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Bibliography on: Biofilm

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ESP: PubMed Auto Bibliography 28 Apr 2025 at 01:38 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: 2025-04-25

Mnisi TJ, Matotoka MM, Mazimba O, et al (2025)

Bioassay-Guided Isolation of Antibacterial and Anti-Biofilm Compounds from Peltophorum africanum Sond. Stem and Mechanisms of Active Fractions Against Nosocomial Pathogens.

Journal of ethnopharmacology pii:S0378-8741(25)00560-4 [Epub ahead of print].

Peltophorum africanum is widely used in indigenous medicine to treat infections, wounds, and inflammatory conditions. This study employs a bioassay-guided approach to isolate antibacterial compounds elucidating their pharmacological mechanisms and supporting their potential as sources of anti-infective agents.

AIM OF THE STUDY: The study aimed to investigate P. africanum stem as a potential source of novel compounds for drug discovery, emphasizing its antibacterial, antibiofilm, and antioxidant properties.

MATERIALS AND METHODS: Chromatographic techniques were used to fractionate and isolate antibacterial compounds. Structural elucidation was performed using NMR and LC-MS. Antioxidant activity was assessed using the DPPH radical scavenging assay. Antibacterial activity was determined using the microbroth dilution method against Pseudomonas aeruginosa and Staphylococcus aureus. Anti-biofilm activity was evaluated using the crystal violet staining method. The antibacterial mechanism of action of the most active fraction was examined by assessing changes in INT-dehydrogenase activity and monitoring the leakage of intracellular proteins and DNA.

RESULTS: Betulinic acid-3-3,4-dihydroxybenzoate and 3-octadecanoyl stigmasterol were isolated from the hexane crude extract. LC-MS identified 13 compounds. The plant samples MIC varied from 0.31-1.25 mg/mL. Isolated compounds had noteworthy activity across all biofilm phases. The fraction exhibited the lowest number of viable cells when assessing INT-dehydrogenase activity. Additionally, it was more effective in causing the release of intracellular proteins and DNA, while also displaying superior antioxidant activity.

CONCLUSION: The ability of antioxidant and antibacterial compounds of the P. africanum stem to inhibit biofilm formation and eradication of mature biofilms holds promise for the treatment of biofilm-associated nosocomial infections.

RevDate: 2025-04-25

Ogundipe TT, T Obe (2025)

Effectiveness of sanitizers on different biofilm-forming microorganisms associated with the poultry drinking water system.

Poultry science, 104(7):105122 pii:S0032-5791(25)00361-X [Epub ahead of print].

The sanitation of the poultry drinking water system (DWS) is essential to controlling pathogens and biofilms in the DWS. Intervention approaches including several sanitizers have been developed, but there is limited information on the efficacy of some of these sanitizers. The aim of this study was to evaluate the effectiveness of peracid-based (PAB), peroxide-based (PB), and hypochlorite-based (HB) sanitizers against field-isolated Salmonella (10), E. coli (2) and Bacillus (2), along with their antibiofilm effects on six of these bacterial strains on polyvinylchloride (PVC), a common DWS pipe material. The minimum inhibitory and bactericidal concentrations (MIC and MBC) were determined using the microdilution broth method. For biofilm production, PVC rings were inoculated (5-6 Log10 CFU/mL) in buffered peptone water, incubated at 30°C for 48 h, and detached with cotton swabs for quantification. The antibiofilm effect of the sanitizers was further assessed at MIC, 2X-MIC, 4X-MIC, and water (control). Data was analyzed using ANOVA and Least squares in JMP Pro 18. The MIC and MBC of PAB for all isolates ranged from 11.36 to 28.42 ppm, PB from 15.26 to 71.21 ppm, and HB was 106.67 to 350 ppm. Bacillus licheniformis formed the most biofilm (5.39 Log10 CFU/mL) as single-species bacteria while Salmonella attached more (6.36 Log10 CFU/mL) than E. coli (5.41 Log10 CFU/mL) and Bacillus (2.08 Log10 CFU/mL) when grown together in mixed cultures. PAB and HB eliminated the biofilms of all strains tested at MIC in mixed-species cultures while PB had no significant effect. Overall, PAB demonstrated the greatest potential as a DWS sanitizer, showing superior efficacy against planktonic and biofilm cells compared to PB and HB. This research highlights the importance of targeted microbial profiling and sanitizer efficacy testing for pre-harvest pathogen control, providing valuable insights for enhancing food safety in poultry production systems.

RevDate: 2025-04-25
CmpDate: 2025-04-25

Djermoun S, Rode DKH, Jiménez-Siebert E, et al (2025)

Biofilm architecture determines the dissemination of conjugative plasmids.

Proceedings of the National Academy of Sciences of the United States of America, 122(17):e2417452122.

Plasmid conjugation is a contact-dependent horizontal gene transfer mechanism that significantly contributes to the dissemination of antibiotic resistance among bacteria. While the molecular mechanisms of conjugation have been extensively studied, our understanding of plasmid transfer dynamics within spatially structured bacterial communities and the influence of community architecture on plasmid dissemination remains limited. In this study, we use live-cell fluorescence microscopy to investigate the propagation of the broad host range RP4 conjugative plasmid in Escherichia coli populations exhibiting varying levels of spatial organization. In high-density, two-dimensional cell monolayers, direct and tight contact between donors and recipients is not only necessary but also sufficient to trigger RP4 plasmid transfer, ensuring optimal plasmid propagation. In three-dimensional mature biofilms, the emergent community architecture limits the ability of donor cells to enter regions with high cell density, which hinders the establishment of direct contacts with recipients and impedes plasmid transfer in biofilms. In contrast, microcolonies, early-stage biofilms, and biofilms with a lower surface coverage leave open access points for donor cells in regions that later emerge as high-cell-density regions in mature biofilms, which facilitates plasmid transfer. These findings reveal the crucial role of bacterial community architecture in determining the efficiency of plasmid dissemination.

RevDate: 2025-04-25
CmpDate: 2025-04-25

Romero O, Gutierrez-Gongora D, J Geddes-McAlister (2025)

Cryptococcus neoformans Biofilm Formation and Quantification.

Current protocols, 5(4):e70133.

Cryptococcus neoformans is an opportunistic fungal pathogen that heads the Fungal Priority Pathogen List published by the World Health Organization (WHO) in 2022. This pathogen is a primary cause of death for immunocompromised individuals (e.g., those with HIV/AIDS, the elderly, immunotherapy recipients), causing approximately 118,000 deaths yearly worldwide. C. neoformans relies on virulence factors that include a polysaccharide capsule, melanin, extracellular enzymes, and thermotolerance to initiate and sustain host infection. Additionally, similar to other fungal pathogens (e.g., Candida albicans), C. neoformans may develop a biofilm organization linked to more persistent cryptococcal infections. Cryptococcal biofilms are highlighted in cases of cryptococcal meningitis, in which biofilm-like structures form that are highly resistant to host immune response and to antifungal therapies. In this regard, fungal biofilm formation has become an important area of study as a means to improve our understanding of the mechanisms regulating biofilm formation and infection and to advance the discovery of antibiofilm therapeutics. To assess biofilm properties and compare across treatments, quantification and evaluation of cell viability are important. Herein, we describe a standardized method to establish a cryptococcal biofilm and quantify total biomass and cell viability. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culturing and biofilm formation Basic Protocol 2: Biofilm quantification Alternate Protocol: Biofilm viability assay.

