and the fractional inhibitory concentration index (FICI) was calculated. The crystal violet staining method and bacterial cell permeability assay were employed to assess the impact of CZA, ATM, and their combination on the cell structure and biofilm formation capacity of CRKP. Real-time quantitative PCR (qRT-PCR) was used to measure the expression levels of biofilm-related genes (Luxs, mrkA, wbbM, pgaA, and wzm) in CRKP under treatment with CZA, ATM, or their combination.

RESULTS: The comparison of synergistic indices for different enzyme-type CRKP strains with CZA and ATM combination therapy showed a statistically significant difference (p < 0.01). The time-kill assay indicated that the time-kill curves for strains carrying blaKPC-2 and blaNDM-1 resistance genes were similar between the monotherapy and combination therapy groups, while the CZA + ATM combination therapy group showed a significant decrease in bacterial concentration after 4-8 h of cultivation compared to the CZA and ATM monotherapy groups. The crystal violet staining and bacterial cell permeability assays demonstrated that the CZA + ATM combination significantly reduced biofilm formation and increased cellular structure disruption in CRKP. The qRT-PCR results showed that CZA combined with ATM notably decreased the expression levels of biofilm-related genes Luxs, mrkA, wbbM, pgaA, and wzm in CRKP.

CONCLUSION: The combination of ATM and CZA shows a strong synergistic antibacterial effect against CRKP strains with various enzyme types, with particularly notable synergy in strains carrying the blaKPC-2 resistance gene. Additionally, this combination significantly disrupts the cellular structure of CRKP and inhibits biofilm formation.

RevDate: 2025-04-05

Patra S, Pradhan B, A Roychowdhury (2025)

Complete genome sequence, metabolic profiling and functional studies reveal Ligilactobacillus salivarius LS-ARS2 is a promising biofilm-forming probiotic with significant antioxidant, antibacterial, and antibiofilm potential.

Frontiers in microbiology, 16:1535388.

BACKGROUND: Probiotics restore microbial balance and prevent gut-inflammation. Therefore, finding out novel probiotic strains is a demand. As gut-microbe, benefits of Ligilactobacillus salivarius (LS) are established. However, strain-specific detailed studies are limited. Here, we illustrate probiotic attributes of novel LS-ARS2 for its potential application as food-supplement and/or therapeutic to improve gut-health.

METHODS: Whole genome sequencing (WGS) and phylogenetic analysis confirm the strain as LS. To establish probiotic properties, acid-bile tolerance, auto-aggregation, cell-surface-hydrophobicity, biofilm-formation, and adhesion-assays are performed. To ensure safety attributes, antibiotic-susceptibility, hemolytic, DNase, trypan-blue, and MTT assays are done. ABTS, DPPH, superoxide, hydroxyl free radical scavenging assays are used to determine anti-oxidant potential. Antibacterial assays, including co-culture assay with pathogen and pathogenic biofilm-inhibition assays, are performed to explore antibacterial efficacy. To characterize metabolic-profile of LS-ARS2-derived cell-free-supernatant (CFS), HRMS analysis are carried out. Consequently, WGS-analyses predict potential molecular associations related to functional outcomes.

RESULTS: We find LS-ARS2 a remarkable fast-growing strain that shows acid and bile tolerance (>60% survival rate), indicating promising gut-sustainability. High auto-aggregation capacity (>80%), robust cell-surface hydrophobicity (>85%), and adhesion efficacy to Caco-2 cells illustrate significant potential of LS-ARS2 for gut colonization. Fascinatingly, LS-ARS2 is able to form biofilm within 24 h (p < 0.0001), rare among LS strains, indicating the potential of the strain for efficient stay in the gut. The strain ensures safety attributes. LS-ARS2-WGS analysis recognizes probiotic-specific determinants, predicts genomic stability, identifies orthologous-clusters for diverse functions, and predicts metabolites and bacteriocins. HRMS-studies with LS-ARS2-CFS further validate the presence of diverse beneficial metabolites with antimicrobial and immunomodulatory potential. LS-ARS2 shows significant antioxidant properties in ABTS (>60%), DPPH (>10 U/mL), superoxide (>70%), and hydroxyl free radical scavenging assays (>70%). Further, LS-ARS2 shows antimicrobial activities against Gram-positive Methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative multidrug-resistant clinical strains enterotoxigenic Escherichia coli, Vibrio cholerae, and Shigella flexneri. Anti-Salmonella effect of LS-ARS2 is prominent (p < 0.0001). Most interestingly, LS-ARS2-CFS inhibits MRSA-biofilm (p < 0.0001), again rare among LS strains.

CONCLUSION: LS-ARS2 is a novel, fast-growing, biofilm-forming probiotic with significant antioxidant, antibacterial, and anti-biofilm potentials, suggesting the promising applications of LS-ARS2 for combating pathogenic biofilms and improving gut-health. However, further in vivo studies would facilitate their potential applications.

RevDate: 2025-04-05

Sun Y, Wu Y, Chang Y, et al (2025)

Exploring the antibacterial and anti-biofilm properties of Diacerein against methicillin-resistant Staphylococcus aureus.

Frontiers in microbiology, 16:1545902.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant clinical challenge due to its multidrug resistance. Diacerein (DIA), primarily used to treat degenerative joint diseases, has recently been found to exhibit antibacterial activity, though its specific antibacterial mechanisms remain unclear.

METHODS: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of DIA, as well as in - vitro combination susceptibility testing, were determined using the broth microdilution method. Additionally, resistance induction assays, time-growth curve measurements, membrane fluidity, intracellular protein levels, and reactive oxygen species (ROS) were assessed. The inhibition and clearance of MRSA biofilms by DIA were evaluated using the crystal violet staining method, with bacterial morphology and biofilms observed via scanning electron microscopy and confocal laser scanning microscopy. Finally, transcriptome analysis was conducted to identify gene expression changes in MRSA treated with DIA, and RT-qPCR verification was performed.

RESULTS: The MIC and MBC of DIA against MRSA were 32 μg/mL and 128 μg/mL, respectively, and synergistic antibacterial effects when combined with ampicillin. DIA increased intracellular ROS levels and membrane fluidity in MRSA, decreased soluble protein synthesis, and altered bacterial morphology. Additionally, DIA significantly inhibited MRSA biofilm formation and disrupted pre - existing biofilms. Transcriptome analysis revealed 1,045 differentially expressed genes between the DIA-treated group and the control group, primarily involving pathways such as the tricarboxylic acid cycle, phosphorylation, ribosome metabolism, and nucleotide metabolism.

CONCLUSION: In summary, DIA has antibacterial and anti-biofilm activities against MRSA and does not easily induce resistance. Its antibacterial mechanisms may involve multiple aspects, including bacterial protein synthesis, energy metabolism.

RevDate: 2025-04-05

Pitton M, Valente LG, Oberhaensli S, et al (2025)

Targeting Chronic Biofilm Infections With Patient-derived Phages: An In Vitro and Ex Vivo Proof-of-concept Study in Patients With Left Ventricular Assist Devices.

Open forum infectious diseases, 12(4):ofaf158.

BACKGROUND: Phage therapy is being reconsidered as a valuable approach to combat antimicrobial resistance. We recently established a personalized phage therapy pipeline in healthy volunteers, where therapeutic phages were isolated from individuals' skin microbiota. In this study, we aim to validate this pipeline in end-stage heart failure patients supported by left ventricular assist devices (LVADs), focusing on phages targeting Staphylococcus epidermidis, a common pathogen responsible for LVAD infections.

METHODS: Over a 2.5-year period, 45 LVAD patients were consistently sampled at their driveline exit sites and foreheads. S epidermidis strains from patients' foreheads were used to amplify patient-specific phages. Newly isolated phages were characterized and tested against S epidermidis isolates (n = 42) from the patient cohort. The virulent phage vB_SepS_BE22, isolated from a patient with a driveline infection, was further tested for its bactericidal activity against S epidermidis biofilms ex vivo with rifampicin on driveline biofilms.

RESULTS: S epidermidis was detected in 32 patients, 3 of whom had driveline infections. Phages were isolated from 8 patients, 6 of which were unique and exhibited narrow host ranges, infecting 19%-52% of S epidermidis strains. vB_SepS_BE22, isolated from patient ID25's microbiota, was the only phage that specifically killed S epidermidis clones linked to a patient's infection. vB_SepS_BE22 also reduced bacterial loads in exponential and stationary phase cultures, as well as in biofilms on drivelines when combined with rifampicin.

CONCLUSIONS: This study validated a personalized phage therapy approach, where phages from a patient's own microbiota can be used in chronic infection settings as therapeutic agents.

RevDate: 2025-04-05
CmpDate: 2025-04-03

Schubert A, Friebel JM, Bunz O, et al (2025)

Aggregatibacter actinomycetemcomitans induces biofilm formation of Streptococcus sanguinis on titanium implants.

International journal of implant dentistry, 11(1):29.

PURPOSE: This study aims to investigate the distinct behaviors of single-species and dual-species biofilms formed by Streptococcus sanguinis and Aggregatibacter actinomycetemcomitans on different titanium and implant surfaces. Four types of surfaces were examined: two clinically used implant surfaces, a super-polished surface and a sand-blasted surface of grade 4 titanium.

METHODS: Specimens were incubated with single- and dual-species biofilms for 24 h. Biofilm formation was determined based on the amount of total DNA extracted from the bacteria. In order to specifically determine the biofilm formation of Streptococcus sanguinis, qPCR experiments were carried out. Staining followed by fluorescence microscopy was employed to verify the efficiency of the washing steps.

RESULTS: Biofilm formation by single- and dual-species cultures was observed on all tested implant surfaces. However, a clear influence of surface characteristics on biofilm formation could not be conclusively demonstrated. Mixed cultures of S. sanguinis and A. actinomycetemcomitans (AAC) exhibited increased biofilm formation through the enhanced DNA amount of S. sanguinis. In contrast, this effect was not observed in dual-species cultures of Staphylococcus epidermidis and S. sanguinis.

CONCLUSION: AAC promotes biofilm formation of S. sanguinis, highlighting the significant role of AAC in enhancing biofilm development. Conversely, a definitive conclusion regarding the correlation between titanium implant surface roughness and biofilm formation was not possible. However, our results suggest a tendency that dual-species biofilm formation may be influenced by surface structure.

RevDate: 2025-04-03

Iszatt JJ, Larcombe AN, Garratt LW, et al (2025)

Lytic activity, stability, biofilm disruption capabilities and genomic characterisation of two bacteriophages active against respiratory MRSA.

Journal of applied microbiology pii:8105717 [Epub ahead of print].

AIMS: This study aimed to characterise bacteriophages for potential therapeutic use against Staphylococcus aureus, focusing on clinical respiratory isolates of methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains. Specifically, it sought to evaluate phage lytic activity, host range, stability, biofilm disruption capabilities, and overall safety for therapeutic use.

METHODS AND RESULTS: Novel phages, Koomba kaat 1 and Biyabeda mokiny 1, were identified and characterised using microbiological assays and bioinformatics. They exhibited lytic activity against clinical MSSA and MRSA isolates, disrupted biofilms from airway isolates, remained stable for at least one year in storage, and could be aerosolized without significant reductions in activity. Bioinformatic tools were used to assess safety, lifecycle, virulence, and prophage contamination when grown using their original isolation host. Receptor binding proteins within their genomes were also predicted, providing insight into their mechanisms of action. Both phages demonstrated strong efficacy against the clinical isolates tested and demonstrated robust stability under storage and delivery conditions.

CONCLUSIONS: Koomba kaat 1 and Biyabeda mokiny 1 are promising candidates for phage therapy. Their efficacy against clinical S. aureus isolates, ability to break down biofilm, and stability for airway implementation, positions them as valuable tools for addressing persistent airway infections caused by S. aureus.

RevDate: 2025-04-03

Karasu O, Ayhan MS, Duran M, et al (2025)

A Novel Approach for Preventing Biofilm Formation on Various Breast Implant Surfaces: Bacteriophage Therapy.

Plastic and reconstructive surgery pii:00006534-990000000-02603 [Epub ahead of print].

BACKGROUND: Capsular contracture is a common complication in breast implant surgery, with subclinical bacterial inflammation being a significant factor. Traditional methods to prevent capsular contracture include antibiotic irrigation and systemic antibiotics. However, the rise of antibiotic-resistant bacteria has driven the need for alternative treatments. Bacteriophages, capable of lysing bacteria and preventing biofilm formation, are emerging as a potential alternative. This study aims to compare the efficacy of local bacteriophage therapy and local antibiotic treatment in preventing biofilm formation on breast implants.

MATERIAL AND METHODS: Fifty-four Wistar Albino rats were divided into three groups: control, antibiotic, and bacteriophage, each with three subgroups for different time points (6 hours, 24 hours, and 30 days). Three types of implant surfaces (smooth, textured, and polyurethane) were incubated with a biofilm-producing strain of Staphylococcus epidermidis before implantation. The implant surfaces in the experimental groups were treated with either antibiotic or bacteriophage solutions before implantation. Samples were collected at 6 hours, 24 hours, and 30 days post-implantation for colony counting and mRNA analysis of the sesI gene.

RESULTS: Both bacteriophage and antibiotic treatments significantly reduced colony counts, and mRNA expression compared to the control group at all time points (p<0.05). No significant difference was found between the antibiotic and bacteriophage groups. Textured and polyurethane implants showed lower bacterial loads in the experimental groups compared to smooth implants.

CONCLUSION: This study highlights bacteriophages as a promising alternative to antibiotics for preventing biofilm formation on breast implants, representing a pioneering effort in demonstrating their potential.

RevDate: 2025-04-03

Ravishankar S, Conte AL, Carrasco Aliaga SJ, et al (2025)

The antimycotic 5-fluorocytosine is a virulence inhibitor of uropathogenic Escherichia coli and eradicates biofilm-embedded bacteria synergizing with β-lactams.

Antimicrobial agents and chemotherapy [Epub ahead of print].

Biofilm can enhance antibiotic tolerance in bacteria, making treatment of biofilm-associated infections in clinical settings a significant challenge. 5-Fluorocytosine (5-FC), an FDA-approved drug mostly used as an antifungal, can hinder biofilm formation and production of virulence factors in Gram-negative bacteria. In this study, we tested 5-FC on nine uropathogenic Escherichia coli (UPEC) strains plus a fecal isolate. Our data indicated that 5-FC reduced curli fiber gene expression and inhibited virulence factors in UPEC strains. Unlike what was observed in other microorganisms, 5-FC antivirulence and antibiofilm properties were unaffected by either growth temperature or the medium pH, which might prove critical in urinary tract infection (UTI) treatment. Additionally, 5-FC impaired the expression of various UPEC virulence factors, including secreted toxins and type I and P fimbriae, thus leading to decreased UPEC adherence to bladder epithelial cells and improved survival of host cells. Finally, we found that a combination of 5-FC with β-lactams, but not other classes of antibiotics, significantly lowered the viability of bacteria in preformed biofilms. Despite a small set of pathogenic E. coli strains and an in vitro infection model, our findings strongly suggest that 5-FC might be a possible candidate as an antivirulence agent, particularly in a synergistic approach with β-lactam antibiotics.

RevDate: 2025-04-02

Long M, Zheng CW, Zhou C, et al (2025)

Mitigating chromate toxicity through concurrent denitrification in the H2-based membrane biofilm reactor.

Journal of hazardous materials, 492:138073 pii:S0304-3894(25)00988-4 [Epub ahead of print].

High concentrations of hexavalent chromium (Cr(VI)) in industrial wastewaters pose significant environmental and health hazards. Biotranformation is a viable means to lower Cr(VI) toxicity, but research to date has focused on wastewaters with low concentrations (e.g., 2-5 mg/L Cr(VI)). This study evaluated the dynamics of biosorption and biotransformation of higher-concentration Cr(VI) by biofilms in the H2-based membrane biofilm reactor (MBfR). While the biofilm in an MBfR receiving Cr(VI) alone had limited capacity to remove Cr(VI) and Cr(VI) removal ceased in 30 days, an autotrophic denitrifying biofilms achieved 99 % reduction of over 20 mg/L Cr(VI) to less-toxic trivalent chromium (Cr(III)) in continuous long-term operation system over 4 months. Increasing the H2 pressure from 3 psig to 10 psig improved Cr(VI) removal from 87 % to 99 %, which occurred in parallel with over 95 % NO3[-] reduction to N2. Metagenomic analyses revealed the mechanisms of Cr(VI) bioreduction and highlighted the beneficial role of nitrate (NO3[-]) as the primary electron acceptor. For example, nitrite reductase NrfA could reduce Cr(VI), which lowered Cr(VI) caused oxidative stress. This research demonstrates the MBfR's effectiveness in reducing elevated levels of Cr(VI) and provides mechanistic understanding of the roles of denitrification in accelerating Cr(VI) reduction and detoxification.

RevDate: 2025-04-02

Sandeep R, Madsen JS, Marzocchi U, et al (2025)

Synergizing carbon and phosphorus recovery from wastewater: Integrating biofilm-based phosphorus removal in high-rate activated sludge.