RevDate: 2025-04-25
CmpDate: 2025-04-25

Smith E, Matthews A, Westra ER, et al (2025)

Disruption of Pseudomonas aeruginosa quorum sensing influences biofilm formation without affecting antibiotic tolerance.

Microbiology (Reading, England), 171(4):.

The opportunistic bacterial pathogen Pseudomonas aeruginosa is a leading cause of antimicrobial resistance-related deaths, and novel antimicrobial therapies are urgently required. P. aeruginosa infections are difficult to treat due to the bacterium's propensity to form biofilms, whereby cells aggregate to form a cooperative, protective structure. Autolysis, the self-killing of bacterial cells, and the bacterial cell-to-cell communication system, quorum sensing (QS), play essential roles in biofilm formation. Strains of P. aeruginosa that have lost the lasI/R QS system commonly develop in patients, and previous studies have characterized distinctive autolysis phenotypes in these strains. Yet, the underlying causes and implications of these autolysis phenotypes remain unknown. This study confirmed these autolysis phenotypes in the PA14 QS mutant strains, ΔlasI and ΔlasR, and investigated the consequences of QS loss and associated autolysis on biofilm formation and antibiotic susceptibility. QS mutants exhibited delayed biofilm formation but ultimately surpassed the wild-type (WT) in biofilm mass. However, the larger biofilm mass of the QS mutants was not reflected in higher live-cell numbers, indicating an altered biofilm structure. Nevertheless, QS mutant biofilms were not more susceptible to antibiotics than the WT. Artificial supplementation of ΔlasI with a QS signal molecule (autoinducer) restored the strain's QS system without the associated costs of QS, enabling ΔlasI to achieve higher pre-treatment and post-treatment live-cell numbers. Overall, the lack of QS functioning was not detrimental to biofilm antibiotic tolerance, though the artificial disruption of QS may reduce the advantages of QS mutants within in vivo mixed-strain populations. Much remains to be understood regarding the regulation and induction of the autolysis phenotypes observed in these strains, and future research to fully elucidate the control and consequences of autolysis may offer potential for novel antimicrobial therapies.

RevDate: 2025-04-26

Leśna M, Górna K, J Kwiatek (2025)

Managing Fear and Anxiety in Patients Undergoing Dental Hygiene Visits with Guided Biofilm Therapy: Analysis of Psychological and Physiological Differences Between Women and Men-A Conceptual and Multivariate Regression Model.

Journal of personalized medicine, 15(4):.

Background: Dental anxiety is a significant barrier to dental care, leading to avoidance behaviors and compromised oral health. This study aimed to analyze fear and anxiety during dental hygiene visits with Guided Biofilm Therapy (GBT), focusing on gender differences in psychological and physiological responses to develop a more personalized approach to dental care. Methods: A total of 247 patients participated in this study. Psychological assessments included the Modified Dental Anxiety Scale (MDAS) and the State-Trait Anxiety Inventory (STAI X2), while physiological responses were measured through heart rate monitoring before and after procedures. Multivariate regression analysis was conducted to identify predictors of anxiety levels. Results: Multivariate regression analysis identified gender, sensory sensitivity (e.g., absence of tools in the field of view), past traumatic dental experiences, and individual preferences for anxiety reduction as significant predictors of anxiety levels. Gender differences were also observed in anxiety management strategies, with women more frequently preferring the elimination of sensory triggers and direct communication with dental professionals. Conclusions: The findings highlight the importance of personalized anxiety management protocols in dentistry. Tailored communication strategies, optimized clinical environments, and individualized pre- and post-procedure care plans can enhance patient experience and treatment acceptance. Implementing such patient-centered, data-driven approaches aligns with the broader principles of precision medicine in dental care.

RevDate: 2025-04-26

Torres-Cano A, de Armentia C, Roldán A, et al (2025)

Resistance to Azoles in Candida parapsilosis Isolates from Spain Is Associated with an Impairment in Filamentation and Biofilm Formation.

Journal of fungi (Basel, Switzerland), 11(4):.

In recent years, there has been an increase in the incidence of fluconazole-non-susceptible (FNS) Candida parapsilosis. The reasons why these strains are able to colonize hospitals remain unknown. It is also unclear whether these strains exhibit resistance to the disinfectants used in hospitals, facilitating their spread. For these reasons, in this work, we aimed to investigate whether fluconazole resistance was associated with virulence traits and the resistance of these strains to common hospital disinfectants. The general conclusion of the study was that more than 95% of the FNS strains, regardless of the resistance mutation they carried, had filamentation problems, whereas around 75% of the susceptible strains formed pseudohyphae and were capable of filamentation. This 95% of the FNS strains did not form pseudohyphae, did not invade agar, and did not form biofilms, while the susceptible strains exhibited the opposite behaviour. Through microfluidics experiments, we observed that both the susceptible and FNS strains were capable of adhering to a plastic surface under dynamic conditions, but the FNS strains formed unstable aggregates that did not remain attached to the surface, confirming the filamentation defect of these strains. In the second part of the study, we observed that FNS strains are susceptible to clinical disinfectants, although they presented a slight resistance to some of them, such as chlorhexidine, compared to susceptible isolates. In this work, we address important aspects to understand the dissemination of FNS strains in clinical outbreaks.

RevDate: 2025-04-26

Mahapatra A, Panda S, Tumedei M, et al (2025)

Clinical and Microbiological Evaluation of 0.2% Tea Tree Oil Mouthwash in Prevention of Dental Biofilm-Induced Gingivitis.

Dentistry journal, 13(4):.

Background: Dental biofilm-induced gingivitis is a prevalent condition caused by dental plaque accumulation. Chlorhexidine mouthwash is a gold standard for plaque control but is associated with adverse effects such as tooth staining and altered taste. This study aimed to evaluate the clinical and antimicrobial effectiveness of 0.2% tea tree oil mouthwash as a natural alternative to 0.2% chlorhexidine mouthwash. Methods: A comparative study was conducted on 60 participants aged 18-60 years, divided into two groups: Group T (tea tree oil) and Group C (chlorhexidine), each comprising 30 participants. Clinical outcomes assessed included Plaque Index (PI), Gingival Index (GI), Bleeding on Probing (BOP), and microbiological Colony Forming Units (CFUs). Parameters were recorded at baseline, 7 days, and 28 days. Results: Group T exhibited significantly lower PI and BOP scores at 7 and 28 days compared to Group C (p < 0.05). Both groups showed comparable reductions in CFU counts, indicating similar antimicrobial efficacy. Importantly, tea tree oil had fewer adverse effects, with no reports of tooth staining or altered taste, unlike chlorhexidine. Conclusion: Tea tree oil mouthwash demonstrated equivalent or superior clinical outcomes compared to chlorhexidine, with fewer side effects. It is a viable and well-tolerated alternative for managing plaque-induced gingivitis, supporting further research into its long-term use and efficacy.

RevDate: 2025-04-25

Ma N, Cai K, Zhao J, et al (2025)

Mannosylated MOF Encapsulated in Lactobacillus Biofilm for Dual-Targeting Intervention Against Mammalian Escherichia coli Infections.

Advanced materials (Deerfield Beach, Fla.) [Epub ahead of print].

Pathogenic bacterial infections pose a major concern, especially concerning mammalian enteritis and diarrhea. Compared to conventional antibiotic intervention, metal-organic frameworks (MOFs) exhibit superior antibacterial properties and lower cytotoxicity, demonstrating great promise in the treatment of pathogen-induced diarrhea. However, the achievement of their precise targeted delivery is still a significant challenge. Herein, a novel precision nano-system with a dual-targeting approach for treating intestinal infections caused by Escherichia coli (E. coli) is designed. First, Zn-MOF was synthesized based on ZnO, which possessed enhanced elimination of planktonic bacteria and biofilms. Through mannosylation, Zn-MOF@Man specifically recognized the FimH pili of E. coli, leading to its aggregation and subsequent eradication. Second, guided by whole genome sequencing, the encapsulation of Lactobacillus biofilm exertd immunomodulatory function, overcomed challenges related to intestinal targeting, and facilitated sustained drug release. Furthermore, Zn-MOF@Man/LRB maintaind microbiota equilibrium and promoted stem cell differentiation and barrier stability, ensuring consistent anti-diarrheal and anti-inflammatory efficacy in mice, piglets, and humans. This approach represents a novel dual-targeting antimicrobial strategy, combining probiotic biofilms and E. coli-oriented delivery, advancing safe and effective treatment that restores intestinal homeostasis for potential applications in both human medicine and animal husbandry.

RevDate: 2025-04-25
CmpDate: 2025-04-25

Gürpinar Tosun Ö, Ö Köseoğlu Eser (2025)

[Antibiotic Susceptibility Profile and Biofilm Formation in Sequential Chronic Pseudomonas aeruginosa Isolates from Pediatric Patients with Cystic Fibrosis].

Mikrobiyoloji bulteni, 59(2):145-157.

Kistik fibrozis (KF), solunum yollarında yoğun mukus birikimi nedeniyle kronik enfeksiyonlara yol açan genetik bir hastalıktır. Pseudomonas aeruginosa, KF hastalarında sık rastlanan ve uzun süreli enfeksiyonlara ve kolonizasyona neden olan önemli bir patojendir. Bu çalışma, KF çocuk hastalarının solunum yolu örneklerinden ardışık olarak elde edilen P.aeruginosa izolatlarının antibiyotik duyarlılık profillerinin ve biyofilm oluşturma yeteneklerinin karşılaştırılmasını amaçlamıştır. Hacettepe Üniversitesi İhsan Doğramacı Çocuk Hastanesi KF Ünitesinde 2021-2023 yılları arasında prospektif olarak takip edilen KF hastalarından (n= 80) alınan solunum yolu örneklerinde üreyen ardışık kronik P.aeruginosa izolatları incelenmiştir. Bakteri tür tanımlaması MALDI-TOF MS ile yapılmış ve konvansiyonel yöntemlerle doğrulanmıştır. Antibiyotik duyarlılık testleri EUCAST önerileri doğrultusunda sıvı mikrodilüsyon ve gradiyent test yöntemleriyle gerçekleştirilmiştir. Antibiyotik direnç genleri (blaVIM, blaIMP, blaNDM, blaKPC) polimeraz zincir reaksiyonu yöntemiyle incelenmiştir. Biyofilm oluşumu, kristal viyole mikrotitrasyon plak yöntemiyle değerlendirilmiştir. Kistik fibrozis hastalarında eşlik eden en sık sistemik bulgu ekzokrin pankreas yetmezliği (n= 58) ve bronşektazi (n= 44) olarak saptanmıştır. P.aeruginosa dışında 56 hastada başka bir etkenin daha ürediği [metisiline duyarlı Staphylococcus aureus (n= 46), metisiline dirençli S.aureus (n= 31), Acinetobacter spp. (n= 2) ve tüberküloz dışı mikobakteri (n= 2)] saptanmıştır. Bu çalışmada, izolatların antibiyotik direnci seftazidime en yüksek (%3.75), kolistine en düşük (%1.25) bulunmuştur. Tobramisin, meropenem ve levofloksasine direnç %2.5 olarak saptanırken, siprofloksasine direnç tespit edilmemiştir. Antibiyotik direnç genleri açısından en sık saptanan gen blaVIM olup ilk izolatlarda %12.5, sonraki izolatlarda ise %10 oranında belirlenmiştir. Çalışmaya dahil edilen izolatların hiçbrisinde blaKPC, blaIMP ve blaNDM direnç genleri saptanmamıştır. Biyofilm oluşumu değerlendirildiğinde, ilk izolatların %77.5'inde, sonraki ardışık 80 izolatın 59 (%73.7)'unda kantitatif olarak biyofilm oluşumu gösterilmiştir. İzolatların 11 (%18.6)'inin güçlü pozitif, 33 (%55.9)'ünün orta pozitif ve 15 (%25.4)'inin zayıf pozitif biyofilm oluşturduğu saptanmıştır. Sonuç olarak, P.aeruginosa'nın KF hastalarında yüksek biyofilm oluşturma kapasitesine sahip olduğu belirlenirken antibiyotik tedavisinin mikroorganizmanın eradikasyonunda etkin rol oynamadığı saptanmıştır. Bu çalışma, ardışık izolatların biyofilm yapımı ve antibiyotik direnç paternlerinde anlamlı değişiklikler göstermediğini ortaya koymuştur. Benzer antibiyotik duyarlılık ve biyofilm yapımı gösteren ardışık P.aeruginosa izolatlarında bakterinin yok edilmesi için antibiyofilm duyarlılık testlerinin yapılması ve yeni antibiyofilm tedavi stratejilerinin geliştirilmesi önem arz etmektedir.

RevDate: 2025-04-26

Rupa N, Donthineni PR, Basu S, et al (2025)

The burden of antimicrobial resistance in biofilm forming Staphylococcus spp. from Vernal Keratoconjunctivitis patients eyes.

Biofilm, 9:100278.