Water research, 280:123546 pii:S0043-1354(25)00459-2 [Epub ahead of print].

High-rate activated sludge operated at <2 days biomass age enhances carbon recovery from wastewater, but simultaneous biological recovery of phosphorus remains unachieved. Addressing the reported loss of phosphorus accumulating organisms (PAO) at such short biomass ages, this study investigated the integration of moving bed biofilms into high-rate activated sludge to enhance PAO retention. The results demonstrated sustained biofilm-based PAO activity and complete orthoP removal under short anaerobic-aerobic cycles with a hydraulic retention time of 2.7 h matching high-rate conditions. When combined with high-rate activated sludge in a sequencing batch reactor fed with acetate, complete orthoP removal was sustained. However, using synthetic wastewater promoted the growth of competing heterotrophic bacteria, reducing orthoP removal to 50-65 %. Biofilms served as a continuous source of PAO for the suspended biomass, which contributed to 46-55 % of the overall orthoP removal, even below 2 days biomass age. While acetate-fed microbial communities included known PAOs, using complex feed shifted the community toward less understood putative PAOs. Competition for acetate was likely compensated by a high fermentability of high-rate activated sludge, as PAO activity was maintained while reducing the acetate load in the feed from 20:1 to 5:1 g acetate⋅g P[-1]. P release and uptake rates were accurately described by the biomass-specific acetate loading rate and the depletion of intracellular polyphosphate, respectively, providing predictive relationships for process optimization. Imposing an anaerobic-aerobic regime enhanced the carbon recovery of high-rate activated sludge from about 37 to 60 %. Integrating biofilms enabled efficient phosphorus removal while maintaining carbon recovery rates of 41-53 %, highlighting the synergistic benefits of this approach.

RevDate: 2025-04-02

Lee S, Tsavou A, Zarnowski R, et al (2025)

Candida albicans biofilm extracellular vesicles deliver candidalysin to epithelial cell membranes and induce host cell responses.

Infection and immunity [Epub ahead of print].

Extracellular vesicles (EVs) are heterogeneous particles encapsulated with a phospholipid bilayer membrane. EVs have evolved diverse biological functions, serving mainly as prominent mediators and regulators of cell-cell communication. This study investigated whether candidalysin, a key virulence factor in Candida albicans infections, is present within EVs derived from C. albicans biofilms and retains activity by inducing host immune responses. We found that biofilm EVs contain candidalysin and can permeabilize planar lipid bilayer membranes in a dose-dependent manner. However, biofilm EVs were unable to damage oral epithelial cells (OECs) but were able to induce cytokine responses. Notably, EVs obtained from biofilms cultured for 24 h and 48 h exhibited differences in cargo composition and their ability to activate OECs. This study highlights the potential of biofilm EVs as a toxin delivery system during C. albicans infection and identifies temporal differences in the ability of EVs to activate epithelial cells.

RevDate: 2025-04-03
CmpDate: 2025-04-02

Flumignan VK, Sircili MP, Franzolin MR, et al (2025)

Comparison between biliary plastic stents with and without application of silver nanoparticles: an in-vitro study of the biofilm formation.

Acta cirurgica brasileira, 40:e402825.

PURPOSE: Plastic biliary stents are a cost-effective treatment for biliary obstruction. Unfortunately, they have low patency, related to intraluminal biofilm formation. Silver nanoparticles (AgNPs) have been increasingly used in biomedicine because of its antibacterial properties. This study aimed to compare biofilm formation on stents with and without silver nanoparticle coatings when in contact with different bacterial culture medium.

METHODS: Different types of silver coatings were tested on plastic biliary stents. Two groups of stents were analyzed: one group with various types of silver nanoparticle coatings, and a negative control group with no coating. The stents were placed in different bacterial culture media and assessed for biofilm formation. Analysis was performed using confocal microscopy and direct colony-forming unit (CFU/cm2).

RESULTS: Quantitative analysis showed promising results with C16 coating, as Escherichia coli ATCC and Pseudomonas aeruginosa ATCC exhibited reduced growth in the AgNP-coated group (p < 0.05). However, when mixed samples, including clinical strains and Staphylococcus aureus, were tested, the AgNP coating did not inhibit bacterial growth.

CONCLUSION: AgNP-coated stents are effective against certain strains, such as E. coli ATCC and P. aeruginosa. Further research is needed to explore potential improvements in the coating mechanism.

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

Wang L, Wang J, Zhang K, et al (2025)

Linalool as a potential agent for inhibiting Escherichia coli biofilm formation and exopolysaccharide production.

BMC veterinary research, 21(1):235.

Escherichia coli (E. coli) is one of the most common pathogens causing endometritis in dairy cows. The presence of genes encoding extended-spectrum β-lactamase (ESBL) and biofilm formation are important factors contributing to bacterial resistance, which poses a significant challenge to the treatment of endometritis in dairy cows. Essential oils containing linalool have been shown to improve the cure rate of bovine endometritis, but whether linalool can inhibit E. coli biofilm has not yet been reported. We proposed to ascertain the linalool implications on the development of E. coli biofilm and its extracellular polysaccharides, as well as to assess the impacts of linalool on E. coli in both planktonic and biofilm states. We discovered that the minimum biofilm inhibitory concentrations (MBICs) of linalool against E. coli were twice as high as the minimum inhibitory concentrations. Linalool exhibited a strong bactericidal effect on clinical E. coli strain producing ESBL and forming strong biofilm, regardless of whether they were in a planktonic or biofilm condition. Linalool suppressed the biofilm development in a way that was dependent on the dosage, with an MBIC 4 µL/mL. This was verified by the use of crystal violet test and scanning electron microscopy. Moreover, the CCK-8 assay and confocal laser scanning microscopy (CLSM) manifested significant reductions in live bacteria within the biofilm. The concentrations of extracellular polymeric compounds in the E. coli biofilm were also reduced. Furthermore, CLSM and RT-qPCR analysis confirmed that linalool (2 µL/mL) significantly suppressed exopolysaccharide (EPS) and the pgaABCD gene expression, regulating an essential exopolysaccharide expression in biofilm formation. These findings revealed that linalool effectively suppressed viable bacteria, EPS production, and E. coli biofilm formation, providing a theoretical foundation for alternative antibiotic therapy in endometritis in dairy cows and as a potential agent for preventing E. coli biofilm-related infections.

RevDate: 2025-04-04

Choi V, Carugo D, E Stride (2025)

Repurposing antimicrobials with ultrasound-triggered nanoscale systems for targeted biofilm drug delivery.

npj antimicrobials and resistance, 3(1):22.

Chronic infections represent a major clinical challenge due to the enhanced antimicrobial tolerance of biofilm-dwelling bacteria. To address this challenge, an ultrasound-responsive nanoscale drug delivery platform (nanodroplets) is presented in this work, loaded with four different antimicrobial agents, capable of simultaneous biofilm disruption and targeted antimicrobial delivery. When loaded, a robust protective effect against clinically-derived MRSA and ESBL Gram-positive and Gram-negative planktonic isolates was shown in vitro. Upon application of therapeutic ultrasound, an average 7.6-fold, 44.4-fold, and 25.5-fold reduction was observed in the antibiotic concentrations compared to free drug required to reach the MBC, MBEC and complete persister eradication levels, respectively. Nanodroplets substantially altered subcellular distribution of encapsulated antimicrobials, enhancing accumulation of antimicrobials by 11.1-fold within the biofilm-residing bacteria's cytoplasm compared to treatment with unencapsulated drugs. These findings illustrate the potential of this multifunctional platform to overcome the critical penetration and localization limitations of antimicrobials within biofilms, opening potential new avenues in the treatment of chronic clinical infections.

RevDate: 2025-04-02

Sun J, Shen HL, Pan JN, et al (2025)

Ferrous sulfate/carboxymethyl chitosan agar-based film triggers ferroptosis in Pseudomonas aeruginosa planktonic and biofilm cells for antibacterial preservation of fruits and vegetables.

International journal of biological macromolecules, 308(Pt 3):142697 pii:S0141-8130(25)03249-0 [Epub ahead of print].

The ferrous sulfate (FeSO4)-based mechanism causing ferroptosis-like death in Pseudomonas aeruginosa was investigated. FeSO4 triggered ferroptosis in P. aeruginosa planktonic cells, decreased the ratio of glutathione to oxidized glutathione, and resulted in the increase of reactive oxygen species and lipid peroxidation, damaging the integrity of the cell membrane. In addition, FeSO4 prevented P. aeruginosa from forming biofilms on the surface of stainless steel, glass, and high-density polyethylene. Transcriptome analyses indicated that there were 412 up-regulated genes and 782 down-regulated genes following FeSO4 treatment. FeSO4 increased the cross-linking density of a carboxymethyl chitosan (CMCS) agar-based film, reducing its water solubility, swelling degree, water vapor permeability, and oxygen permeability. Finally, FeSO4@CMCS agar-based film showed potential antibacterial ability against the growth of P. aeruginosa in grapes, purple kale, and cherry tomatoes during storage.

RevDate: 2025-04-01

Chen L, Shi H, Medema G, et al (2025)

Long-term impacts of free chlorine and monochloramine on the development of drinking water biofilm.

Water research, 281:123566 pii:S0043-1354(25)00479-8 [Epub ahead of print].

Biofilm formation in drinking water distribution systems is primarily managed by disinfectants such as free chlorine (FC) and monochloramine (MC). However, there is limited understanding of their long-term and dynamic effects on biofilm development. To address this, a 56-week study was conducted to comprehensively assess biofilm development in terms of microbial quantity and community under different disinfection regimes: no chlorine (NC), FC (0.1 mg/L), and MC (0.4 mg/L). The results showed that both FC and MC significantly inhibited biofilm growth compared to the NC condition while shaping distinct biofilm communities. Notably, FC drastically reduced biofilm biomass and community diversity, resulting in a more uniform biofilm community predominantly composed of Proteobacteria (e.g., Rhizobacter spp., Pseudomonas spp., and Hyphomicrobium spp.), indicating stronger selection pressures on the microbial population. In contrast, though MC effectively reduced the biofilm biomass to a level comparable to that of FC, it maintained a high diversity comparable to that of NC (dominated by Sphingobium spp. and Nocardioides spp.), reflecting weaker selection pressure on bacterial community. Temporally, biofilm communities under all conditions started from nearly identical states. From week-19 and week-36 onwards, deterministic processes predominantly governed biofilm formation under FC and NC conditions, signifying that these biofilms reached a stable state. Differently, under MC condition, the community assembly was continually influenced by stochastic processes, with the biofilm not achieving stability until week-56. Overall, this study provides valuable insights into the long-term dynamics of biofilm development and evidenced that FC is better than MC in controlling biofilm formation, particularly from the community diversity perspective. This challenges classical views that MC is more effective than FC in penetrating and controlling biofilm, which may change the popularity of MC as a disinfectant in water utilities.

RevDate: 2025-04-01

Shah T, Zhu C, Shah C, et al (2025)

Trans-cinnamaldehyde nanoemulsion reduces Salmonella Enteritidis biofilm on steel and plastic surfaces and downregulates expression of biofilm associated genes.

Poultry science, 104(5):105086 pii:S0032-5791(25)00325-6 [Epub ahead of print].

Salmonella Enteritidis is a major poultry-associated foodborne pathogen that can form sanitizer-tolerant biofilms on various surfaces. The biofilm-forming capability of S. Enteritidis facilitates its survival on farm and food processing equipment. Conventional sanitization methods are not completely effective in killing S. Enteritidis biofilms. This study investigated the efficacy of a Generally Recognized as Safe phytochemical Trans-cinnamaldehyde (TC), and in its nanoemulsion form (TCNE), for inhibiting S. Enteritidis biofilm formation and inactivating mature biofilms developed on polystyrene and stainless-steel surfaces. Moreover, the effect of TC on Salmonella genes critical for biofilm formation was studied. TCNE was prepared using a high energy sonication method with Tween 80. For biofilm inhibition assay, S. Enteritidis was allowed to form biofilms either in the presence or absence of sub-inhibitory concentration (SIC; 0.01 %) of TCNE at 25°C and the biofilm formed was quantified at 24-h intervals for 48 h. For the inactivation assay, S. Enteritidis biofilms developed at 25°C for 48 h were exposed to TCNE (0.5, 1 %) for 1, 5, and 15 min, and surviving S. Enteritidis in the biofilm were enumerated. SIC of TCNE inhibited S. Enteritidis biofilm by 45 % on polystyrene and 75 % on steel surface after 48 h at 25°C compared to control (P < 0.05). All TCNE treatments rapidly inactivated S. Enteritidis mature biofilm on polystyrene and steel surfaces (P < 0.05). The lower concentration of TCNE (0.5 %) reduced S. Enteritidis counts by 1.5 log CFU/ml as early as 1 min of exposure on both polystyrene and stainless-steel surfaces. After 15 min of exposure, TCNE at concentration of 0.5 or 1 % reduced S. Enteritidis count significantly by 4.5 log CFU or 6 log CFU/ml on polystyrene or stainless-steel surfaces. TC downregulated the expression of S. Enteritidis genes (hilA, hilC, flhD, csgA, csgD, sdiA) responsible for biofilm formation (P < 0.05). Results suggest that TCNE has potential as a natural disinfectant for controlling S. Enteritidis biofilms on common farm and food processing surfaces, such as plastic and steel.

RevDate: 2025-04-03
CmpDate: 2025-04-01

He H, Carlson AL, Wagner B, et al (2025)

An update on hybrid membrane aerated biofilm reactor technology.

Water environment research : a research publication of the Water Environment Federation, 97(4):e70065.

The hybrid membrane aerated biofilm reactor (MABR) process combines the advantages of the counter-diffusional biofilm and bubbleless aeration of the MABR with the good bioflocculation and carbon processing capabilities of suspended growth processes. These features result in a process with reduced physical footprint, excellent biological nutrient removal capabilities, potentially reduced greenhouse gas (GHG) emissions, and significantly reduced energy requirements that can be easily retrofitted into existing suspended growth processes. Commercially introduced in the mid-2010s, the demonstrated advantages of the hybrid MABR process are resulting in rapid full-scale adoption. Meanwhile, researchers are advancing knowledge on the hybrid MABR process and revealing potential opportunities for improved performance. This paper summarizes recent findings and identifies areas that can be further developed to advance hybrid MABR process evaluation and development. PRACTITIONER POINTS: Rapid application of the hybrid MABR process is leading to significant new developments that can enhance performance. Sizing MABR for nearly complete nitrification allows significant downsizing of the bioreactor, coupled with excellent nitrogen removal and energy savings. Online exhaust gas % O2 and bulk ammonia concentration can be used to create a soft sensor characterizing changes in biofilm thickness enabling biofilm control to optimize performance. Further advancements through improved aeration control, configurations to achieve partial nitritation and annammox, and achieving granulation offer further significant advances.

RevDate: 2025-04-01
CmpDate: 2025-04-01

Horsnell A, Farella M, Tompkins G, et al (2025)

Comparison of Biofilm Accumulation on Conventional and CAD/CAM Orthodontic Band Alloys (In Vivo) and Subsequent Enamel Demineralization (Ex Vivo).

Journal of biomedical materials research. Part B, Applied biomaterials, 113(4):e35573.

Biofilm accumulation can lead to enamel decalcification, gingivitis, and periodontal disease. The objective of this study was to compare the accumulation of biofilm under in vivo conditions and consequent ex vivo acid production and enamel demineralization around the material used for "off-the-shelf" conventional and CAD/CAM orthodontics bands. The study design required both in vivo and in vitro approaches. An experimental model was utilized to combine the exposure of an in vivo formed biofilm to in vitro cariogenic conditions to achieve the objective. Twenty-one consenting participants took part in this study. Participants wore custom intraoral appliances containing six bovine enamel discs (three on each maxillary arch) for 48 h. Tiles made from conventional stainless steel bands (SS tiles group), CAD/CAM tiles made of Sintron cobalt-chromium (CoCr) sinter metal (Sintron tiles group), and no tile (control group) were randomly assigned to disc positions such that each appliance contained two tiles from each group (126 tiles in total). Participants immersed the appliances in sucrose solution (10% w/v) for 5 min, five times per day. After 48 h, appliances were removed, the discs were recovered, and incubated in glucose (1%)/PBS for 24 h. The pH of the glucose/PBS measured the relative acid produced by the accumulated biofilm, and calcium released from the discs quantified demineralization. Disclosing dye was used to stain and delineate the biofilm before each disc was digitally photographed and analyzed to determine the biofilm coverage. The mean biofilm coverage ranged between 0% and 86% (mean 9.63%) of disc surface area, but there was no difference in biofilm coverage between tile groups or between tile positions. Significantly less acid was generated by the control discs biofilms (mean pH 5.06) than either SS or CAD/CAM tiles biofilms (pH 4.72 and 4.84, respectively), which were not different from one another. Position on the appliance did not affect acid production. Control discs experienced greater demineralization (mean 136 μg Ca/disc) than either the SS (122 μg Ca/disc) or Sintron (114 μg Ca/disc) tile groups, which suffered equivalent demineralization. Position on the appliances did not influence demineralization. The study provides no evidence that CAD/CAM-designed components of orthodontic bands are more beneficial than conventional bands in terms of biofilm accumulation and consequent caries risk.