Vernal keratoconjunctivitis (VKC) is a chronic allergic ocular surface disease with seasonal recurrences and severe forms showing vision threatening complications. The purpose of the study is to understand the prevalence and diversity of biofilm-forming bacteria and antimicrobial resistance in VKC compared to healthy individuals (HC). For this, conjunctival swab samples were collected from VKC (n = 26) and HC (n = 23), of which culture positive samples were 77 % and 78.26 % respectively. The 16S rRNA gene sequencing revealed a significant increase in bacterial diversity in VKC compared to HC (p < 0.05), identifying 16 and 9 bacterial species, respectively. Staphylococcus epidermidis emerged as the predominant bacterium in both groups, with relative abundances of 52.8 % in HC and 30.2 % in VKC (p < 0.001). Biofilm formation was observed in 64.15 % of bacterial species in VKC and 31 % in HC (p < 0.001). Scanning electron microscopy analysis confirmed temporal biofilm formation by Staphylococcus spp. in both groups. Minimum inhibitory concentration testing showed that biofilm forming Staphylococcus spp. from VKC exhibited multidrug resistance (>2 antibiotics) more frequently than those from HC. Additionally, Staphylococcus spp. in VKC demonstrated higher resistance to fluoroquinolones compared to HC. These findings indicate a significantly greater prevalence of biofilm-forming and antimicrobial resistant Staphylococcus bacteria in VKC Patients compared with HC.

RevDate: 2025-04-25

Aththanayake AMKCB, Deeyamulla MP, Megharaj M, et al (2025)

Biofilm Formation and Detoxification of Hexavalent Chromium by Bacillus subtilis: A Sustainable Approach to Bioremediation.

Journal of basic microbiology [Epub ahead of print].

Hexavalent chromium [Cr(VI)] is a toxic environmental pollutant, primarily generated by industrial processes, posing a significant risk to biota. Effective detoxification of Cr(VI) is necessary before environmental discharge. This study focused on the Cr(VI) tolerance and detoxification potential of an isolated Bacillus subtilis strain KCBA07C10, along with the effects of Cr(VI) stress on its biofilm formation, and its potential application in bioremediation. The bacterial strain isolated from treated textile effluent, was subjected to growth studies in Cr(VI)-supplemented media with a low carbon source. Detoxification potential was assessed through Cr(VI) and total Cr removal analyses, while biofilm formation was evaluated using spectrophotometric assays and scanning electron microscopy. Results revealed that B. subtilis KCBA07C10 tolerates high Cr(VI) concentrations (> 16.0 mg/L) and achieves significant detoxification via bioreduction, removing nearly 88% of Cr(VI) even under nutrient-limited conditions. These findings highlight the strain's potential for bioremediation. Furthermore, quantitative assays demonstrated a positive correlation between Cr(VI) exposure and biofilm formation (p = 0.009, α = 0.05), suggesting an adaptive defense mechanism. This study highlights the potential of B. subtilis KCBA07C10 as an eco-friendly agent for Cr(VI) detoxification and bioremediation applications.

RevDate: 2025-04-25

Jungpraditphol I, Sutthiboonyapan P, Khamwachirapitak C, et al (2025)

Shotgun Metagenomics of Biofilm Microbiome in Oral Lichen Planus With Desquamative Gingivitis.

Oral diseases [Epub ahead of print].

INTRODUCTION: Oral lichen planus (OLP) is a chronic inflammatory condition often associated with desquamative gingivitis (DG). The oral microbiome's role in OLP and DG (OLP-DG) is gaining recognition, but prior 16S rRNA studies lacked taxonomic resolution. This study introduced shotgun metagenomic sequencing to thoroughly compare the supragingival and subgingival plaque microbiomes of individuals with and without OLP-DG.

METHODS: Twenty-seven participants (9 OLP-DG, 18 non-OLP) were recruited. Supra- and subgingival plaque samples were collected separately. Genomic DNA was analyzed using shotgun metagenomic sequencing. Microbial abundance and diversity were assessed through bioinformatic and statistical analyses.

RESULTS: We observed significant changes in the supragingival and subgingival microbiomes in OLP-DG. Supragingival plaque showed reduced Corynebacteriaceae and Porphyromonadaceae, with enrichment of an unnamed Synergistaceae genus and three unnamed species (Candidatus Saccharibacteria bacterium oral taxon 955 and 488 and GGB10852_SGB17523). Subgingival plaque revealed increased Flavobacteriaceae and Rhodocyclaceae, and reduced Actinomycetaceae. Although alpha or beta diversity was not significantly different, common commensals like Corynebacterium matruchotii and Streptococcus mitis were less abundant in OLP-DG patients.

CONCLUSION: This first-time application of metagenomic sequencing revealed a distinct microbiome in OLP-DG, characterized by novel bacterial species and reduced commensals, suggesting a potential role in OLP-DG pathogenesis, and warranting further study.

RevDate: 2025-04-25

Veiga FC, de Felicio R, Trivella DBB, et al (2025)

Lipopeptides from Antarctic Bacillus siamensis N52R1 inhibit Pseudomonas aeruginosa biofilm.

Journal of applied microbiology pii:8119399 [Epub ahead of print].

AIM: To search for active compounds produced by microorganisms isolated from the Antarctic environment, against biofilms of pathogenic bacteria Pseudomonas aeruginosa.

METHODS AND RESULTS: Seven different bacteria from Antarctic were cultivated, and their secretome (supernatants of the culture media) extracted using liquid/liquid partition, rendering 41 fractions of different polarities. Assays were performed to quantify P. aeruginosa pathogenic bacterial growth and inhibition of biofilm formation. From the tested Antarctic isolates the apolar hexane extract fraction of N52R1 strain, identified as Bacillus siamensis, showed activity against P. aeruginosa biofilm formation and was fractionated by reverse phase chromatography, corroborated by Confocal Laser Scanning Microscopy images. Applying LC-MS/MS untargeted metabolomics it is suggested that these results were obtained by the action of lipopeptide molecules, particularly plipastatin and surfactin which has no previous report of activity upon the important pathogen P. aeruginosa. In vivo toxicity assays of the antibiofilm fraction of N52R1 upon the invertebrate G. mellonella was performed, showing no toxicity at up to 200 mg/kg.

CONCLUSION: we demonstrate the relevance and diversity of compounds from Antarctic microorganisms, in order to find bioactive agents against P. aeruginosa biofilm formation.

RevDate: 2025-04-24
CmpDate: 2025-04-25

Huynh U, King J, ML Zastrow (2025)

Calcium modulates growth and biofilm formation of Lactobacillus acidophilus ATCC 4356 and Lactiplantibacillus plantarum ATCC 14917.

Scientific reports, 15(1):14246.

Lactobacillaceae are a large, diverse family of Gram-positive lactic acid-producing bacteria. As gut microbiota residents in many mammals, these bacteria are beneficial for health and frequently used as probiotics. Lactobacillaceae abundance in the gastrointestinal tract has been correlated with gastrointestinal pathologies and infection. Microbiota residents must compete for nutrients, including essential metal ions like calcium, zinc, and iron. Recent animal and human studies have revealed that dietary calcium can positively influence the diversity of the gut microbiota and abundance of intestinal Lactobacillaceae species, but the underlying molecular mechanisms remain poorly understood. Here, we investigated the impacts of calcium on the growth and biofilm formation of two distinct Lactobacillaceae species found in the gut microbiota, Lactobacillus acidophilus ATCC 4356 and Lactiplantibacillus plantarum ATCC 14917. We found that calcium ions differentially affect both growth and biofilm formation of these species. In general, calcium supplementation promotes the growth of both species, albeit with some variations in the extent to which different growth parameters were impacted. Calcium ions strongly induce biofilm formation of L. acidophilus ATCC 4356 but not L. plantarum ATCC 14917. Based on bioinformatic analyses and experimental chelator studies, we hypothesize that surface proteins specific to L. acidophilus ATCC 4356, like S-layer proteins, are responsible for Ca[2+]-induced biofilm formation. The ability of bacteria to form biofilms has been linked with their ability to colonize in the gut microbiota. This work shows how metal ions like Ca[2+] may be important not just as nutrients for bacteria growth, but also for their ability to facilitate cell-cell interactions and possibly colonization in the gut microbiota.

RevDate: 2025-04-24
CmpDate: 2025-04-25

Moon J, Seo K, JS Kwon (2025)

Novel two-stage expansion of Streptococcus mutans biofilm supports EPS-targeted prevention strategies for early childhood caries.

NPJ biofilms and microbiomes, 11(1):65.

Early childhood caries (ECC) affects nearly half of preschool children worldwide and characterized by rapid progression across multiple teeth. While Streptococcus mutans (S. mutans) is a keystone species in dental caries, its process for rapid biofilm expansion remains unclear. Using an air-solid interface model simulating the oral environment, we uncovered a novel expansion for S. mutans biofilms. Our findings reveal that S. mutans employs a distinct two-step expansion strategy. Through osmotic pressure, extracellular polymeric substances (EPS) spread and transport bacterial clusters to new sites. Subsequently, the hydroxyapatite surface enables new colony formation. Hydroxyapatite's acid-neutralization properties appear critical for bacterial growth and colonization. Despite successful EPS spreading, environments without hydroxyapatite failed to support new colony formation. These results reveal the unique pattern of rapid ECC progression in sugar-rich environments and establish EPS as a promising therapeutic target, advancing understanding of cariogenic biofilm behavior and preventative strategies for ECC prevention.

RevDate: 2025-04-24

Wang J, Pan Y, Wen X, et al (2025)

Rapid start-up of nitrogen and organic matter removal in sequencing batch biofilm reactors treating hypersaline mustard tuber wastewater with autochthonous microorganisms.

Journal of environmental management, 383:125490 pii:S0301-4797(25)01466-5 [Epub ahead of print].

The treatment of hypersaline industrial wastewater (≥50 g NaCl L[-1]) faces persistent challenges in start-up and nitrogen removal efficiency due to microbial inhibition under extreme salinity. However, leveraging native microbial consortia for rapid system establishment remains underexplored. This study proposed a rapid-start strategy for sequencing batch biofilm reactors (SBBRs) treating hypersaline mustard tuber wastewater (MTWW) through in-situ enrichment of autochthonous microorganisms in MTWW. Five SBBRs, each with distinct inoculation (municipal sludge vs. autochthonous microorganisms) and salinity-increase strategies (direct vs. gradual increase), were systematically compared. Systems acclimated with autochthonous microorganisms achieved start-up within 30 days (Phase Ⅰ:0-30 g NaCl L[-1] and Phase Ⅱ: 30-70 g NaCl L[-1]), with COD and TN removal efficiencies of 82.40 %-92.85 % and 85.72 %-94.68 %, respectively. Notably, rapid-start systems maintained comparable TN and COD removal to gradual acclimation (p > 0.05) despite transient nitrification instability during dissolved oxygen fluctuations (recovered within 5∼6 cycles). The rapid-start reactors demonstrated greater ammonia oxidation activity, driven by the dominance of ammonia-oxidizing archaea (AOA) over bacteria (AOB). Rapid salinity increases selectively enriched halophilic functional bacteria, such as Halomonas, Nitratireductor, Arcobacter, and Phaeodactylibacter, supporting anoxic/aerobic and sulfur-driven autotrophic denitrification processes. Most of the functional microorganisms across all reactors originated directly from the MTWW, confirming the indispensability of autochthonous inoculum. Our findings demonstrate that autochthonous microorganisms in hypersaline MTWW can be directly engineered for rapid system establishment, bypassing lengthy acclimation. This strategy reduces start-up costs and provides a scalable solution for industries requiring immediate hypersaline wastewater treatment capacity.

RevDate: 2025-04-25

Xu S, Fan B, Gao S, et al (2025)

Clinical isolation, biofilm formation, and pathogenicity analysis of different species of the Stephanoascus ciferrii complex.

Frontiers in microbiology, 16:1570952.

The Stephanoascus ciferrii complex, comprising Stephanoascus ciferrii, Candida allociferrii, and Candida mucifera, is an emerging fungal pathogen with increasing isolation rates and antifungal resistance. However, detailed information about clinical isolation rates and pathogenicity comparisons among the three species are lacking. In order to fill in this information gap, this study aimed to investigate and compare the clinical isolation rates and pathogenicity of the three species. Twenty-seven S. ciferrii complex strains isolated from the secretion specimens of patients admitted to Nanjing Drum Tower Hospital between 2012 and 2023 were included. According to the results of ITS sequencing, there were 15 strains of S. ciferrii, 7 strains of C. allociferrii, and 5 strains of C. mucifera. Antifungal susceptibility testing demonstrated that the S. ciferrii complex exhibited high MICs against azole antifungal agents, particularly fluconazole, while it showed lower MICs against echinocandins. S. ciferrii displayed higher MICs against caspofungin than C. allociferrii (P < 0.05). The results of biofilm quantification using crystal violet staining indicated C. allociferrii exhibited stronger biofilm-forming ability than S. ciferrii in RPMI-1640 medium (P < 0.05), but there was no significant difference between C. allociferrii and C. mucifera or between S. ciferrii and C. mucifera. The results were similar with the metabolic activity by using XTT assay. The G. mellonella larvae infection experiments revealed that the survival rates of larvae infected by strains of the S. ciferrii complex were 60%, 50%, and 48% at 24 h, 48 h, and 72 h, respectively. Furthermore, the G. mellonella larvae lethality caused by C. allociferrii and C. mucifera were significantly higher than that caused by S. ciferrii (P < 0.001). This study is the first to describe and compare the pathogenicity and biofilm formation ability of the three species of S. ciferrii complex in the clinical context. Our research reveals the high prevalence of S. ciferrii in the complex and elucidates the correlation between fungal drug resistance, biofilm formation, and virulence, thus providing essential empirical evidence for further study of the clinical pathogenic characteristics of each species in the complex and treatment strategies.