RevDate: 2025-04-01

Lormand JD, Savelle CH, Teschler JK, et al (2025)

A class of secreted retropepsin-like enzymes is required for osmotic stress tolerance, antibiotic resistance and biofilm formation in Pseudomonas aeruginosa.

bioRxiv : the preprint server for biology pii:2025.03.18.643919.

UNLABELLED: Proteases regulate important biological functions. Here we present the structural and functional characterization of three previously uncharacterized aspartic proteases in Pseudomonas aeruginosa . We show that these proteases have structural hallmarks of retropepsin peptidases and play redundant roles for cell survival under hypoosmotic stress conditions. Consequently, we named them retropepsin-like osmotic stress tolerance peptidases (Rlo). Our research shows that while Rlo proteases are homologous to RimB, an aspartic peptidase involved in rhizosphere colonization and plant infection, they contain N-terminal signal peptides and perform distinct biological functions. Mutants lacking all three secreted Rlo peptidases show defects in antibiotic resistance, biofilm formation, and cell morphology. These defects are rescued by mutations in the inactive transglutaminase transmembrane protein RloB and the cytoplasmic ATP-grasp protein RloC, two previously uncharacterized genes in the same operon as one of the Rlo proteases. These studies identify Rlo proteases and rlo operon products as critical factors in clinically relevant processes, making them appealing targets for therapeutic strategies against Pseudomonas infections.

IMPORTANCE: Bacterial infections have become harder to treat due to the ability of pathogens to adapt to different environments and the rise of antimicrobial resistance. This has led to longer illnesses, increased medical costs, and higher mortality rates. The opportunistic pathogen Pseudomonas aeruginosa is particularly problematic because of its inherent resistance to many antibiotics and its capacity to form biofilms, structures that allow bacteria to withstand hostile conditions. Our study uncovers a new class of retropepsin-like proteases in P. aeruginosa that are required for biofilm formation and bacterial survival upon stress conditions, including antibiotic exposure. By identifying critical factors that determine bacterial fitness and adaptability, our research lays the foundation for developing new therapeutic strategies against bacterial infections.

RevDate: 2025-04-02

Catania AM, Dalmasso A, Morra P, et al (2025)

Effect of gaseous ozone treatment on cells and biofilm of dairy Bacillus spp. isolates.

Frontiers in microbiology, 16:1538456.

Bacillus spp. can produce biofilms and cause recurrent contamination in the food industry. The common clean-in-place (CIP) method is usually employed in sanitizing processing equipment. However, CIP is not always effective in removing biofilms. Ozone represents a promising "green" alternative to control biofilms. In this study, the effect of gaseous ozone (50 ppm) was evaluated in vitro against planktonic and sessile B. cereus and B. subtilis isolates collected from the dairy sector. Planktonic cells were enumerated by plate counts after 10 min, 1 h, and 6 h of ozone treatment. After a short-term (10 min) exposure, a slight reduction in microbial loads (0.66-2.27 ± 0.15 Log10 CFU/mL) was observed for B. cereus strains, whereas a more pronounced reduction (2.90-3.81 ± 0.12 Log10 CFU/mL) was noted in B. subtilis isolates. The microbial load further decreased after 1 h-treatments, around 1.5-3.46 ± 0.11 Log10 CFU/mL for B. cereus strains, and 4.0-5.6 ± 0.11 Log10 CFU/mL for B. subtilis isolates, until complete inactivation of bacterial cells after 6 h of exposure. Moreover, the effect of gaseous ozone treatment (50 ppm, 6 h) was evaluated for its ability to inhibit and eradicate biofilms formed on two common food-contact materials (polystyrene and stainless steel). Sessile B. subtilis cells were the more sensitive to the action of ozone, while a weak effect was highlighted on B. cereus isolates on both surface types. These results were further confirmed by scanning microscopy analysis. The number of cells in the biofilm state was also assessed, showing a not-complete correlation with a decrease in Biofilm Production Indices (BPIs). These findings highlighted the effectiveness of the sanitizing protocol using gaseous ozone in contrasting Bacillus free-living cells, but a not completely counteraction in biofilm formation (inhibition) or eradication of pre-formed biofilm. Thus, the application of ozone could be thought of not alone, but in combination with common sanitization practices to improve their effectiveness.

RevDate: 2025-04-02
CmpDate: 2025-04-01

Wannigama DL, Hurst C, Monk PN, et al (2025)

tesG expression as a potential clinical biomarker for chronic Pseudomonas aeruginosa pulmonary biofilm infections.

BMC medicine, 23(1):191.

BACKGROUND: Pseudomonas aeruginosa infections in the lungs affect millions of children and adults worldwide. To our knowledge, no clinically validated prognostic biomarkers for chronic pulmonary P. aeruginosa infections exist. Therefore, this study aims to identify potential prognostic markers for chronic P. aeruginosa biofilm lung infections.

METHODS: Here, we screened the expression of 11 P. aeruginosa regulatory genes (tesG, algD, lasR, lasA, lasB, pelB, phzF, rhlA, rsmY, rsmZ, and sagS) to identify associations between clinical status and chronic biofilm infection.

RESULTS: RNA was extracted from 210 sputum samples from patients (n = 70) with chronic P. aeruginosa lung infections (mean age; 29.3-56.2 years; 33 female). Strong biofilm formation was correlated with prolonged hospital stays (212.2 days vs. 44.4 days) and increased mortality (46.2% (18)). Strong biofilm formation is associated with increased tesG expression (P = 0.001), influencing extended intensive care unit (P = 0.002) or hospitalisation stays (P = 0.001), pneumonia risk (P = 0.006), and mortality (P = 0.001). Notably, tesG expression is linked to the modulation of systemic and sputum inflammatory responses and predicts biofilm biomass.

CONCLUSIONS: This study provides the first clinical dataset of tesG expression levels as a predictive biomarker for chronic P. aeruginosa pulmonary infections.

RevDate: 2025-03-31

Zhou C, Zhu Y, Ren P, et al (2025)

Construction of an efficient enzyme-cell@material biocatalyst through the biofilm immobilization of Komagataella phaffii for continuous biocatalysis.

Bioresource technology pii:S0960-8524(25)00426-2 [Epub ahead of print].

The ever-growing demand for cost-effective and green biocatalytic transformations has prompted the rational design and development of robust biocatalytic tools. However, transformations are hindered by limited continuous process and enzymatic instability. Here, 10 Flo family related genes in Komagataella phaffii were systematically evaluated to assess their adhesive properties. For the first time, we identified the KpFlo11C domain of BSC1p as facilitating cell aggregation on carriers, thereby enhancing the biofilm immobilization process. Furthermore, an engineered K. phaffii strain, fixing β-galactosidase on the cell surface, was constructed by optimizing the signal peptide and gene dosage, for enhancing the efficiency of enzyme targeting and anchoring, as well as the proportion of cells displaying the enzyme. Finally, the KpFlo11C domain was overexpressed in this K. phaffii cell display system to construct the enzyme-cell@material biocatalyst, which exhibited robust continuous production of galacto-oligosaccharides (GOS) at a rate of 8.16 g/L/h in a 6-L fermenter. The development of this enzyme-cell@material biocatalyst, which offers a highly efficient, stable, low-cost, and simplified biocatalytic process, provides a direction for the application of other yeasts in large-scale industrial continuous production.

RevDate: 2025-03-31

Fayed B, El-Sayed HS, Luo S, et al (2025)

Comparative evaluation of biologically and chemically synthesized zinc oxide nanoparticles for preventing Candida auris biofilm.

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

Candidozyma auris (formerly Candida auris) is a multidrug-resistant yeast that poses a significant global health threat due to its ability to form biofilms and resist various antifungal treatments. This study evaluates and compares the antifungal efficacy of biologically synthesized zinc oxide nanoparticles (ZnO-NP-B) and chemically synthesized ZnO nanoparticles (ZnO-NP-C1 and ZnO-NP-C2), developed using the dry-wet chemical method and sol-gel method, respectively. ZnO-NP-B was synthesized using Lactobacillus gasseri. The nanoparticles were characterized for size, charge, and morphology using Particle Size Analyzer, photon correlation spectroscopy with a 90 Plus Zetasizer, and scanning electron microscopy (SEM), respectively. The antifungal activity was assessed through minimum inhibitory concentration (MIC50) determination, biofilm inhibition assays by XTT assay, and gene expression analysis. ZnO-NP-C1 exhibited the highest antifungal activity against C. auris planktonic cells, with a MIC50 value of 61.9 ± 3.3 µg/ml, followed by ZnO-NP-C2 (151 ± 7.83 µg/ml), whereas ZnO-NP-B showed limited efficacy (MIC50 = 1 mg/ml). Chemically synthesized ZnO-NPs, particularly ZnO-NP-C2, did not induce overexpression of resistance genes (CDR1, MDR1, ERG2, ERG11, FKS1, CHS1), whereas ZnO-NP-B triggered their upregulation, potentially promoting resistance. ZnO-NP-C1 was the most effective in preventing biofilm formation, reducing C. auris adhesion by 67.9 ± 2.35% at 150 µg/ml, while ZnO-NP-B exhibited negligible inhibition. Gene expression analysis further confirmed that ZnO-NP-C1 significantly downregulated adhesive genes (ALS5, IFF4, CSA1) by up to 0.37 ± 0.006, 0.043 ± 0.002, and 0.06 ± 0.0004, respectively. These findings highlight the potential of ZnO-NP-C1 as a promising antifungal agent for preventing C. auris biofilms, emphasizing the critical role of synthesis methods in optimizing nanoparticle properties for antifungal applications.

RevDate: 2025-03-31

Vyas HKN, Hoque MM, Xia B, et al (2025)

Transcriptional signatures associated with the survival of Escherichia coli biofilm during treatment with plasma-activated water.

Biofilm, 9:100266.

Biofilm formation on surfaces, tools and equipment can damage their quality and lead to high repair or replacement costs. Plasma-activated water (PAW), a new technology, has shown promise in killing biofilm and non-biofilm bacteria due to reactive oxygen and nitrogen species (RONS), particularly superoxide. However, the exact genetic mechanisms behind PAW's effectiveness against biofilms remain unclear. Here, we examined the stress responses of Escherichia coli biofilms exposed to sub-lethal PAW treatment using bulk RNA sequencing and transcriptomics. We compared gene expression in PAW-treated E. coli biofilms with and without superoxide removal, achieved by adding the scavenger Tiron. Biofilms treated with PAW exhibited a 40 % variation in gene expression compared to those treated with PAW-Tiron and controls. Specifically, PAW treatment resulted in 478 upregulated genes (>1.5 log2FC) and 186 downregulated genes (<-1.5 log2FC) compared to the control. Pathway and biological process enrichment analysis revealed significant upregulation of genes involved in sulfur metabolism, ATP-binding transporter, amino acid metabolism, hypochlorite response systems and oxidative phosphorylation in PAW-treated biofilms compared to control. Biofilm viability and intracellular RONS accumulation were tested for E. coli mutants lacking key genes from these pathways. Knockout mutants of thioredoxin (trxC), thiosulfate-binding proteins (cysP), and NADH dehydrogenase subunit (nuoM) showed significantly reduced biofilm viability after PAW treatment. Notably, ΔtrxC biofilms had the highest intracellular ROS accumulation, as revealed by 2',7'-dichlorofluorescin diacetate staining after PAW treatment. This confirms the importance of these genes in managing oxidative stress caused by PAW and highlights the significance of superoxide in PAW's bactericidal effects. Overall, our findings shed light on the specific genes and pathways that help E. coli biofilms survive and respond to PAW treatment, offering a new understanding of plasma technology and its anti-biofilm mechanisms.

RevDate: 2025-03-31

Lima JC, Ramos LS, Barbosa PF, et al (2025)

Biofilm production by the multidrug-resistant fungus Candida haemulonii is affected by aspartic peptidase inhibitor.

AIMS microbiology, 11(1):228-241.

Candida haemulonii is an emerging, opportunistic, and multidrug-resistant fungal pathogen. Recently, our group reported the ability of C. haemulonii to form biofilm and secrete aspartic-type peptidases (Saps). Herein, we investigated the correlation between Saps production and biofilm formation along C. haemulonii growth in yeast carbon base medium supplemented with albumin (a Sap-inducing condition) and in the presence of the classical Sap inhibitor pepstatin A. Under these conditions, the biofilm biomass increased on a polystyrene surface, reaching its maximum at 96 h, while maximum biofilm viability was detected at 48 h. The release of Saps during biofilm formation showed an inverse trend, with the highest enzymatic activity measured after 24 h. In the presence of pepstatin A, a significant reduction in biofilm parameters (biomass and viability), as well as in albumin consumption by biofilm-forming cells was detected. These findings underscore the importance of Saps during the biofilm development in C. haemulonii.

RevDate: 2025-03-31

Maestri C, Hébert RL, P Di Martino (2025)

Biofilm associated with pigmented areas on a waterproofing coating surface.

AIMS microbiology, 11(1):74-86.

Waterproofing coatings are composite materials made of different layers with complementary functionalities. They may suffer damage that can modify their aesthetic appearance and/or their functionality. In this study, dark stains appearing on a waterproofing coating of a public swimming pool were mapped and characterized at a macroscopic scale through visual observation and by colorimetric analysis, as well as at a microscopic scale with a digital microscope, a confocal laser scanning microscope, and a scanning electron microscope. Five stains were differentiated macroscopically and characterized using colorimetry and principal component analysis. Microscopic observations showed the presence of microorganisms of varied morphology, some filamentous but mostly unicellular. Biofilms consisting of ovoid fluorescent cells with the morphology of Chlorophyta and unicellular cyanobacteria were particularly abundant. The pigmented stains were located at top coat disorders where microbial colonization and biofilm development were observed. The microscopic observations suggested that physical degradation of the surface of the material would have constituted a prerequisite for colonization by pigmented microorganisms which would have led to the development of macroscopically visible pigmented areas. In this case study, the damage remained superficial and did not alter the watertightness of the material so far.

RevDate: 2025-03-31

Branca MT, Silva TP, Lemos ASO, et al (2025)

The Fe-Cyclam-Derived Compound [Fe(cyclam)sal]PF6 Restrains Drug-Resistant Staphylococcus aureus Proliferation and Biofilm Formation.

ACS omega, 10(11):11386-11396.

Staphylococcus aureus is a bacterium found on the skin and mucous membranes of humans and animals. This micro-organism is classified as an opportunistic pathogen and causes infections in both hospital and community settings. The increase in antibiotic resistance, especially methicillin-resistant S. aureus (MRSA), is a major challenge for clinical and epidemiological practice. The present study aims to investigate the potential antibacterial and antibiofilm activities of the compound [Fe(cyclam)sal]PF6 against drug-resistant strains of S. aureus. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against S. aureus strains ATCC 25904, S. aureus ATCC 33591, and S. aureus 05-0052 were determined for [Fe(cyclam)sal]PF6. First, bacterial abundance, viability, and cell envelope damage in planktonic cultures were investigated in response to this compound. Second, its potential effect on biofilm proliferation and adhesion was evaluated using different approaches: optical density (OD), scanning electron microscopy (SEM), and biochemical analysis of the extracellular polymeric matrix. The complex [Fe(cyclam)sal]PF6 inhibited bacterial growth and induced an increase in cell death. The compound disrupted the integrity of the cell membrane, resulting in the release of cytoplasmic contents into the extracellular medium. Remarkably, the metal complex reduced the pre-established S. aureus biofilm and impaired its adhesion. Furthermore, it is not toxic to mammalian cells. The compound [Fe(cyclam)sal]PF6 affects both the proliferation and biofilm formation of drug-resistant strains of S. aureus, demonstrating strong potential for the design of novel antimicrobial agents.

RevDate: 2025-03-31

Vakili N, Ashengroph M, Sharifi A, et al (2025)

Eco-friendly synthesis of copper nanoparticles by using Ralstonia sp. and their antibacterial, anti-biofilm, and antivirulence activities.

Biochemistry and biophysics reports, 42:101978.

Biosynthesized nanoparticles (NPs) created through environmentally friendly and low-toxicity methods show great potential for various nanotechnology applications. In particular, copper nanoparticles (Cu-NPs) are promising for medical uses. This study aims to explore the eco-friendly synthesis of Cu-NPs and their potential as a novel strategy to combat antimicrobial resistance. Cu-NPs were synthesized using Ralstonia sp. KF264453 and characterized with techniques including ultraviolet-visible (UV-Vis) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The antibacterial properties of the NPs and their synergistic effects with common antibiotics were assessed. The study also investigated their impact on bacterial cell membrane disruption, biofilm formation, efflux pump activity, and motility. UV-Vis analysis indicated a significant absorption peak at 552 nm, confirming surface plasmon resonance (SPR) for Cu-NPs. FESEM images revealed predominantly spherical NPs with an average size of 69.7 nm. DLS measurements indicated a hydrodynamic diameter of 78.2 nm due to stabilizing biomolecules. A zeta potential of -5.1 mV suggested moderate colloidal stability, suitable for short-term biomedical applications. XRD analysis confirmed a face-centered cubic (FCC) crystalline structure with an average crystallite size of 45 nm. FT-IR spectra detected functional groups, indicating that proteins, carbohydrates, lipids, and amino acids may have contributed to the synthesis and stabilization of the NPs. Cu-NPs showed notable antibacterial efficacy, with minimum inhibitory concentrations (MIC) between 0.625 and 5 μg/mL and minimum bactericidal concentrations (MBC) ranging from 5 to 20 μg/mL. They improved the effectiveness of penicillin and cefixime, enhanced membrane permeability, inhibited biofilm formation, disrupted efflux pump activity in Staphylococcus aureus SA-1199B, and decreased swarming motility in Pseudomonas aeruginosa. Cu-NPs demonstrate strong antimicrobial activity, inhibit biofilm formation and efflux pump function, and enhance the effectiveness of conventional antibiotics. While they show promise in combating antimicrobial resistance, further research is needed to assess their clinical potential and safety for medical use.

RevDate: 2025-03-31

Kragh ML, Scheel NH, Leekitcharoenphon P, et al (2025)

Repeated biocide treatments cause changes to the microbiome of a food industry floor drain biofilm model.

Frontiers in microbiology, 16:1542193.

There is a concern about the development of microbial tolerance and resistance to biocides due to their repeated use within the food industry. This study aimed to develop a floor drain biofilm model and test whether repeated biocide treatment would result in increased tolerance to biocides. Culturomics and shotgun metagenomic analysis of 14 drains and 214 bacterial isolates from three industrial food production environments revealed microbiomes with great diversity and complexity, but with the dominance of a few highly abundant taxa, including Pseudomonas. A representative drain biofilm was created (3 days, 15°C) using 31 whole genome sequenced bacterial isolates from 24 genera. The biofilm model represented 47-58% and 76-81% of the microbial abundance observed in the metagenome and viable microbiota, respectively. The biofilm model was exposed on days 3 and 6 to water or different industrial concentrations of benzalkonium chloride (BC), peracetic acid (PAA), or sodium hypochlorite (SH). Analysis of the viable survivors using MALDI-TOF MS and the regrowing biofilms using 16S rRNA amplicon sequencing showed how the diversity of the biofilm decreased but without any change in biocide tolerance as seen in log reductions (CFU/cm[2]). The use of different biocides did, however, exert significantly different selective pressures on the microbiomes as Citrobacter, Acinetobacter, Aeromonas, and Pseudomonas dominated the biofilm after treatments with SH or PAA, while Serratia and Moraxella dominated after treatments with BC. The dominance of Serratia marcescens could be explained by the carriage of a BC efflux pump (oqxB) and the highest (20 mg/L BC) minimum inhibitory concentration (MIC) result of the drain isolates. In contrast, despite carrying a BC efflux pump (qacH), Listeria monocytogenes ST121 did not show increased survival or presence in the biofilm after BC treatments. Only the highest tested concentration of PAA was able to completely eradicate L. monocytogenes. The developed biofilm model and the repeated biocide treatments enabled a better understanding of how biocides affect the biofilm microbiome. Future research should involve testing biocide rotation strategies to control biofilm regrowth and inactivation of persistent foodborne pathogens in floor drains.

RevDate: 2025-04-01

He X, Zhang W, Liu J, et al (2025)

The global regulatory role of RsbUVW in virulence and biofilm formation in MRSA.

Microbial pathogenesis, 203:107508 pii:S0882-4010(25)00233-5 [Epub ahead of print].

The widespread prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has caused serious challenges to clinical treatment. This study was designed to explore effective targets for MRSA prevention and control. The key virulence regulator was screened through the correlation analysis between virulence and various regulatory factors in the main clinical epidemic MRSA. The potential key factors were inactivated to further evaluate the inhibitory effect on the virulence of MRSA standard strain S. aureus ATCC43300 and its influence on drug resistance and biofilm formation. Enterobacterial repetitive intergenic consensus-PCR was used to analyze the clinical epidemic genotypes of MRSA. The virulence of MRSA was evaluated mainly by measuring its adhesion and invasion ability to A549 cells, the lethality to Galleria mellonella larvae, and the transcription level of related genes. The biofilm formation was assessed by crystal violet staining on polystyrene microplates. The results showed that most virulence factors of clinical representative MRSA strain were significantly positively correlated with RsbUVW system. After knocking out the rsbV gene, a key component of the rsbUVW system, the virulence of S. aureus ATCC43300 was significantly reduced (P < 0.05), as indicated by a significant decrease in lethality against G. mellonella larvae and invasion against A549 cells, and a significant decrease in the expression of immune escape related virulence factors polysaccharide intercellular adhesin (PIA) and staphyloxanthin. The biomass and stability of protein-dependent biofilm by S. aureus ATCC43300 were significantly increased. This study will provide useful information for the effective prevention and control of MRSA.

RevDate: 2025-03-29
CmpDate: 2025-03-29

King JC, Lancaster E, Myers A, et al (2025)

Case report: contamination of a drinking water distribution system by Exophiala-dominated biofilm in the Midwestern United States.

Journal of water and health, 23(3):314-321.

Fungal contamination of drinking water distribution systems can impact water quality with implications for public health. We document an instance of Exophiala spp. biofilm contamination of customer taps in the Midwest United States following consumer complaints. Three samples of black biofilm were collected from customer taps in Ohio and then processed using next-generation DNA sequencing of the bacterial 16S and fungal ITS regions. Two samples with successful ITS sequencing were dominated by Exophiala spp., putatively identified as E. cancerae and E. lecanii-corni. Dominant bacterial phyla in samples included Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria. Bacterial composition varied substantially at the family and genus levels, and potentially pathogenic bacteria (i.e., Acinetobacter spp., Legionella spp., Mycobacterium spp., and Pseudomonas spp.) were detected. The potential for fungal contamination of drinking water distribution systems should be evaluated when biofilms are observed.

RevDate: 2025-03-31
CmpDate: 2025-03-29

Szafraniec GM, Chrobak-Chmiel D, Dolka I, et al (2025)

Virulence factors and biofilm forming ability of Staphyloccoccus species isolated from skeletal lesions of broiler chickens.

Scientific reports, 15(1):10807.

Lameness in poultry is a significant issue in modern meat production that adversely affects both animal welfare and economic outcomes due to poor leg health, reduced locomotor function, increased feed conversion ratios, and poor performance. Fast-growing broilers are particularly susceptible to lameness, with Staphylococcus being a major bacterial cause of skeletal infections. The aim of this study was to identify Staphylococcus species isolated from skeletal lesions in broiler chickens and to characterize the factors that facilitate such infections. Bacterial strains were isolated from 25 commercial broiler flocks in eastern Poland. The median prevalence of Staphylococcus in birds per flock was 60%. In total, 47% of the examined chickens and 88% of the examined flocks tested positive for Staphylococcus. The main bone sites affected by staphylococci were the femur (56.7%), femoral head (necrosis) (34.3%), hock joints (9.0%), femoral head (transient necrosis) (9.0%), tibiotarsus (7.5%), foot pads (dermatitis) (3.0%), and stifle (knee) joints (1.5%). Of all 93 Staphylococcus strains, 59% (55/93) were isolated from the femora. Twelve staphylococcal species were identified, all coagulase-negative, where Staphylococcus cohnii (24.7%) was the most prevalent species, followed by S. epidermidis (16.1%), S. hominis (15.1%), S. lentus (10.8%), S. saprophyticus (9.7%), S. chromogenes (8.6%), S. arlettae (4.3%), S. sciuri (4.3%), S. haemolyticus (2.2%), S. xylosus (2.2%), S. carnosus (1.1%), and S. gallinarum (1.1%). Eleven and six different staphylococcal species were implicated in the pathogenesis of femoral and tibiotarsal lesions, respectively. More than one Staphylococcus species was isolated from 47.8% of all Staphylococcus-positive chickens. Nearly all (97.8%) of coagulase-negative staphylococci isolates had biofilm-forming ability, but most of them were categorized as weak biofilm producers. The highest biofilm production was observed in the strains that caused femoral head osteonecrosis and footpad dermatitis. Staphylococcus chromogenes, S. lentus, and S. epidermidis exhibited the highest DNase and/or gelatinase activity. Despite the low prevalence of certain adhesin genes, the eno gene encoding laminin-binding protein was highly represented in staphylococci (75.3%). The study highlights the complex nature of coagulase-negative staphylococcal infections in poultry and underscores the need for further research into their virulence mechanisms and control strategies.

RevDate: 2025-03-28

de Farias Cabral VP, Rodrigues DS, Barbosa AD, et al (2025)

Potential activity of paroxetine alone and associated with oxacillin as an alternative to prevent Staphylococcus aureus biofilm formation in catheters.

Folia microbiologica [Epub ahead of print].

Biofilm formation, especially in medical devices, is a pertinent factor in the virulence of Staphylococcus aureus, and is known to increase morbidity, mortality, and costs. We evaluated the activity of paroxetine, a selective serotonin reuptake inhibitor, alone and associated with oxacillin, a β-lactam antibacterial, against S. aureus biofilms, as well as verified its potential application as a preventive agent against biofilm formation in catheters. The tests were performed against mature and developing biofilms of methicillin-sensitive and -resistant S. aureus using the thiazolyl blue tetrazolium bromide reduction assay. The prevention of biofilm formation in catheters was investigated by counting colony-forming units, and scanning electron microscopy was also performed. Paroxetine caused a significant reduction in cell viability in biofilms, and when associated with oxacillin, significance was verified. Paroxetine alone and associated with oxacillin showed potential for preventing the formation of S. aureus biofilms in peripheral venous catheters, demonstrated by scanning electron microscopy, reaching inhibition of 94.94% in colony-forming units per mL. Paroxetine demonstrated promising potential against S. aureus biofilms in vitro, indicating the possibility of application as a protective agent against the formation of S. aureus biofilms in catheters.

RevDate: 2025-03-28

Xu Z, Premarathna M, Liu J, et al (2025)

Current knowledge on the dual species interaction and biofilm between Aspergillus and Bacillus: exploiting molecular understanding toward applications.

Critical reviews in microbiology [Epub ahead of print].

The complex interaction between Aspergillus and Bacillus has been gaining attention with the evolution of their co-culture applications. Information reported on this interaction from different points of view including both synergistic and antagonistic mechanisms necessitates a review for better understanding. This review focuses on the interaction, biofilm formation, and the diverse biotechnological applications of Aspergillus and Bacillus, giving special attention to Aspergillus niger and Bacillus subtilis. The review demonstrates that co-cultivation of Aspergillus and Bacillus exhibits significant transcriptional changes, impacting metabolism and secondary metabolite production in both organisms. Signaling from living fungal hyphae, EPS production, TasA fibrils, and regulators like Spo0A are essential in forming biofilm communities. Nutrient availability and pH levels, species type, and mutations in EPS-producing genes may also influence whether Bacillus will act antagonistically or synergistically with Aspergillus. This dual-nature complex interaction activates silent genes synthesizing novel compounds mainly with antifungal and medicinal properties, showcasing its potential for diverse applications in various fields such as agriculture and crop protection, bioremediation, environmental biotechnology, food science and fermentation, industrial biotechnology, and medical biotechnology and health. The use of Aspergillus and Bacillus species has evolved from simple monoculture applications to more sophisticated co-cultures and has been trending toward their synergy and metabolic optimization.

RevDate: 2025-03-30

Osta-Ustarroz P, Theobald AJ, KA Whitehead (2025)

Correction: Osta-Ustarroz et al. Microbial Colonization, Biofilm Formation, and Malodour of Washing Machine Surfaces and Fabrics and the Evolution of Detergents in Response to Consumer Demands and Environmental Concerns. Antibiotics 2024, 13, 1227.

Antibiotics (Basel, Switzerland), 14(3):.

In the original publication [...].

RevDate: 2025-03-30

Cholo MC, Feldman C, Anderson R, et al (2025)

Effects of Anti-Pseudomonal Agents, Individually and in Combination, With or Without Clarithromycin, on Growth and Biofilm Formation by Antibiotic-Susceptible and -Resistant Strains of Pseudomonas aeruginosa, and the Impact of Exposure to Cigarette Smoke Condensate.

Antibiotics (Basel, Switzerland), 14(3):.

Background/Objectives:Pseudomonas aeruginosa (Psa) can circumvent antimicrobial chemotherapy, an ability enhanced by cigarette smoking (CS). This study probed potential benefits of combinations of anti-pseudomonal agents, and potential augmentation by a macrolide, in the absence or presence of cigarette smoke condensate (CSC). Methods: Two susceptible (WT: wild-type and DS: drug-sensitive) and one multidrug-resistant (MDR) strains of Psa were treated with amikacin, cefepime, and ciprofloxacin, individually and in combination, and with and without clarithromycin, followed by the measurement of planktonic growth and biofilm formation by spectrophotometry. Antibiotic interactions were determined using the fractional inhibitory concentration index (FICI) method. Effects on preformed biofilm density were measured following the addition of antibiotics: all procedures were performed in the absence and presence of CSC. Results: The minimal inhibitory concentrations (MICs) of the three agents ranged from 0.125 mg/L to 1 mg/L (WT and DS strains) and 16 mg/L to 64 mg/L (MDR strain), with all resistant to clarithromycin (125 mg/L). MIC values closely correlated with the antibiotic concentrations required to inhibit biofilm formation. FICI revealed synergism between most combinations, with augmentation by clarithromycin. Amikacin had the greatest effect on biofilm density, which was potentiated by combination with the other antibiotics, particularly clarithromycin. Exposure to CSC had variable, albeit modest, effects on bacterial growth and biofilm formation, but low concentrations increased biofilm mass and attenuated synergistic antimicrobial interactions and effects on biofilm density. Conclusions: Amikacin, cefepime, and ciprofloxacin, especially with clarithromycin, exhibit synergistic anti-pseudomonal activity and decrease preformed biofilm density. CSC attenuated these effects, illustrating the pro-infective potential of CS.

RevDate: 2025-03-30

Dawan J, Zhang S, J Ahn (2025)

Recent Advances in Biofilm Control Technologies for the Food Industry.

Antibiotics (Basel, Switzerland), 14(3):.

Biofilms remain a major challenge in the food industry due to the increased resistance of foodborne pathogens to antimicrobial agents and food processing stresses, leading to food contamination and significant health risks. Their resistance to preservation techniques, antimicrobial treatments, and processing conditions increases concerns regarding food safety. This review discusses recent developments in physical, chemical, and surface modification strategies to control and remove biofilms in food processing environments. Physical methods, such as thermal treatments, electric fields, and ultrasonic systems, have demonstrated their efficacy in disrupting biofilm structure and improving disinfection processes. Chemical treatments, including the use of sanitizers, disinfectants, acidulants, and enzymes, provide targeted approaches to degrade biofilm matrices and inhibit bacterial adhesion. Furthermore, surface modifications of food contact materials provide innovative solutions for preventing biofilm formation and enhancing food safety. These cutting-edge strategies not only improve food safety but also reduce contamination risk in food processing facilities. The review highlights the mechanisms, efficacy, and applicability of these techniques, emphasizing their potential to mitigate biofilm-associated risks and ensure food quality and safety.

RevDate: 2025-03-30

Mitsuwan W, Boripun R, Saengsawang P, et al (2025)

Multidrug Resistance, Biofilm-Forming Ability, and Molecular Characterization of Vibrio Species Isolated from Foods in Thailand.

Antibiotics (Basel, Switzerland), 14(3):.

BACKGROUND: Vibrio species are common foodborne pathogens that cause gastrointestinal tract inflammation. Multidrug resistance (MDR) in Vibrio spp. is a global health concern, especially in aquaculture systems and food chain systems. This study aimed to detect Vibrio contamination in food collected from 14 markets in Nakhon Si Thammarat, Thailand, and determine their antibiotic susceptibility.

METHODS: One hundred and thirty-six food samples were investigated for Vibrio contamination. All isolates were tested for antibiogram and biofilm-forming ability. Moreover, the ceftazidime or cefotaxime resistance isolates were additionally investigated for extended-spectrum β-lactamase (ESBL) producers. The isolates were additionally examined for the presence of antibiotic resistance genes. The ESBL-suspected isolates with moderate-to-high biofilm-forming ability were further analyzed for their whole genome.

RESULTS: The prevalence of Vibrio contamination in food samples was 42.65%, with V. parahaemolyticus demonstrating the highest prevalence. Most isolates were resistant to β-lactam antibiotics, followed by aminoglycosides. The overall MDR of isolated Vibrio was 18.29%, with an average multiple antibiotic resistance (MAR) index of 16.41%. Most isolates were found to have β-lactam resistance-related genes (blaTEM) for 41.46%, followed by aminoglycoside resistance genes (aac(6')-Ib) for 18.29%. Most Vibrio showed moderate to strong biofilm-forming ability, particularly in MDR isolates (92.86%). Two ESBL-suspected isolates, one V. parahaemolyticus isolate and one V. navarrensis, were sequenced. Interestingly, V. parahaemolyticus was an ESBL producer that harbored the blaCTX-M-55 gene located in the mobile genetic element region. While V. navarrensis was not ESBL producer, this isolate carried the blaAmpC gene in the region of horizontal gene transfer event. Remarkably, the Inoviridae sp. DNA integration event was present in two Vibrio genomes.