RevDate: 2025-04-23

Ali HR, Valdivia C, D Negus (2025)

Bacteriophage-embedded and coated alginate layers inhibit biofilm formation by clinical strains of Klebsiella pneumoniae.

Journal of applied microbiology pii:8118814 [Epub ahead of print].

AIMS: This study aimed to determine the antibiofilm properties of Klebsiella pneumoniae phages previously isolated from Thai hospital sewage water. Furthermore, we aimed to develop a phage-embedded and coated alginate hydrogel, suitable as a wound dressing or surface coating to prevent K. pneumoniae proliferation and biofilm formation.

METHODS AND RESULTS: The biofilm forming capacity of six clinical K. pneumoniae isolates was determined by means of the crystal violet assay and four strains which exhibited strong adherence were selected for further characterisation. Two phages (vB_KpnA_GBH014 and vB_KpnM_GBH019) were found to both significantly prevent (P = <0.0005) and disrupt (P = <0.05) biofilms produced by their K. pneumoniae hosts as determined by optical density readings using the crystal violet assay. Furthermore, alginate layers embedded and coated with phages vB_KpnA_GBH014 and vB_KpnM_GBH019 produced antibiofilm surfaces. Viable counts of recovered biofilms showed that alginate hydrogels containing phage vB_KpnA_GBH014 or vB_KpnM_GBH019 were associated with significantly fewer K. pneumoniae versus no-phage controls (1.61×108 cfu ml-1 vs 1.67×104 cfu ml-1, P = <0.005 and 1.78×108 cfu ml-1 vs 6.11×102 cfu ml-1, P = <0.00005, respectively). Confocal microscopy further revealed a significant reduction in the biovolume of biofilms formed on phage embedded and coated alginate hydrogels compared to no-phage controls.

CONCLUSIONS: Phages vB_KpnA_GBH014 and vB_KpnM_GBH019 can both prevent and disrupt biofilms produced by clinical isolates of K. pneumoniae. Embedding and coating these phages into alginate produces an antibiofilm matrix which may have promise for coating medical devices or as a wound dressing.

RevDate: 2025-04-23

Highmore C, Cooper K, Parker J, et al (2025)

Real-time detection of Foodborne Pathogens and Biofilm in the food processing environment with Bactiscan, a macro-scale fluorescence device.

Journal of food protection pii:S0362-028X(25)00063-8 [Epub ahead of print].

Food safety relies on rapid detection methods and rigorous sampling of the food processing environment, and is challenged by recurrent biofilm contamination and by sub-lethally injured bacteria that can evade detection. Bactiscan is investigated as an alternative detection approach, a macro-scale and reagentless device that detects microbial contamination through activating green fluorescence of glycoproteins in the bacterial cell wall. The detection capability of Bactiscan was tested on foodborne pathogens Escherichia coli, Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus. Detection by Bactiscan was assessed using 3 independent observers viewing bacterial samples dried on stainless steel, using 3 biological repeats and 5 technical repeats. Detection by Bactiscan was possible to 1.20*10[6] colony forming units (CFU), compared to 1.36*10[4] CFU by ATP swab testing, where Bactiscan detection limits were defined by the concentration at which 50% of the samples were observed under illumination of the device. Heat-killed and chlorine stressed E. coli and S. enterica caused a 2-log reduction in detection by ATP swab tests (p≤0.05), while detection by Bactiscan was unaffected (p≥0.05). Pathogen biofilms were detectable via Bactiscan with >80% accuracy at 4 days of growth; E. coli and L. monocytogenes biofilms were visible at 2 days of growth. In situ contamination studies determined that Bactiscan can detect microbial contamination on chicken, salmon, and yoghurt samples with stronger fluorescence than a competitor UV torch. The presence of one of the pathogens on the food samples was confirmed by metagenome sequencing, determining that S. aureus was present in 7 samples out of 9 with a relative abundance of >0.5%. These data demonstrate that Bactiscan can effectively detect bacteria present in the food processing environment and can complement existing technologies to improve food industry cleaning practices and infection prevention.

RevDate: 2025-04-24

Keikhosravani P, Khodaei A, Bollen T, et al (2025)

Developing antibacterial HB43 peptide-loaded chitosan nanoparticles for biofilm treatment.

International journal of biological macromolecules, 310(Pt 2):143397 pii:S0141-8130(25)03949-2 [Epub ahead of print].

Biofilm-associated infections on medical devices are challenging to treat. Therefore, innovative treatment approaches are needed to penetrate biofilms and eliminate bacteria. With this study, we developed chitosan nanoparticles (CNPs) encapsulating the antibacterial peptide HB43 at increasing CNP/peptide ratios (from 1 to 4 % for P1-CNP, P2-CNP, and P4-CNP, respectively) using the ion gelation method. Our goal was to enhance antibacterial drug delivery inside a methicillin-resistant Staphylococcus aureus (MRSA) biofilm. Our analysis showed a direct correlation between the encapsulation efficacy of HB43 and the physical properties of the CNPs, such as size and zeta potential. P1-CNP was identified as the optimal formulation, characterized by its small size, high encapsulation efficiency, and cationic surface charge. Release studies indicated that HB43 was released in a sustained manner particularly under acidic conditions, which enhanced therapeutic efficacy. We tested the P1-CNP in culture media with pH levels of 7.4 and 5.5 to assess the pH responsiveness of the CNPs and mimic the infection environment. Both conditions showed that the HB43 loaded-CNPs effectively reduced bacterial populations in a dose-dependent manner, with up to a 99.99 % reduction in bacterial load. This study offers a promising new strategy for managing biofilm-associated infections and addressing antibiotic resistance by using CNPs loaded with HB43.

RevDate: 2025-04-23

Widyasrini DA, Annisa M, Sunarintyas S, et al (2025)

Magnesium Infusion on Dental Implants and Its Impact on Osseointegration and Biofilm Development: A Review.

European journal of dentistry [Epub ahead of print].

Dental implants have gained global popularity as a treatment option for tooth loss. The success of dental implants depends on their optimal integration into the tissues of the alveolar bone and the periodontium. However, several factors can hinder the proper osseointegration of implants, with the growth of biofilm on the implant surface and subsequent peri-implant infections being significant concerns. To overcome this challenge, researchers have explored the incorporation of antimicrobial agents onto metallic implant surfaces to mitigate biofilm growth. Ideally these agents should promote osteogenesis while exhibiting antibacterial effects. Magnesium (Mg) has emerged as a promising dual-function implant coating due to its osteogenic and antibacterial properties. Despite several studies, the precise mechanisms behind osteoinductive and antimicrobial effect of Mg is unclear, as yet. This review aims to collate and discuss the utility of Mg as a dental implant coating, its impact on the osteogenic process, potential in mitigating microbial growth, and prospects for the future. A comprehensive literature search was conducted across several databases and the findings reveal the promise of Mg as a dual-function dental implant coating material, both as a standalone agent and in combination with other materials. The antibacterial effect of Mg is likely to be due to its (1) toxicity particularly at high concentrations, (2) the production or reactive oxygen species, and (3) pH modulation, while the osteoinductive effect is due to a complex series of cellular and biochemical pathways. Despite its potential both as a standalone and composite coating, challenges such as degradation rate, leaching, and long-term stability must be addressed. Further research is needed to understand the utility of Mg as an implant coating material, particularly in relation to its antibacterial activity, osseointegration, and longevity in the oral milieu.