CONCLUSIONS: These findings impact the understanding of antibiotic-resistant Vibrio spp. in food samples, which could be applied for implementing control measures in aquaculture farming and food safety plans.

RevDate: 2025-03-28
CmpDate: 2025-03-28

Karthikeyan A, Tabassum N, Jeong GJ, et al (2025)

Alleviation of mycobacterial infection by impairing motility and biofilm formation via natural and synthetic molecules.

World journal of microbiology & biotechnology, 41(4):113.

Mycobacterium species show distinctive characteristics with significant medical implications. Mycobacteria, including Mycobacterium tuberculosis and non-tuberculous mycobacteria, can form biofilms that facilitate their survival in hostile environments and contribute to development of antibiotic resistance and responses by the host immune system. Mycobacterial biofilm development is a complex process involving multiple genetic determinants, notably mmpL genes, which regulate lipid transport and support cell wall integrity, and the groEL gene, which is essential for biofilm maturation. Sliding motility, a passive form of surface movement observed across various mycobacterial species, is closely associated with biofilm formation and colony morphology. The unique sliding motility and biofilm-forming capabilities of Mycobacterium spp. are pivotal for their pathogenicity and persistence in diverse environments. A comprehensive understanding of the regulatory mechanisms governing these processes is crucial for the development of novel therapeutic strategies against mycobacterial infections. This review provides a detailed examination of our current knowledge regarding mycobacterial biofilm formation and motility, with a focus on regulation of these processes, their impact on pathogenicity, and potential avenues for therapeutic intervention. To this end, the potential of natural and synthetic compounds, including nanomaterials, in combating mycobacterial biofilms and inhibiting sliding motility are discussed as well. These compounds offer new avenues for the treatment of drug-resistant mycobacterial infections.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Huang Y, Miao H, Lv Y, et al (2025)

Aspirin Combined with Antifungal Drugs Suppresses Candida albicans Biofilm by Activating Autophagy.

Journal of microbiology and biotechnology, 35:e2411060 pii:jmb.2411.11060.

Aspirin (ASA) induces autophagic death of human tumor cells and autophagy changes the susceptibility of Candida albicans biofilm to antifungal agents. This study investigates whether ASA suppresses C. albicans biofilm by autophagy regulation and its combination effect with antifungals. Biofilm sensitivity to ASA alone and in combination with antifungals was evaluated using the checkerboard method, and drug interactions were assessed by the fractional inhibition concentration index (FICI) and ΔE models. The effects of ASA on mTOR signaling were examined by western blotting. Alkaline phosphatase activity, acridine orange stain assay, and autophagy-related gene expressions were examined to evaluate autophagic activity. Autophagosomes were observed by transmission electron microscopy. Reactive oxygen species (ROS) were detected by DCFH-DA. Mitochondrial membrane potential (MMP), malondialdehyde (MDA), and ATP levels were determined using commercial kits. ASA inhibited C. albicans biofilm in a concentration dependent manner and showed synergistic effects against biofilms when combined with amphotericin B or 5-fluorocytosine. ASA treatment induced oxidative stress, evidenced by increased ROS and MDA levels, alongside a reduction in ATP and MMP. ASA inhibited mTOR signaling and induced autophagy in C. albicans biofilms by increasing oxidative stress and mitochondrial dysfunction, contributing to biofilm inhibition. This study provides valuable insights into the potential of ASA as an adjunct therapy in combination with antifungal agents for managing C. albicans biofilm-related infections.

RevDate: 2025-03-27

Wang Y, Wang Z, Li Q, et al (2025)

A "three-in-one" thermosensitive gel system that enhances mucus and biofilm penetration for the treatment of vulvovaginal candidiasis.

Journal of controlled release : official journal of the Controlled Release Society pii:S0168-3659(25)00286-X [Epub ahead of print].

The special physiological barriers of women, such as vaginal mucus and self-cleaning behavior, pose great challenges for the treatment of vulvovaginal candidiasis (VVC), and the drug resistance caused by fungal biofilms limits the application of existing antifungal drugs. Based on this, we designed a "three-in-one" thermosensitive gel system (AF/BP Gel) loaded with antibiofilm nanoparticles (AF NPs) and mucus penetration-assisting nanoparticles (BP NPs) to achieve vaginal adhesion while enhancing mucus and biofilm penetration. AF NPs were loaded with farnesol (FAR) and amphotericin B (AMB), and FAR is one of quorum sensing molecules which can interfere with biofilm-related genes such as ALS3, HWP1, RAS1, CPH1, EFG1, NRG1, TUP1, UME6, and disperse mature biofilm, thus playing a synergic antibiofilm role with AMB. BP NPs was loaded with bromelain (BRO), which cleared the mucus barrier for AF NPs and help it penetrate deep into the infection. These two kinds of nanoparticles use the thermosensitive gel matrix to reach the surface of the vaginal mucosa uniformly and persistently to overcome the obstacle of vaginal self-cleaning. AF/BP Gel showed great anti-candida albicans activity in vitro and in vivo, and greatly improved the inflammatory conditions in VVC mice. Overall, this "three-in-one" thermosensitive gel system can overcome multiple physiological barriers and resist different periods of biofilm, providing a new platform for treating vagina-associated infections.

RevDate: 2025-03-27

Mi L, Xu T, Peng YY, et al (2025)

Tetracationic tetraaryltetranaphtho[2,3]porphyrins for photodynamic inactivation against Staphylococcus aureus biofilm.

European journal of medicinal chemistry, 290:117558 pii:S0223-5234(25)00323-X [Epub ahead of print].

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising strategy for addressing bacterial infections, particularly those involving biofilm formation. The electrostatic attraction between the negatively charged bacterial cell walls and the cationic charges of photosensitizers facilitates the accumulation of PSs on bacterial surfaces, thereby enhancing aPDT efficacy. In this study, three series of tetracationic tetraaryltetranaphtho[2,3]porphyrins (TNPs), each incorporating different cationic groups with alkyl chains of varying lengths, were designed and synthesized. Their photodynamic inactivation efficacy against S. aureus, E. coli and C. albicans was evaluated, respectively. These TNPs exhibited strong absorption at ∼730 nm with high molar extinction coefficients (>51,500 L·mol[-1]·cm[-1]), fluorescence emission at ∼758 nm and efficient singlet oxygen generation capabilities. Among them, TNPs with shorter alkyl chains (I1, II1 and Ⅲ1) exhibited enhanced phototoxicity against planktonic microbes, with I1 (containing pyridinium substituents) showing the highest activity. These three compounds effectively disrupted mature S. aureus biofilms, with Ⅲ1 (bearing diethylmethylammonium groups) demonstrating superior biofilm eradication capabilities. These findings highlight the dual antibacterial and biofilm-disrupting potential of these Ar4TNP derivatives. Furthermore, their selective toxicity toward bacterial cells over mammalian cells at therapeutic doses provides a foundation for developing safer antimicrobial agents, offering promising alternatives to antibiotics for tackling drug-resistant pathogens and persistent biofilm-associated infections.

RevDate: 2025-03-27

Dicataldo G, Desmond P, Al-Maas M, et al (2025)

Feasibility and application of membrane aerated biofilm reactors for industrial wastewater treatment.

Water research, 280:123523 pii:S0043-1354(25)00436-1 [Epub ahead of print].

Membrane aerated biofilm reactors (MABRs) have emerged as a promising technology for wastewater treatment, offering significant advantages over conventional activated sludge (CAS) systems. Over the past decades, membrane processes have revolutionized municipal water treatment with membrane bioreactors (MBRs) becoming a widely accepted process for municipal and then industrial wastewater (IW) treatment. By the same token, MABR technologies were initially applied to municipal wastewater; however, their application in industrial settings is still emerging. Despite the promise of MABRs due to the biofilm's tolerance to IW toxins, there is a lack of information on their industrial applications. Therefore, this paper critically reviews the feasibility and application of MABRs for IW treatment, including pharmaceutical, chemical, refinery, petrochemical, oilfield, landfill leachate and other complex industrial waters. Three existing technology vendors with full-scale experience were compared; however, additional providers with innovative designs may provide step-changes in performance. Key outcomes highlight the effectiveness of MABRs in reducing carbon, nitrogen, and xenobiotics from high-strength IWs at bench and pilot scales. Critical factors influencing MABR performance, such as biofilm thickness (BT) were correlated to organics and nitrogen removal efficiency in industrial applications. Review of advances in MABR modeling techniques showed that current models lack the needed resolution for large and dynamic industrial systems. Additionally, the review compares municipal and industrial applications of MABRs, emphasizing the unique challenges and innovations required for their adoption in IW treatment. Overall, the MABR process was found to be feasible for industrial applications with pilot and/or demonstration-scale testing being necessary to further optimize process performance.

RevDate: 2025-03-27

Campus G, Cagetti MG, Lehrkinder A, et al (2025)

The Probiotic Effects of Lactobacillus brevis CD2 on Caries Related Variables of Dental Plaque Biofilm.

International dental journal, 75(3):1662-1671 pii:S0020-6539(25)00059-0 [Epub ahead of print].

OBJECTIVES: This study was based on the research question: "Does L. brevis CD2 have an effect on the acidogenicity of sugar-exposed bacteria? To solve this question, a multistep study was planned: first, an in vitro investigation aimed to assess the acid production of monoculture bacterial solutions; and second, an ex vivo experiment to evaluate the production or inhibition of acids from plaque samples.

METHODS: L. brevis CD2 and several control strains (Lactobacillus brevis CD2, Lactobacillus reuteri DSM 17938, Lactobacillus rhamnosus LB21, Lactobacillus plantarum 931, Streptococcus mutans Ingbritt) were tested with various sugars; pH changes were recorded at specific time points using a micro-pH electrode. Additionally, for the ex vivo phase, the same sugars were added to equal amounts of pooled plaque from 9 healthy subjects with bacterial suspensions, as well as a control solution, and pH was monitored for up to 90 minutes. For the ex vivo phase, 9 adults were randomised in a crossover design for 28 days. For the in vivo phase, 26 healthy subjects used 1/2 lozenges 3 times daily containing either L. brevis CD2 (active) or no probiotic bacteria (placebo). Plaque acidogenicity was assessed using the microtouch method after a 10 ml mouth rinse containing 10% sucrose for 1 minute (on day 0 and day 28).

RESULTS: L. brevis CD2 exhibited the highest ability to inhibit the fermentation of fructose, lactose, and sucrose compared to the control strains (P < .05). A significant reduction in plaque acidogenicity was observed in vivo from day 0 to day 28 in the test group (P < .05).

CONCLUSIONS: This study indicates that L. brevis CD2 mitgates the acidogenic attributes of plaque biofilm organisma in vitro, in vivo and ex vivo, suggesting its potential benefit as a caries preventive probiotic agent.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Wang YJ, Wang F, Jiang MH, et al (2025)

Oxirapentyn A, Derived from Marine Amphichorda felina, Effectively Inhibits Quorum Sensing and Biofilm Formation Against Chromobacterium violaceum.

Current microbiology, 82(5):215.

The emergence of multidrug-resistant Chromobacterium violaceum, an opportunistic pathogen, poses a significant threat to human, animal, and environmental health, underscoring the urgent need for innovative strategies. Marine-derived natural compounds have gained attention as a promising source of quorum sensing inhibitors (QSIs) that can attenuate C. violaceum virulence without inducing resistance. This study reports, for the first time, the anti-quorum sensing (anti-QS) and anti-biofilm activities of oxirapentyn A, one marine natural compound, against C. violaceum. Results demonstrate oxirapentyn A (200 μg/mL) significantly inhibits biofilm formation, violacein production, and hemolysin synthesis by 48.8, 21.7, and 22.3%, respectively. Scanning electron microscopy (SEM) further corroborated the disruption of biofilm architecture. LC-MS analysis revealed a concentration-dependent reduction in the production of N-decanoyl-homoserine lactone (C10-HSL), a key QS signaling molecule. Furthermore, RT-qPCR analysis indicated oxirapentyn A downregulated critical QS-related genes (cviI, cviR, vioA, chiA, and pykF) by 20.7, 36.6, 31.1, 66.6, and 30.7%, respectively. Notably, in vivo experiments demonstrated that oxirapentyn A significantly improved the survival of Galleria mellonella larvae infected with C. violaceum. Collectively, these findings highlight oxirapentyn A as a novel QSI with dual anti-QS and biofilm-disrupting activities, offering a promising strategy to combat drug-resistant bacterial infections.

RevDate: 2025-03-27

Pietz A, John K, U Thiele (2025)

The role of substrate mechanics in osmotic biofilm spreading.

Soft matter [Epub ahead of print].

Bacteria invade surfaces by forming dense colonies encased in a polymer matrix. Successful settlement of founder bacteria, early microcolony development and later macroscopic spreading of these biofilms on surfaces rely on complex physical mechanisms. Recent data show that on soft hydrogels, substrate rigidity is an important determinant for biofilm initiation and spreading, through mostly unknown mechanisms. Using a thermodynamically consistent thin-film approach for suspensions on soft elastic surfaces supplemented with biomass production we investigate in silico the role of substrate softness in the osmotic spreading of biofilms. We show that on soft substrates with an imposed osmotic pressure spreading is considerably slowed down and may be completely halted depending on the biomass production rate. We find that the critical slowing down of biofilm spreading on soft surfaces is caused by a reduced osmotic influx of solvent into the biofilm at the edges, which results from the thermodynamic coupling between substrate deformation and interfacial forces. By linking substrate osmotic pressure and mechanical softness through scaling laws, our simple model semi-quantitatively captures a range of experimentally observed biofilm spreading dynamics on hydrogels with different architectures, underscoring the importance of inherent substrate properties in the spreading process.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Jungbauer G, Lechner R, Stähli A, et al (2025)

In-Vitro Effect of Manuka Honey / Propolis Toothpastes on Bacteria and Biofilm Associated with Caries and Gingivitis.

Oral health & preventive dentistry, 23:203-210 pii:6094827.

PURPOSE: To investigate the antibacterial and anti-biofilm effects of two Manuka honey toothpaste formulations containing propolis (Manuka prop) or fluoride (Manuka F), in comparison with the toothpaste base (TP con) and a commercial toothpaste (TP com), on oral bacteria and biofilm.

MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of the formulations and controls were tested against five oral bacterial species. Both the effect on a multispecies dental biofilm precultured for 3.5 days as well as the inhibition of de-novo biofilm formation up to 24 h were investigated. Test substances at concentrations of 20%, 10% and 5% were applied to preformed biofilm for 1 min. The reduction in colony-forming units (cfu), metabolic activity, and biofilm mass were determined. Similarly, the test substances were applied to surfaces for 30 min before bacteria and media were added. The reduction of a tetrazolium dye (MTT assay) was used to assess cytotoxicity on gingival fibroblasts.

RESULTS: The MIC values of all toothpaste formulations including TP con were very low with the highest MIC of 0.04%. In precultured biofilms, both the number of colony forming units (cfu) and metabolic activity decreased following addition of any toothpaste. The greatest reductions of cfu were found after addition of 20% TP com (by about 6 log10) and after 20% Manuka prop (by about 2.3 log10). However, the biofilm mass was not reduced. Coating the surface with toothpaste formulation, the cfu in the newly formed biofilm decreased in a concentration-dependent manner, with TP com being most active. Both 20% of Manuka prop and Manuka F reduced the cfu counts more than the TP con at 24 h. The toothpaste formulations affected the viability of gingival fibroblasts in a concentration-dependent manner, with no differences observed among the formulations.

CONCLUSION: The Manuka-honey containing toothpastes might be an alternative to toothpaste containing conventional chemical agents. Further research is needed to clinically examine the effect on caries and gingivitis prevention.

RevDate: 2025-03-27

Ge T, Wu R, Yu T, et al (2025)

Halogen anion modulated metal-organic frameworks with enhanced nanozyme activities for bacterial biofilm disruption.

Nanoscale [Epub ahead of print].

There is an urgent need to develop new nanozymes with enhanced catalytic activities to combat bacterial infections, which have become increasingly challenging due to the misuse of antibiotics and the difficulties of new antibiotic discovery. Here, we employed a new strategy against bacterial biofilms by introducing halide anions to modulate the crystal facets of ZIF-L metal-organic frameworks (MOFs) and then loading chloroquine to form Ch@ZIF-L. The modulation of crystal facets significantly enhanced the oxidase activities of ZIF-L, which can be significantly changed by modulation of its crystal facets, with the hexagonal ZIF-L (ZIF-L-H-Cl) structure showing the highest oxidase activity. At pH 6.0, over 80% of chloroquine was released from Ch@ZIF-L-H-Cl within 8 hours, altering the DNA conformation of bacterial biofilms and disrupting the extracellular polymeric substances (EPSs). The generation of singlet oxygen catalyzed by ZIF-L-H-Cl can effectively kill bacteria at the infected wound site. The composite nanozyme of Ch@ZIF-L-H-Cl, when treated at 100 μg mL[-1], exhibited no adverse effects on normal cell growth or hemolysis. Our in vivo experiments demonstrated an 85% reduction of the wound area by day 8 and a rapid recovery of body weight in mice with wounds infected with Staphylococcus aureus (S. aureus) biofilms. Furthermore, substantial reductions in bacterial counts were observed in both wounds and blood samples in the mice, highlighting the great potential of Ch@ZIF-L-H-Cl in combating bacterial biofilm infections.