RevDate: 2025-04-23

Yang Z, Chen H, Zhong GH, et al (2025)

cAMP-Mediated Biofilm eDNA Transfer Facilitates the Resilience of Soil Microbiome to Agrochemical Stress.

Journal of agricultural and food chemistry [Epub ahead of print].

Soil microorganisms utilize extracellular DNA (eDNA)-based biofilms as a defense against xenobiotics. However, the specific effects and transfer pathways of eDNA under persistent agrochemical exposure remain unclear. This study examined the transfer dynamics of carbofuran-hydrolase gene pchA from Pseudomonas stutzeri PS21. During biofilm formation, pchA was released from eDNA, leading to an enrichment of beneficial microorganisms such as Acidobacteria and Elusimicrobia, which enhanced organic compound metabolism and improved soil microbiome resilience. An increase in the pchA-associated mobile genetic elements and the colocalization of pchA with other bacterial species indicated the potential horizontal gene transfer (HGT) under carbofuran exposure. Additionally, carbofuran triggered a cAMP-dependent apoptotic pathway, leading to a 59.6% increase in pchA copy number, which suggested that cAMP played a role in initiating HGT. In conclusion, the cAMP-mediated interspecific transfer of pchA could enhance microbial coadaptation to carbofuran contamination, thereby strengthening the collective defense of soil microbiome against agrochemical stress.

RevDate: 2025-04-24

Leejae S, Pelyuntha W, Goodla L, et al (2025)

Silver Nanoparticles Synthesized From Centella asiatica Extract and Asiatic Acid for Enhanced Biofilm Eradication of Streptococcus Associated With Oral Diseases.

Scientifica, 2025:4867529.

The biofilm-forming ability of Streptococcus species, particularly Streptococcus mutans, is a key factor in the pathogenesis of dental caries and periodontitis. Current treatments often exhibit limitations such as incomplete biofilm eradication and cytotoxicity to host tissues, highlighting the need for innovative and biocompatible therapeutic approaches. Therefore, this study aimed to investigate the potential of Centella asiatica ethanolic extract, its bioactive triterpenoids (asiatic acid and madecassic acid), and silver nanoparticles (AgNPs) synthesized from the extract as an alternative strategy for targeting S. mutans biofilms. The antibacterial and antibiofilm activities of the synthesized AgNPs against Streptococcus species were evaluated, alongside cytotoxicity assessments on human gingival fibroblast (HGF-1) cells using the MTT assay. The synthesized AgNPs exhibited superior antimicrobial efficacy compared to the extract, with significantly lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (62.5/125 µg/mL) against S. mutans ATCC 25175 and S. mitis ATCC 49456, highlighting their potent bactericidal activity. Moreover, the AgNPs achieved rapid biofilm disruption, reducing biofilm biomass by 76% within 12 h at 1/2 × MIC, significantly outperforming the extract and triterpenoids. Scanning electron microscopy further revealed substantial extracellular polymeric substance degradation and biofilm structural disruption upon AgNP treatment, confirming their pronounced antibiofilm efficacy. In addition, the synthesized AgNPs demonstrated favorable biocompatibility, maintaining 68% cell viability in dental fibroblast cells, suggesting an optimal balance between antimicrobial potency and cytotoxicity. The synergistic interaction between AgNPs and C. asiatica phytochemicals significantly enhanced biofilm disruption compared to nonfunctionalized AgNPs. These findings underscore the potential of C. asiatica-based AgNPs as a novel, plant-derived nanotechnological approach for managing oral infections caused by biofilm-forming Streptococcus species. This study not only contributes to the development of alternative antibiofilm strategies but also paves the way for future clinical applications in oral healthcare.

RevDate: 2025-04-24

Rafiee Z, Rezaie M, S Choi (2025)

Rapid and sensitive antimicrobial susceptibility testing of biofilm-forming bacteria using scalable paper-based organic transistors.

iScience, 28(4):112312.

A scalable, cost-effective paper-based organic field-effect transistor platform has been developed for rapid antimicrobial susceptibility testing (AST) of biofilm-forming pathogens. Traditional AST methods are costly, labor-intensive, and slow, with a lack of standardized biofilm models. This system directly tracks protons generated by biofilms, which serve as key indicators of bacterial metabolism under antibiotic exposure. A proton-sensitive PEDOT:PSS channel is employed, where metabolic proton activity de-dopes the transistor, reducing conductivity. The engineered paper substrate facilitates rapid, high-quality biofilm formation, improving assay reliability. The platform was validated on three clinically significant pathogens against frontline antibiotics, providing real-time, quantitative antibiotic efficacy profiles. Integrated with a microcontroller and machine learning algorithm, results are displayed on a liquid crystal display (LCD), classifying antibiotic concentration relative to the minimum inhibitory concentration with over 85% accuracy. This clinically translatable system offers a high-throughput, point-of-care solution for efficient infection management and antibiotic stewardship.

RevDate: 2025-04-23
CmpDate: 2025-04-23

Wu Z, Lei X, Zhang Y, et al (2025)

The membrane protein DtpT plays an important role in biofilm formation and stress resistance in foodborne Staphylococcus aureus RMSA49.

Food research international (Ottawa, Ont.), 208:116249.

Staphylococcus aureus has been a major contributor to the contamination of dairy products and preserved foods due to its capacity for biofilm formation and strong resistance to environmental stress. The membrane transport protein di-and tripeptides transporter (DtpT) is the primary transporter of di- and tripeptides in S. aureus, yet its impact on biofilm formation and stress resistance in S. aureus has not been previously reported. Our study focused on the foodborne S. aureus strain RMSA49, revealing that mutation of the dtpT resulted in diminished biofilm formation ability and reduced tolerance to environmental stress (high temperature, dryness, oxidative stress, and salt stress). These findings highlight the significance of DtpT in both biofilm formation and response to environmental stress in foodborne S. aureus. Our study represents the first report demonstrating the crucial role of DtpT in biofilm formation and environmental tolerance in S. aureus, providing new avenues for future research on this protein while also identifying potential target genes for further investigation into S. aureus tolerance mechanisms during food processing and control of biofilm formation.

RevDate: 2025-04-23
CmpDate: 2025-04-23

Lu Z, Zhang J, Li J, et al (2025)

Biofilm formation of Pseudomonas fluorescens induced by a novel diguanylate cyclase modulated c-di-GMP promotes spoilage of large yellow croaker (Larimichthys crocea).

Food research international (Ottawa, Ont.), 208:116231.