RevDate: 2025-03-27

Mu X, Liu K, Yang J, et al (2025)

From De Novo Conceived Small Molecules to Multifunctional Supramolecular Nanoparticles: Dual Biofilm and T3SS Intervention, Enhanced Foliar Affinity, and Effective Rice Disease Control.

Advanced science (Weinheim, Baden-Wurttemberg, Germany) [Epub ahead of print].

Conventional antimicrobials typically exhibit suboptimal deposition on rice leaves, resulting in poor efficacy, further impaired by biofilms and Type III Secretion Systems (T3SS). Herein, this study presents a supramolecular strategy to fabricate BtP27@β-CD, a sunflower-like material engineered through host-guest recognition between de novo designed molecule BtP27 and β-cyclodextrin. BtP27@β-CD manifests enhanced foliar affinity and in vivo efficiency, demonstrating superior protective (62.67%) and curative (51.16%) activities against bacterial leaf blight at a low-dose of 200 µg mL[-1] compared to commercial thiodiazole-copper (37.78%/38.13%) without compromising safety. This multifunctional material, structurally derived from dufulin, inherit progenitor's systemic and conductive properties, alongside the capacity to activate salicylic acid-mediated plant defense pathways. Moreover, it is endowed with the anticipated abilities to disorganize biofilm barriers, annihilate encased pathogens, and inhibit T3SS. This constitutes the inaugural report of a supramolecular-based biofilm/T3SS dual inhibitor. An expanded investigation into substrate and indication screening identified additional molecules that self-assemble with β-cyclodextrin to form supramolecular materials, exhibiting superior potency against other rice diseases, with protective potency ranging from 63.53% to 73.30% and curative efficacy spanning 42.18% to 60.41% at 200 µg mL[-1]. In brief, this work establishes a paradigm for designing guest molecules from scratch to construct supramolecular materials with tailored characteristics.

RevDate: 2025-03-27

Lin Z, Ruan C, Xia R, et al (2025)

Bacterium-Phage Interactions Enhance Biofilm Resilience during Membrane Filtration Biofouling under Oxidative and Hydraulic Stresses.

Environmental science & technology [Epub ahead of print].

Microbial interactions on membrane surfaces can facilitate biofilm formation and biofouling, which poses a significant challenge for pressure-driven membrane filtration systems. This multiomics study investigates the adaptive responses of bacterium-phage interactions under varying oxidative and hydraulic stress during membrane backwashing and their biological contributions to biofouling. Oxidative and hydraulic stress distinctly shaped bacteria and phage diversity and community composition. Under moderate oxidative backwashing (300 ppm of NaClO), diversity was maintained, with increased antioxidant enzyme activities, extracellular polymeric substance (EPS) production, and quorum sensing (QS) signaling, promoting bacterial resilience and biofilm formation. In contrast, excessive oxidative stress (600 ppm of NaClO) reduced bacteria and phage diversity, disrupted antioxidant responses, and increased microbial sensitivity. Hydraulic stress predominantly influenced viral diversity and co-occurrence network topology, favoring the expansion of broad host-range phages and lysogenic lifestyles under combined stresses. Phage-bacterium interaction analyses highlighted phages' adaptive preferences for hosts with high network centrality and broad ecological niches, which enhanced microbial interactions and resilience. Transcriptomic profiling demonstrated the early enrichment of genes associated with energy metabolism, ROS detoxification, and biofilm formation, followed by stabilization as biofilms matured. Phage-encoded auxiliary metabolic genes were involved in DNA repair, QS, and EPS biosynthesis, contributing to microbial adaptation through oxidative stress resistance and biofilm stabilization. Overall, these findings provide mechanistic insights into biofouling dynamics and highlight the need to optimize chlorine dosing to prevent suboptimal levels of microbial adaptation and biofouling.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Gugliani A, Taneja S, Shetty DC, et al (2025)

Effect of Various Disinfection Protocols on Endodontic Biofilm and Growth Factors Release from Radicular Dentin: An In Vitro Study.

European endodontic journal, 10(1):1-10.

OBJECTIVE: The aim of this study was to evaluate and compare the effect of various disinfection protocols on bacterial biofilm and subsequent release of growth factors from radicular dentin.

METHODS: One hundred and ninety two extracted single rooted premolars were obtained and contaminated with E. faecalis biofilm for 21 days. The samples were then divided into three main groups - Group I: Irrigation (I) only, Group II: Calcium hydroxide (CH) placement followed by final irrigation and Group III: Triple Antibiotic paste (TAP) placement followed by final irrigation. Each group was further then divided into four sub-groups according to the final irrigating solution used - Sub group A: Saline, Sub group B: 17% EDTA, Sub group C: 1% phytic acid and Sub group D: 0.2%. chitosan nanoparticles. After treatment, the samples were subjected to colony-forming unit (CFU) analysis to determine bacterial reduction and the release of TGF-β1 and VEGF from the root canals, which was quantified using Enzyme-Linked Immunosorbent Assay (ELISA). The data were analyzed using statistical tests.

RESULTS: The maximum reduction in E. faecalis biofilm was observed in Group III (TAP), followed by Group II (CH), and finally Group I (irrigation only). Among the subgroups, the maximum reduction in bacterial biofilm was seen with chitosan nanoparticles, followed by phytic acid, EDTA, and saline. After 24 hours, the highest release of both TGF-β1 and VEGF was observed in the chitosan nanoparticles subgroup, followed by phytic acid, EDTA, and saline. Similar results were seen in the CH and TAP groups.

CONCLUSION: The study concluded that newer irrigating solutions, particularly 0.2% chitosan nanoparticles, showed superior antibacterial activity and better smear layer removal, leading to greater growth factor release from the radicular dentin. The study also highlighted that TAP placement resulted in maximum bacterial reduction, regardless of the final irrigant used. Furthermore, the release of TGF-β1 was significantly higher than VEGF in all groups. (EEJ-2024-03-045).

RevDate: 2025-03-27

Jashrapuria K, SP Singh (2025)

Biofilm Inhibition by Laser-Induced Graphene: Impact of Surface Texture on Rod-Shaped E. coli and Coccus-Shaped Staphylococcus.

ACS applied materials & interfaces [Epub ahead of print].

Biofilm formation poses persistent challenges across various industrial sectors, such as food, marine, and membrane industries, often leading to reduced system performance. An antibiofilm strategy using nanotextured surfaces, such as laser-induced graphene (LIG), has emerged as a potent antibiofilm surface, particularly against rod-shaped bacteria. However, biofilms in nature consist of diverse bacterial species, necessitating a thorough evaluation of LIG efficacy against various bacterial species. Therefore, this study comprehensively analyzed the antibiofilm potential of LIG nanofibers fabricated on polyether sulfone (PES) film. The study focused on two bacterial species with distinct morphologies: rod-shaped Escherichia coli and coccus-shaped Staphylococcus epidermidis. The antibiofilm potential of LIG was studied under extended biofilm-promoting conditions for 10 days. The surface with crushed LIG nanofibers (C-LIG) showed substantial biofilm accumulation, with live biomass of ∼7 μm[3] μm[-2] for E. coli and ∼6 μm[3] μm[-2] for S. epidermidis. In contrast, LIG nanofibers prevented biofilm formation for both species. We also observed LIG-induced cell size alteration for rod- and coccus-shaped bacterial cells. Notably, there was an ∼39% reduction in E. coli cell size compared to the control PES, resulting in a morphological shift to an ovoid shape, likely due to activation of the General Stress Response (GSR). However, S. epidermidis did not exhibit any morphological changes. We also provided the first evidence that E. coli cells exposed to LIG-induced stress regained their original size when cultured in a stress-free environment, indicating these morphological changes were reversible. Further, whole-genome sequencing supported this observation by showing no single nucleotide polymorphism, indicating no permanent genetic alterations in stressed E. coli cells. Overall results showed that LIG nanofibers disrupted biofilm formation in both bacterial species. Thus, our findings highlight the potential of LIG as a robust antibiofilm surface that offers broader applicability in biofilm-prone environments.

RevDate: 2025-03-27

Altuwaijri N, Fitaihi R, Alkathiri FA, et al (2025)

Assessing the Antibacterial Potential and Biofilm Inhibition Capability of Atorvastatin-Loaded Nanostructured Lipid Carriers via Crystal Violet Assay.

Pharmaceuticals (Basel, Switzerland), 18(3): pii:ph18030417.

Background/Objectives: Atorvastatin (ATR), an antihyperlipidemic drug with a potential antibacterial effect, was investigated in this study. Like other statins, ATR has been repurposed for several uses, ranging from anti-inflammatory to antimicrobial applications, and has demonstrated successful results. However, the efficacy of ATR is limited by its low solubility, indicating an opportunity for its encapsulation in a nanotechnology-based drug delivery system. Methods: Nanostructured lipid carrier (NLC) formulations were prepared using high-pressure homogenization and ultrasonication. The formulations were characterized, including their particle size, polydispersity index, zeta potential, encapsulation efficiency, and in vitro release. Antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) was evaluated using the growth curve (bacterial growth over time) and well diffusion methods (zone of inhibition and minimum inhibitory concentration (MIC) determination). The crystal violet assay was employed to assess biofilm inhibition. Results: The NLC formulations were optimized, and the size and zeta potential of the blank nanoparticles were 130 ± 8.39 nm and -35 ± 0.5 mV, respectively. In comparison, the encapsulated NLCs had a size of 142 ± 52.20 nm and a zeta potential of -31 ± 1.41 mV. The average encapsulation efficiency was 94%, and 70% of the drug was released after 24 h. The ATR-loaded NLCs showed significantly enhanced antibacterial activity by reducing the minimum inhibitory concentration by 2.5-fold for E. coli, 1.8-fold for S. aureus, and 1.4-fold for MRSA, and promoting more effective bacterial growth inhibition. Notably, biofilm inhibition was significantly improved with ATR-NLCs, achieving 80% inhibition for S. aureus, 40% for E. coli, and 30% for MRSA, compared to free ATR (p < 0.001). These findings suggest that NLC encapsulation enhances ATR's antimicrobial efficacy and biofilm suppression. Conclusions: This study identified NLCs as successful carriers of ATR, significantly enhancing its antibacterial efficacy and biofilm inhibition capabilities. This formulation, which shows antimicrobial potential against both Gram-positive and Gram-negative bacteria, should be further studied and developed against different resistant microbial strains.

RevDate: 2025-03-27

Rühl-Teichner J, Müller D, Stamm I, et al (2025)

Inhibitory Effect of Antimicrobial Peptides Bac7(17), PAsmr5-17 and PAβN on Bacterial Growth and Biofilm Formation of Multidrug-Resistant Acinetobacter baumannii.

Microorganisms, 13(3): pii:microorganisms13030639.

Acinetobacter (A.) baumannii is a major nosocomial pathogen in human and veterinary medicine. The emergence of certain international clones (ICs), often with multidrug-resistant (MDR) phenotypes and biofilm formation (BF), facilitates its spread in clinical environments. The global rise in antimicrobial resistance demands alternative treatment strategies, such as antimicrobial peptides (AMPs). In this study, 45 human and companion animal MDR-A. baumannii isolates, belonging to the globally spread IC1, IC2 and IC7, were tested for antimicrobial resistance and biofilm-associated genes (BAGs) and their capacity for BF. Of these, 13 were used to test the inhibitory effect of AMPs on bacterial growth (BG) and BF through the application of a crystal violet assay. The two novel AMP variants Bac7(17) (target cell inactivation) and Pasmr5-17 (efflux pump inhibition) and the well-known AMP phenylalanine-arginine-β-naphthylamide (PAβN) were tested at concentrations of 1.95 to 1000 µg/mL. Based on whole-genome sequence data, identical patterns of BAGs were detected within the same IC. AMPs inhibited BG and BF in a dose-dependent manner. Bac7(17) and PAsmr5-17 were highly effective against BG, with growth inhibition (GI) of >99% (62.5 and 125 µg/mL, respectively). PAβN achieved only 95.7% GI at 1000 µg/mL. Similar results were obtained for BF. Differences between the ICs were found for both GI and BF when influenced by AMPs. PAsmr5-17 had hardly any inhibitory effect on the BF of IC1 isolates, but for IC2 and IC7 isolates, 31.25 µg/mL was sufficient. Our data show that the susceptibility of animal MDR-A. baumannii to AMPs most likely resembles that of human isolates, depending on their assignment to a particular IC. Even low concentrations of AMPs had a significant effect on BG. Therefore, AMPs represent a promising alternative in the treatment of MDR-A. baumannii, either as the sole therapy or in combination with antibiotics.

RevDate: 2025-03-27

Zhao F, Mao Y, Yang J, et al (2025)

Enhancing Bacillus thuringiensis Performance: Fertilizer-Driven Improvements in Biofilm Formation, UV Protection, and Pest Control Efficacy.

Microorganisms, 13(3): pii:microorganisms13030499.

This study investigated the effects of fertilizers on the biofilm formation, ultraviolet (UV) resistance, and insecticidal activity of Bacillus thuringiensis (Bt). Bacillus thuringiensis, a widely used microbial pesticide, has a minimal environmental impact and is highly effective against specific pests but is susceptible to environmental factors in field applications. Bacterial biofilms provide protection for Bt, enhancing its survival and functionality in the environment. However, the mechanisms by which fertilizers regulate the characteristics of microbial pesticides and enhance biofilm formation are not well understood. This study evaluated the effects of six fertilizers on the bacterial biofilm formation, the UV resistance, and the insecticidal activities of Bt wettable powders. The results demonstrated that fertilizers significantly enhanced the performance of three Bt preparations (Lv'an, Kang'xin, and Lu'kang). A compound fertilizer with 8.346 g/L of KCl, 2.751 g/L of ZnSO4·7H2O, and 25.681 μL/mL of humic acid was identified by response surface optimization, achieving the maximum BBF formation with OD595 value of 2.738. Furthermore, KH2PO4, HA, and ZnSO4·7H2O notably improved the survivability of Bt preparations under prolonged UV exposure, with the compound fertilizer providing the greatest protection. What's more, fertilizers reduced the LC50 values of all Bt preparations, with the compound fertilizer decreasing the LC50 of the Lv'an Bt wettable powder to 0.139 g/L, a 3.12-fold increase in efficacy. This study demonstrated that fertilizers significantly enhance the UV resistance and insecticidal activity of Bt wettable powders by promoting bacterial biofilm formation. Herein, this study provides new strategies and theoretical support for Bt applications in modern sustainable agriculture.

RevDate: 2025-03-27

Chao C, Gong S, Y Xie (2025)

The Performance of a Multi-Stage Surface Flow Constructed Wetland for the Treatment of Aquaculture Wastewater and Changes in Epiphytic Biofilm Formation.

Microorganisms, 13(3): pii:microorganisms13030494.

Constructed wetlands play a critical role in mitigating aquaculture wastewater pollution. However, the comprehensive treatment performance of aquatic plants and microorganisms under various water treatment processes remains insufficiently understood. Here, a multi-stage surface flow constructed wetland (SFCW) comprising four different aquatic plant species, along with aeration and biofiltration membrane technologies, was investigated to explore the combined effects of aquatic plants and epiphytic biofilms on wastewater removal efficiency across different vegetation periods and treatment processes. The results demonstrated that the total removal efficiency consistently exceeded 60% in both vegetation periods, effectively intercepting a range of pollutants present in aquaculture wastewater. Changes in the vegetation period influenced the performance of the SFCW, with the system's ability to treat total nitrogen becoming more stable over time. The removal efficiency of the treatment pond planted with submerged plants was highest in July, while the pond planted with emergent plants showed an increased removal rate in November. The aeration pond played a significant role in enhancing dissolved oxygen levels, thereby improving phosphorus removal in July and nitrogen removal in November. Additionally, the α-diversity of epiphytic bacteria in the aeration and biofiltration ponds was significantly higher compared to other ponds. In terms of bacterial composition, the abundance of Firmicutes was notably higher in July, whereas Nitrospirota and Acidobacteriota exhibited a significant increase in November. Furthermore, the functional genes associated with sulfur metabolism, nitrogen fixation, and oxidative phosphorylation displayed significant temporal variations in the aeration pond, highlighting that both growth period changes and treatment processes influence the expression of functional genes within biofilms. Our findings suggest that the integration of water treatment processes in SFCWs enhances the synergistic effects between aquatic plants and microorganisms, helping to mitigate the adverse impacts of vegetation period changes and ensuring stable and efficient wastewater treatment performance.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Macieja S, Piegat A, Mizielińska M, et al (2025)

The Effect of the Ratio of Butylene Succinate and Dilinoleic Diol in Their Copolyester (PBS-DLS) on the Physicochemical Properties and Biofilm Formation.

Molecules (Basel, Switzerland), 30(6): pii:molecules30061387.

Biofilm-forming microorganisms pose a severe threat in the food and medical industries, among others. In this paper, the research materials were poly(butylene succinate-dilinoleic succinate) (PBS-DLS) copolymers with variable hard and soft segment weight ratios (90:10, 70:30, and 50:50). Polymeric films were prepared by the solvent casting method. Selected physicochemical properties and the tendency to form biofilm on the polymer surface were investigated. As the amount of DLS soft segments in the polymer matrix increased, changes in the FTIR-ATR spectra (signal intensity), surface (SEM), and phase transition (DSC) were observed. The higher the content of the DLS segment, the lower the transition temperatures and the smoother the film's surface. These factors resulted in a significant reduction in the amount of biofilm formed on the material's surface and a decrease in the metabolic activity of microorganisms present in the biofilm and SEM micrographs. The obtained PBS-DLS films have great potential in the food and medical packaging industries.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Hanif N, Miftah JA, Yanti HD, et al (2025)

Integrated Biological and Chemical Investigation of Indonesian Marine Organisms Targeting Anti-Quorum-Sensing, Anti-Biofilm, Anti-Biofouling, and Anti-Biocorrosion Activities.

Molecules (Basel, Switzerland), 30(6): pii:molecules30061202.

Microorganisms play a significant role in biofouling and biocorrosion within the maritime industry. Addressing these challenges requires an innovative and integrated approach utilizing marine natural products with beneficial properties. A comprehensive screening of 173 non-toxic EtOAc and H2O extracts derived from diverse marine organisms collected in Indonesian waters was conducted using a robust panel of assays. These included antimicrobial tests and classical biosurfactant assays (drop collapse and oil displacement), as well as anti-quorum-sensing (QS) and anti-biofilm assays. These screening efforts identified five active extracts with promising activities. Among these, EtOAc extracts of the marine tunicate Sigilina cf. signifera (0159-22e) and the marine sponge Lamellodysidea herbacea (0194-24c) demonstrated significant anti-biofouling activity against Perna indica and anti-biocorrosion performance (mpy 10.70 ± 0.70 for S. cf. signifera; 7.87 ± 0.86 for L. herbacea; 13.60 ± 1.70 for positive control Tetracorr CI-2915). Further chemical analyses of the active extracts, including LC-HR-MS/MS, MS-based molecular networking, and chemoinformatics, revealed the presence of both known and new bioactive compounds. These included tambjamines and polybrominated diphenyl ethers (PBDEs), which are likely contributors to the observed bioactivities. Subsequent investigations uncovered new anti-QS and anti-biofilm properties in synthetic and natural PBDEs 1-12 previously derived from L. herbacea. Among these, 8 exhibited the most potent anti-QS activity, with an IC50 value of 15 µM, while 4 significantly reduced biofilm formation at a concentration of 1 µM. This study highlights the potential of marine-derived compounds in addressing biofouling and biocorrosion challenges in a sustainable and effective manner.

RevDate: 2025-03-27
CmpDate: 2025-03-27

Singh AA, Khan F, M Song (2025)

Biofilm-Associated Amyloid Proteins Linked with the Progression of Neurodegenerative Diseases.

International journal of molecular sciences, 26(6): pii:ijms26062695.

Biofilm-associated amyloid proteins have emerged as significant contributors to the progression of neurodegenerative diseases, representing a complex intersection of microorganisms and human health. The cross-beta sheet structure characteristic of amyloids produced by gut-colonizing bacteria remains intact, crucial for the resilience of biofilms. These amyloids exacerbate neurodegenerative disorders such as Alzheimer's and Parkinson's by cross-seeding human amyloidogenic proteins like amyloid-beta and α-synuclein, accelerating their misfolding and aggregation. Despite molecular chaperones and heat shock proteins maintaining protein homeostasis, bacterial amyloids can overwhelm them, worsening neuronal damage. Genetic variations in chaperone genes further influence amyloidogenesis and neurodegeneration. Persistent bacterial infections and inflammation compromise the blood-brain barrier, allowing inflammatory molecules and amyloids to enter the brain, perpetuating the cycle of neurodegeneration. The gut-brain axis underscores the impact of dysbiosis and gut microbiota on brain function, potentially contributing to neurodegeneration. The enhancement of biofilm resilience and antibiotic resistance by functional amyloid fibrils complicates the treatment landscape. The interplay among chaperone systems, microbial amyloids, and neurodegenerative diseases underscores the urgent need for advanced treatment strategies targeting these pathways to attenuate disease progression. Understanding the processes that relate biofilm-associated amyloids to the onset of neurological disorders is critical for diagnosing and developing novel treatment strategies.

RevDate: 2025-03-26

Liu K, Liu Y, Wang Q, et al (2025)

PaAP-Activatable NIR Probe for Diagnosing, Imaging, and Discovering Small-Molecule Therapeutics against Implant-Associated Biofilm Infections.

Journal of medicinal chemistry [Epub ahead of print].

Biofilm formation on medical implants causes implant-associated infections (IAIs), leading to high morbidity and mortality. Developing molecular tools for precise biofilm detection, along with novel strategies and agents to target biofilm-related IAIs, is crucial for improving treatment options and patient outcomes. Pseudomonas aeruginosa aminopeptidase (PaAP), a key biofilm-associated virulence factor, is a promising target for combating infections. Here, we developed a PaAP-activatable near-infrared (NIR) fluorescent probe, Hcy-NEO-Leu, for real-time, specific, and sensitive detection of PaAP activity. This probe enables noninvasive imaging of the P. aeruginosa biofilm in vitro and in vivo. The probe also identified LY-58, a lycorine derivative that disrupts biofilm formation without affecting bacterial growth or mammalian cell viability, enhancing tobramycin penetration and overcoming antibiotic resistance. This study introduces LY-58 as a promising adjunctive therapy. In conclusion, the PaAP-activatable NIR imaging probe, combined with LY-58, offers innovative tools for the early diagnosis and effective treatment of IAIs.

RevDate: 2025-03-26
CmpDate: 2025-03-26

Huang L, Zhang M, Luo X, et al (2025)

Sublethal Curcumin Exposure Induces Global Gene Expression and Biofilm-Related Phenotypic Changes in Vibrio parahaemolyticus.

Current microbiology, 82(5):212.

Vibrio parahaemolyticus, a foodborne pathogen found in marine environments, is susceptible to the antimicrobial effects of curcumin-a lipophilic polyphenolic pigment with diverse biological activities. While sublethal doses of curcumin inhibit behaviors of V. parahaemolyticus, the underlying molecular mechanisms remain poorly characterized. In this study, we aimed to investigate the impact of sublethal doses of curcumin on gene expression and key bacterial processes in V. parahaemolyticus. RNA sequencing (RNA-seq) revealed that sublethal curcumin concentrations significantly suppressed bacterial growth and altered the expression of 788 genes. These differentially expressed genes (DEGs) were associated with critical pathways, including upregulated systems such as polar flagellum, type IV pili, and type VI secretion systems (T6SS1 and T6SS2), as well as downregulated systems such as lateral flagella, exopolysaccharides (EPS), and type III secretion systems (T3SS1 and T3SS2). Notably, most DEGs involved in cyclic di-GMP (c-di-GMP) metabolism were downregulated, while putative porin-related genes were upregulated. Additionally, sublethal curcumin significantly inhibited biofilm formation and swimming motility but enhanced c-di-GMP production in V. parahaemolyticus. This study provides valuable insights into how V. parahaemolyticus adjusts its gene expression in response to sublethal levels of curcumin.

RevDate: 2025-03-26

Shang Q, Li L, Zhang Y, et al (2025)

Bio-Refinery of Organics into Value-Added Biopolymers: Exploring the Effects of Hydraulic Retention Time and Organic Loading Rate on Biopolymer Harvesting from a Biofilm-Based Process.

Toxics, 13(3): pii:toxics13030183.

This study aimed to examine the impacts of hydraulic retention time (HRT) and organic loading rate (OLR) on the alginate-like exopolymers' (ALEs) recovery potential from a biofilm-based process. A lab-scale moving bed biofilm reactor (MBBR) was operated under different HRT (12.0, 6.0, and 2.0 h) and OLR (1.0, 2.0, and 6.0 kg COD/m[3]/d) conditions. The results demonstrated that the reduction in HRT and increase in OLR had remarkable effects on enhancing ALE production and improving its properties, which resulted in the ALE yield increasing from 177.8 to 221.5 mg/g VSS, with the protein content rising from 399.3 to 494.3 mg/g ALE and the enhanced alginate purity by 39.8%, corresponding to the TOC concentration increasing from 108.3 to 157.0 mg/g ALE. Meanwhile, to illustrate different ALE recovery potentials, microbial community compositions of the MBBR at various operational conditions were also assessed. The results showed that a higher relative abundance of EPS producers (29.86%) was observed in the MBBR with an HRT of 2.0 h than that of 12.0 h and 6.0 h, revealing its higher ALE recovery potential. This study yields crucial results in terms of resource recovery for wastewater reclamation by providing an effective approach to directionally cultivating ALEs.

RevDate: 2025-03-27

Gerges BZ, Rosenblatt J, Truong YL, et al (2025)

The Antifungal Activity of a Polygalacturonic and Caprylic Acid Ointment in an In Vitro, Three-Dimensional Wound Biofilm Model.

Journal of fungi (Basel, Switzerland), 11(3):.

Candida colonization and biofilms are significant contributors to impaired wound healing. Consequently, improved treatments are needed to eradicate Candida biofilms in wounds. Wounds present complex biofilm extracellular matrix environments, with microbial cells frequently enmeshed in matrices comprising wound exudate macromolecular gels. We evaluated the ability of a polygalacturonic and caprylic acid (PG + CAP) ointment to eradicate Candida albicans, C. parapsilosis, C. glabrata, C. tropicalis, and C. auris biofilms in a fibrin gel wound biofilm model of the complex wound biofilm environment. Hypochlorous acid (HOCl) is a disinfecting antimicrobial agent that is widely used as wound irrigant, and this was used as a comparator. A single treatment with PG + CAP reduced the number of viable organisms in the C. albicans and C. glabrata biofilms by over 5 log10, in the C. parapsilosis and C. auris biofilms by over 4 log10, and in the C. tropicalis biofilm by 3.85 log10. PG + CAP was superior (p < 0.01) to HOCl in eradicating all Candida species biofilms, except for C. auris, for which both treatments fully eradicated all viable organisms. The use of HOCl in Candida-colonized wounds should include consideration of the extracellular matrix load in the wound bed. PG + CAP warrants further study in wounds compromised by Candida biofilms.

RevDate: 2025-03-26

Mugni SL, Ambrosis N, O Toole GA, et al (2025)

Interplay of virulence factors and signaling molecules: albumin and calcium-mediated biofilm regulation in Bordetella bronchiseptica.

Journal of bacteriology [Epub ahead of print].

Bordetella bronchiseptica, a respiratory pathogen capable of infecting various mammals, including humans, is associated with chronic infections. B. bronchiseptica can form biofilm-like structures in vivo, providing tolerance against environmental stresses. Recent studies have highlighted the role of cyclic diguanylate monophosphate (c-di-GMP) in this process in vitro: elevated c-di-GMP levels stimulate biofilm formation, whereas phosphodiesterase (PDE) activation reduces biofilms. Respiratory secretions, which contain albumin and calcium at higher concentrations than standard growth media, promote an increase in the amount and extracellular localization of the adenylate cyclase toxin (ACT), an important virulence factor of Bordetella spp. Secreted ACT, present in the extracellular medium or attached to the outer membrane, inhibits biofilm formation. Based on these observations, we hypothesized that serum albumin and calcium together inhibit biofilm formation and explored the potential role of c-di-GMP in this process. Our findings suggest that serum albumin and calcium inhibit B. bronchiseptica biofilm formation through two potentially independent mechanisms: one involving ACT secretion and another promoting c-di-GMP degradation. In the presence of albumin and calcium, intracellular levels of c-di-GMP were reduced, and specific PDEs appear to be involved in this process. In addition, albumin and calcium stimulated the secretion of the adhesin BrtA. This study contributes to the understanding of the mechanisms governing B. bronchiseptica biofilm formation and its modulation by host factors.IMPORTANCEBordetella bronchiseptica, a respiratory pathogen capable of infecting various mammals, forms biofilms that enhance its ability to withstand environmental stresses. This study reveals that host-derived factors, specifically serum albumin and calcium, inhibit biofilm formation through two independent mechanisms: increasing adenylate cyclase toxin secretion and promoting the degradation of cyclic diguanylate monophosphate (c-di-GMP), a key biofilm regulator. These findings provide insights into how host conditions influence B. bronchiseptica biofilm dynamics, shedding light on the complex interactions between pathogen and host that contribute to infection persistence. Understanding these mechanisms may inform strategies to mitigate chronic infections caused by B. bronchiseptica.

RevDate: 2025-03-26

Kim M-J, Zarnowski R, Jones R, et al (2025)

Vesicle inhibition reduces Candida biofilm resistance.

Antimicrobial agents and chemotherapy [Epub ahead of print].

Candida biofilm matrix components are delivered to the extracellular space by vesicles where they deposit and confer biofilm-associated drug resistance. Here, we present evidence that drugs designed to inhibit mammalian exosome production exhibit similar effects on C. albicans extracellular vesicles, ultimately eliminating biofilm matrix assembly. We find that vesicle reduction renders biofilm communities susceptible to the antifungal fluconazole. Our findings argue that vesicle trafficking pathways represent a promising target to optimize for recalcitrant fungal biofilms.

RevDate: 2025-03-26

Lavoie T, Daffinee KE, Vicent ML, et al (2025)

Staphylococcus biofilm dynamics and antibiotic resistance: insights into biofilm stages, zeta potential dynamics, and antibiotic susceptibility.

Microbiology spectrum [Epub ahead of print].

Staphylococcus spp. infections often involve biofilms, but standard antibiotic minimum inhibitory concentration (MIC) testing used to determine treatment evaluates planktonic bacterial growth only and does not account for biofilm presence, strength, or growth stage. To aid in determining a cost-effective method to solve this issue, we built upon in vitro methods initially published by Stepanovic et al. used to determine weak and strong biofilm formations. First, we determined 115 unique S. aureus isolate biofilms at 2, 4, 6, 8, 16, and 24 h to classify the hourly stages of biofilm development based on statistically significant final growth results (P < 0.001): stages one (0-6 h), two (6-16 h), three (16-24 h), and four (>24 h). Next, to further evaluate in vitro biofilm strength, electrostatic differences were measured through zeta (ζ)-potential for strong and weak biofilm producers at early and late stage-formed biofilms. The early stages of weak biofilm formers had a greater negative electrostatic charge when compared to strong biofilm formers. Meanwhile, strong biofilm formers began early stages with less negative charges before increasing the negative electrostatic charge by stage-four biofilm. At all time points, weak biofilm-forming isolate mean ζ-potentials were significantly more negative than strong biofilm formers (P = ≤0.04). Finally, to elucidate minimum eradication concentrations for biofilms, we treated stage-four biofilms with progressively higher concentrations of either daptomycin, vancomycin, or levofloxacin. Daptomycin was the only antibiotic to achieve ≥75% reduction in biofilm viability, seen at 32-256 μg/mL (64-512× MIC), and significantly reduced residual biofilm across all strong and weak biofilms. Biofilm findings showed an unexpected initial biofilm decrease in response to lower concentrations of antibiotics, followed by an increase in biofilm biomass at higher antibiotic concentrations. While higher antibiotic concentrations can be used to overcome bacterial resistance and eliminate infections, our results suggest that antimicrobial resistance is observed, regardless of bacterial biofilm strength, and that there may be an optimal treatment concentration window for achieving maximum kill. Our data add to the increasing evidence of biofilms' role in recurrent infections and the importance of antibiotic concentration.IMPORTANCEThis work is significant, as it addresses a critical gap in standard antibiotic testing by focusing on the unique characteristics of biofilm-forming Staphylococcus aureus infections, which are major contributors to recurrent and chronic infections. Unlike traditional MIC testing that evaluates planktonic bacteria, this study emphasizes the importance of biofilm presence, growth stages, and electrostatic properties in determining treatment strategies. By classifying biofilm development into distinct stages in an easily reproducible assay and measuring the biofilm zeta-potential for key differences and overall biofilm response to multiple standard antibiotic concentrations, this research provides valuable insights for the future of biofilm in vitro work. Furthermore, it highlights the efficacy of daptomycin in eradicating biofilm while identifying possibilities of optimal antibiotic concentration windows, a critical consideration for mitigating resistance and achieving effective infection control. These findings underscore the necessity of tailoring treatment to biofilm-specific dynamics, offering a path toward more effective therapeutic approaches for biofilm-associated infections.

RevDate: 2025-03-26

Brandt TJ, Skaggs H, Hundley T, et al (2025)

Burkholderia cenocepacia-mediated inhibition of Staphylococcus aureus growth and biofilm formation.

Journal of bacteriology [Epub ahead of print].

Staphylococcus aureus asymptomatically colonizes the nasal cavity and pharynx of up to 60% of the human population and, as an opportunistic pathogen, can breach its normal habitat, resulting in life-threatening infections. S. aureus infections are of additional concern for populations with impaired immune function such as those with cystic fibrosis (CF) or chronic granulomatous disease. Multi-drug resistance is increasingly common in S. aureus infections, creating an urgent need for new antimicrobials or compounds that improve efficacy of currently available antibiotics. S. aureus biofilms, such as those found in the lungs of people with CF and in soft tissue infections, are notoriously recalcitrant to antimicrobial treatment due to the characteristic metabolic differences associated with a sessile mode of growth. In this work, we show that another CF pathogen, Burkholderia cenocepacia, produces one or more secreted compounds that can prevent S. aureus biofilm formation and inhibit existing S. aureus biofilms. The B. cenocepacia-mediated antagonistic activity is restricted to S. aureus species and perhaps some other staphylococci; however, this inhibition does not necessarily extend to other Gram-positive species. This inhibitory activity is due to death of S. aureus through a contact-independent mechanism, potentially mediated through the siderophore pyochelin and perhaps additional compounds. This works paves the way to better understanding of interactions between these two bacterial pathogens.IMPORTANCEStaphylococcus aureus is a major nosocomial pathogen responsible for infecting thousands of people each year. Some strains are becoming increasingly resistant to antimicrobials, and consequently new treatments must be sought. This paper describes the characterization of one or more compounds capable of inhibiting S. aureus biofilm formation and may potentially lead to development of a new therapeutic.

RevDate: 2025-03-27

Hernández-Eligio A, Vega-Alvarado L, Liu X, et al (2025)

The role of CsrA in controls the extracellular electron transfer and biofilm production in Geobacter sulfurreducens.

Frontiers in microbiology, 16:1534446.

CsrA is a post-transcriptional regulator that controls biofilm formation, virulence, carbon metabolism, and motility, among other phenotypes in bacteria. CsrA has been extensively studied in γ-proteobacteria and firmicutes, However the cellular processes controlled for regulation in δ-proteobacteria remain unknown. In this work, we constructed and characterized the ΔcsrA mutant strain in Geobacter sulfurreducens to determine the involvement of the CsrA protein in the regulation of biofilm and extracellular electron transfer. The ΔcsrA mutant strain shows higher rates of insoluble Fe(III) reduction than the wild type using acetate as electron donor and the growth with fumarate and soluble (Fe(III)) was similar to wild type. Biofilm quantification and characterization by confocal laser scanning microscopy, showed that the ΔcsrA mutant produces up to twice as much biofilm as the wild type strain and more than 95% viable cells. Transcriptome analysis by RNA-seq showed that in ΔcsrA biofilms developed on an inert support, differentially expressed 244 genes (103 upregulated and 141 downregulated), including those related to extracellular electron transfer, exopolysaccharide synthesis, c-di-GMP synthesis and degradation. To validate the transcriptome data, RT-qPCR confirmed the differential expression of several selected genes in the ΔcsrA strain. Also, current production in microbial fuel cells was performed and the ΔcsrA strain produced 45-50% more current than the wild type. To identify the genes that changed expression in the ΔcsrA strain in the graphite electrodes in an MFC, a transcriptome analysis was performed 181 genes changed their expression in the ΔcsrA biofilms, of which 113 genes were differentially expressed only in MFC and 68 genes changed their expression as well as the transcriptome of biofilms grown on glass. In silico analysis of the 5'-UTR regions revealed that 76 genes that changed expression in the RNA-seq analysis have a consensus sequence for CsrA binding. To our knowledge this is the first report describing the involvement of CsrA in the regulation of extracellular electron transfer and biofilm in a member of the δ-proteobacteria.

RevDate: 2025-03-27
CmpDate: 2025-03-26

Ma N, Yang W, Chen B, et al (2025)

Exploration of the primary antibiofilm substance and mechanism employed by Lactobacillus salivarius ATCC 11741 to inhibit biofilm of Streptococcus mutans.

Frontiers in cellular and infection microbiology, 15:1535539.

INTRODUCTION: Lactobacillus salivarius serves as a probiotic potentially capable of preventing dental caries both in vitro and in vivo. This study focused on understanding the key antibiofilm agents and the mechanisms of action of the Lactobacilli supernatant against Streptococcus mutans.

METHODS: Streptococcus mutans biofilm was constructed and the cell-free supernatant of Lactobacillus salivarius was added. After the biofilm was collected, RNA-seq and qRT-PCR were then performed to get gene information. The influence of temperature, pH and other factors on the supernatant were measured and non-targeted metabolome analysis was performed to analyze the effective components.

RESULTS: The findings indicated that the supernatant derived from Lactobacillus salivarius could inhibit the biofilm formation of Streptococcus mutans at different times. Through transcriptome analysis, we discovered that the cell-free supernatant reduced biofilm formation, by suppressing phosphoenolpyruvate-dependent phosphotransferase systems along with two ATP-binding cassette transporters, rather than directly affecting the genes that code for glucosyltransferases; additionally, the supernatant was observed to diminish the expression of genes linked to two-component systems, polyketides/non-ribosomal peptides, acid stress response, quorum sensing, and exopolysaccharide formation. Non-targeted LC-MS/MS analysis was employed to discover a variety of potential active compounds present in the cellular filtrate of Lactobacillus salivarius that hinder the growth of S. mutans, including phenyllactic acid, sorbitol, and honokiol.

DISCUSSION: In summary, our findings support the evaluation of Lactobacillus salivarius as a promising oral probiotic aimed at hindering the formation of biofilms by cariogenic pathogens and the development of dental caries.

RevDate: 2025-03-26

Yousaf A, Ullah MH, Nawaz H, et al (2025)

Correction: SERS-assisted characterization of cell biomass from biofilm-forming Acinetobacter baumannii strains using chemometric tools.

RSC advances, 15(12):9108 pii:d5ra90030a.

[This corrects the article DOI: 10.1039/D4RA06267A.].

RevDate: 2025-03-26

Barrera-Hernández JI, Pérez-Velázquez JR, Ramírez-Trinidad Á, et al (2025)

Imide-based enones: A new scaffold that inhibits biofilm formation in Gram-negative pathogens.

Bioorganic & medicinal chemistry letters, 122:130206 pii:S0960-894X(25)00115-5 [Epub ahead of print].

We prepared a series of enones containing different substituents as potential antibiofilm molecules. The design considered the structural features previously found in N-acylhomoserine lactones, but it replaced the labile furanone with different imides portions. After evaluation, some of the analogs inhibited 50 % or more the formation of the biofilm from P. aeruginosa or A. baumannii; moreover, substituents attached at the phenyl ring, the size of the enone as well as the type of imide seemed relevant for the selectivity against the tested pathogens. In the end, we performed a molecular docking study using the crystallized LasR to describe the main interactions of the ligand-receptor complex and propose a plausible mechanism of action.

RevDate: 2025-03-25

Sun Y, Farrokh Shad M, Mansell B, et al (2025)

Leveraging primary effluent- and glycerol-driven partial denitrification-anammox within a pilot-scale tertiary step-feed moving bed biofilm reactor treating high-rate activated sludge systems effluent.

Water research, 280:123505 pii:S0043-1354(25)00418-X [Epub ahead of print].

This study investigated the possibility of utilizing primary effluent (PE) carbon as an internal carbon source to drive tertiary partial denitrification-anammox (PdNA) for treating high-rate activated sludge (HRAS) system effluent, so as to offset the consumption of external carbon such as glycerol. This pilot study was conducted in a tertiary step-feed moving bed biofilm reactor (MBBR) over 478 days, using full-scale HRAS secondary effluent as the influent. Unlike most PdNA applications that rely on the expensive supplemental carbon like methanol or glycerol, this study is the first to demonstrate that PE carbon can be utilized as a naturally available carbon source within wastewater to drive PdNA. By taking advantage of this free internal carbon source to driven PdNA, 63% to 74% savings in PE carbon consumption and ∼36% offset in glycerol consumption were achieved. Additionally, glycerol-driven PdNA further reduced both supplemental carbon and aeration energy demands by 70% and 18%. Mechanistic insights from in-situ and ex-situ batch tests revealed that the PE-driven PdNA was facilitated by an anammox-driven nitrite sink, a novel observation that allowed stable PdNA performance without nitrite accumulation. Furthermore, batch tests indicated that endogenous respiration could support PdNA. These findings highlight the potential of applying PE-driven PdNA in full-scale facilities, ushering in a new era of mainstream anammox applications in wastewater treatment, as PdNA is no longer reliant on costly external carbon addition.

RevDate: 2025-03-27
CmpDate: 2025-03-25

Biyashev B, Zhusanbayeva A, Kirkimbayeva Z, et al (2025)

Surveillance of Salmonella and antimicrobial resistance in industrial poultry enterprises: biofilm-forming strains and critical control points.

Journal of medical microbiology, 74(3):.

Introduction. Salmonella contamination in the poultry industry poses substantial health risks, especially due to biofilm-forming strains that resist disinfection and antibiotic treatment. Biofilm-forming Salmonella strains are particularly challenging to control, as they adhere to surfaces in production environments, leading to persistent contamination. This study assesses the prevalence of Salmonella, examines antibiotic resistance patterns and evaluates biosecurity effectiveness at poultry farms in Kazakhstan.Hypothesis/Gap Statement. There is limited data on the prevalence and antibiotic resistance of biofilm-forming Salmonella strains in Kazakhstan's poultry industry, highlighting a need to characterize these strains to inform effective control measures.Aim. The purpose of this study was to systematically identify and characterize Salmonella strains, including biofilm-forming types, within industrial poultry enterprises in Kazakhstan.Methodology. A total of 660 samples were collected from various poultry production sites, including feed, water sources, cloacal flushes and shoe covers. Salmonella detection followed standardized protocols, and antibiotic sensitivity of identified strains was analysed to evaluate resistance patterns.Results. Salmonella was detected in 11.5% (95% CI) of the 660 samples, with the highest contamination observed in shoe covers, cloacal flushes, feed and water. This prevalence rate indicates a significant presence of the pathogen in the country's poultry production chain, falling between the higher rates seen in countries like China (22.2%) and Egypt (29.1%) and the lower rates observed in countries like Brazil (3.4%). The most prevalent strain was Salmonella gallinarum-pullorum (61.8%), followed by Salmonella typhimurium (18.4%) and Salmonella enteritidis (14.5%). Antibiotic sensitivity analysis revealed that S. gallinarum-pullorum was largely susceptible to common antibiotics, while S. typhimurium displayed considerable resistance, emphasizing the need for alternative treatments.Conclusion. The findings underscore the importance of strict sanitary and hygiene standards throughout poultry production, with a particular focus on managing biofilm-forming Salmonella strains. Implementing comprehensive Hazard Analysis and Critical Control Points protocols is essential to address contamination hotspots effectively. Future studies should investigate genetic mechanisms underlying biofilm formation and resistance in Salmonella strains to inform targeted interventions, ultimately improving food safety and public health outcomes.

RevDate: 2025-03-25

Varin-Simon J, Haney EF, Colin M, et al (2025)

D-enantiomeric antibiofilm peptides effective against anaerobic Cutibacterium acnes biofilm.

Microbiology spectrum [Epub ahead of print].

The emergence of antibiotic resistance, biofilm formation, and internalization by host cells contribute to a high risk of chronic infections, highlighting the necessity to develop novel therapeutic strategies. Identification of natural host defense peptides (HDPs) with promising antimicrobial and antibiofilm activities led to the development of synthetic peptides with broad-spectrum efficacy. However, few studies have examined their effect on anaerobic bacterial species. This study aimed to test the effect of synthetic HDPs on Cutibacterium acnes, an anaerobe species involved in 10% of prosthesis joint infections (PJI). A preliminary screen identified three peptides (DJK5, AB009-D, and AB101-D) with promising activity against four C. acnes strains (two of which were isolated from PJI). A bactericidal effect was observed for the three peptides with 50% of planktonic bacteria killing for AB009-D and AB101-D after only 3 hours of contact. DJK5 and AB009-D inhibited the C. acnes adhesion on plastic and titanium supports with a 2-log decrease in bacterial cells. In the presence of peptides, the morphology of C. acnes cells was altered with an increase in cell length observed, especially for one of the non-PJI-related strains. Against mature biofilms, AB101-D was the most effective with an approximate 2-log decrease in adhered CFUs, indicating the induction of bacterial dispersion or death. DJK5 also inhibited C. acnes internalization by osteoblasts, with a reduction of the internalized bacteria quantity for three strains. Overall, this study demonstrates that synthetic HDPs are effective against anaerobic bacteria and hold promise as novel therapeutic candidates to prevent or treat C. acnes PJIs.IMPORTANCEThe emergence of antibiotic tolerance highlights the necessity to develop novel therapeutic strategies with promising antimicrobial but also antibiofilm activities. In this study, we tested the effect of synthetic host defense peptides (HDPs) on Cutibacterium acnes, an anaerobic species, rarely studied, whereas involved in 10% of prosthesis joint infections (PJI). In our study, we demonstrate that the selected synthetic HDPs are effective against this anaerobic bacteria, both as a preventive treatment (effect on planktonic growth, bacterial adhesion, and biofilm formation) and against internalization of C. acnes by osteoblasts, revealing that these peptides are promising as novel therapeutic candidates to prevent or treat C. acnes PJIs.

RevDate: 2025-03-26

Horng YT, Chien CC, Dewi Panjaitan NS, et al (2025)

Sucrose reduces biofilm formation by Klebsiella pneumoniae through the PTS components ScrA and Crr.

Biofilm, 9:100269.

The presence of sucrose at concentrations of 0.5-5% can either increase bacterial biofilms (Streptococcus mutans and Escherichia coli) or have no significant effect on biofilms (Pseudomonas aeruginosa and Staphylococcus aureus). However, our study revealed that 1 % sucrose reduced the biofilm formation by Klebsiella pneumoniae STU1. To explore the role of the phosphoenolpyruvate-dependent-carbohydrate: phosphotransferase system (PTS) in regulating this process, the scrA gene, which encodes the sucrose-specific EIIBC of the PTS, was deleted in K. pneumoniae to create a scrA mutant (ΔscrA). Thereafter, we observed that the biofilm formation and type 3 fimbriae production were not affected by sucrose in the ΔscrA while sucrose reduced these processes in the wild type. Furthermore, we discovered that Crr, the glucose-specific EIIA of PTS, was the primary but not the sole EIIA of ScrA in K. pneumoniae by sucrose fermentation test. In addition, deficiency of Crr reduced the biofilm formation in K. pneumoniae. Our proposed model suggests that, through the action of Crr in the absence of sucrose, the transcription of the mrk operon, which produces type 3 fimbriae, was increased, thereby influencing biofilm formation by K. pneumoniae and bacterial number in the gut of nematode. This observation differs from the regulation of polysaccharide and biofilm by sucrose in other bacteria. Our findings extend the understanding of the effects of sucrose on biofilm formation.

RevDate: 2025-03-26

Shrestha A, Shringi S, DH Shah (2025)

Rapid serotype-independent differential detection of biofilm-positive and biofilm-negative Salmonella using Fourier transform infrared biotyping.

One health (Amsterdam, Netherlands), 20:101004.

Foodborne illnesses caused by Salmonella represent a global one health challenge, with biofilm-forming strains exhibiting enhanced public health risks due to their ability to persist due to resistance to antimicrobial agents, disinfectants, and environmental stresses. While food-safety and public health investigation primarily focus on Salmonella identification and source tracing, they often overlook the biofilm-forming capacity of isolates, limiting their predictive value for risks posed by biofilm producing Salmonella. This study assessed fourier transform infrared (FTIR) biotyping for rapid serotype-independent differentiatial detection of biofilm-positive (BFP) from biofilm-negative (BFN) Salmonella. A total of 270 Salmonella strains representing 12 common serotypes were classified using three conventional biofilm assays (congo red and coomassie brilliant blue agar test, calcofluor test, and tube test) into true BFP (n = 80), true BFN (n = 64), and uncertain (n = 59) biofilm producers. Biofilm production for each group was also assessed with a microtiter plate assay. FTIR biotyping was applied to a subset of 115 strains (61 BFP, 54 BFN). Using spectral windows of 1180-1050 cm[-1] and 1400-1200 cm[-1], FTIR biotyping accurately differentiated BFP from BFN strains with 93.4 % sensitivity, 83.3 % specificity, and 88.6 % overall accuracy. FTIR biotyping differentiated 59 strains with uncertain biofilm status into BFN (n = 45) and BFP (n = 14). FTIR biotyping provides a rapid, sensitive and specific method for detection of biofilm-forming Salmonella strains. Incorporating FTIR biotyping for biofilm detection in current Salmonella surveillance and source-tracing protocols can enhance food safety risk assessments and improve Salmonella outbreak prevention.

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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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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.

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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.

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