Pseudomonas as major agents cause the microbial spoilage in aerobically stored seafoods due to the strong biofilm forming ability, resulting in significant economic losses. C-di-GMP regulates the transition to biofilm states in numerous bacteria, however, its function in biofilm and spoilage of Pseudomonas fluorescens has still been scarce. Here, in a fish spoiler P. fluorescens PF07 strain, 26 proteins of diguanylate cyclase (DGC) containing a GGDEF domain were characterized, and both intracellular c-di-GMP and biofilm formation consistently decreased in the constructed 12 deletion mutants of DGC domain. Compared to wild type (WT) strain, both swimming and swarming in these mutants remarkably enhanced, while the secretion of siderophore, protease activity, and the production of total volatile basic nitrogen (TVB-N) were decreased in several mutants, indicating the different modulating effects among these DGC mutants. Furthermore, correlation analysis of these six phenotypes, PF07_04309 exhibited the most significant alteration, which was identified a novel functional DGC enzyme. Moreover, the GGAAA mutation of PF07_04309 induced the down-regulation of Psl and Alg operons and increased flagellar related gene, resulting in forming the sparser and thinner biofilms. Two mutants of 04309 induced by low c-di-GMP significantly declined the accumulation of TVB-N, thiobarbituric acid, extracellular protease activity and spoilage flavor compounds, especially methylamine and carbon disulfide, in the fillets of large yellow croaker stored at 4 °C. Thus, our results indicated that a novel DGC 04309 modulated the polysaccharide secretion, flagellar, and iron carrier by synthesis of c-di-GMP, positively regulating the spoilage potential of P. fluorescens, which expanded the original insights of DGC and c-di-GMP function on microbial food spoilage.

RevDate: 2025-04-22

Esteves Barros IL, Franco Veiga F, TI Estivalet Svidzinski (2025)

In vitro characterization of biofilm produced by Fusarium oxysporum, an onychomycosis agent.

Anais brasileiros de dermatologia pii:S0365-0596(25)00052-2 [Epub ahead of print].

RevDate: 2025-04-22

Rodrigues GWL, Del Bianco Vargas Gouveia S, Oliveira LC, et al (2025)

Comparative analysis of antimicrobial activity and oxidative damage induced by laser ablation with indocyanine green versus aPDT with methylene blue and curcumin on E. coli biofilm in root canals.

Odontology [Epub ahead of print].

Laser ablation and Antimicrobial Photodynamic Therapy (aPDT) serve as adjunctive treatments to enhance microbial reduction in endodontic root canals. This in vitro study assessed laser ablation with Indocyanine Green (ICG) compared to aPDT using Methylene Blue (MB) and Curcumin (CUR) photosensitizers for reducing E. coli biofilms and inducing oxidative damage in root canals. Methods Standardized bovine upper incisor roots (n = 100) were contaminated with E. coli for 10 days to form biofilms. Groups included ICG 0.05% activated by infrared diode laser, CUR 0.05% activated by blue LED, MB 0.01% activated by red laser, sterile saline (NC), and 2.5% sodium hypochlorite (PC). Root canal samples were collected pre- and post-treatment, plated on BHI agar for CFU/mL counting. Oxidative damage was assessed using TBARS and carbonylated protein methods. Percentage reduction data underwent two-way ANOVA and Student-Newman-Keuls test, Kruskal-Wallis, and Dunn's tests for CFU reduction, and one-way ANOVA (p < 0.05) for oxidative damage. Results No statistical differences were found among groups for E. coli reduction. All groups had higher reduction than NC and lower reduction than PC (p < 0.05). ICG and CUR showed higher oxidative damage than MB and controls in protein carbonyl analyses. In TBARS analysis, ICG exhibited the greatest oxidative damage, statistically higher than other photosensitizers, negative, and positive controls. Conclusion There was no difference between laser ablation with ICG and aPDT with CUR and MB, which were less effective in bacterial reduction than NaOCl. However, ICG-induced higher oxidative damage in Gram-negative bacteria, suggesting its potential as an adjunctive therapy in root canal procedures.

RevDate: 2025-04-22
CmpDate: 2025-04-22

Chowdhury MAH, Reem CSA, Ashrafudoulla M, et al (2025)

Role of advanced cleaning and sanitation techniques in biofilm prevention on dairy equipment.

Comprehensive reviews in food science and food safety, 24(3):e70176.

Biofilm formation on dairy equipment is a persistent challenge in the dairy industry, contributing to product contamination, equipment inefficiency, and economic losses. Traditional methods such as manual cleaning and basic chemical sanitation are discussed as foundational approaches, followed by an in-depth investigation of cutting-edge technologies, including clean-in-place systems, high-pressure cleaning, foam cleaning, ultrasonic and electrochemical cleaning, dry ice blasting, robotics, nanotechnology-based agents, enzymatic cleaners, and oxidizing agents. Enhanced sanitation techniques, such as dry steam, pulsed light, acidic and alkaline electrolyzed water, hydrogen peroxide vapor, microbubble technology, and biodegradable biocides, are highlighted for their potential to achieve superior sanitation while promoting sustainability. The effectiveness, feasibility, and limitations of these methods are evaluated, emphasizing their role in maintaining dairy equipment hygiene and reducing biofilm-associated risks. Additionally, challenges, such as equipment compatibility, cost, and regulatory compliance, are addressed, along with insights into future directions and innovations, including automation, smart cleaning systems, and green cleaning solutions. This review provides a comprehensive resource for researchers, industry professionals, and policymakers aiming to tackle biofilm formation in dairy production systems and enhance food safety, operational efficiency, and sustainability.

RevDate: 2025-04-23

Tirumala N, LR K (2025)

Bacteriological Profile of Diabetic Foot Ulcer With Special Reference to Biofilm Formation.

Cureus, 17(3):e80974.

Introduction Diabetes mellitus is a metabolic disorder characterized by abnormally high sugar levels in the blood for prolonged periods of time. The world's largest number of diabetics resides in India, making it the world's diabetic capital, with a diabetic foot ulcer (DFU) incidence of around 8-17%. Due to the polymicrobial and multidrug resistant (MDR) nature of DFUs, antimicrobial susceptibility testing is of high importance to help treat patients effectively and prevent the development of MDR bacteria. The ability to form biofilms is a significant additive to virulence of an organism that causes an able strain to be resistant to more antibiotics as compared to a free-living strain, thereby further delaying the healing of DFUs. Materials and methods This study included 74 samples collected from patients with DFUs, out of which 69 (93.24%) yielded growth on culture. Gram staining was done for the direct microscopy, isolation, and determination of organism, and the detection of biofilm formers using Congo Red Agar plates. Data were tabulated and statistically analyzed. Results Out of 74 samples collected, 69 (93.24%) yielded growth on culturing, with 5 (6.76%) cultures coming back negative. On Gram staining, 42 (56.8%) samples showed Gram-positive cocci and 53 (71.6%) showed Gram-negative bacilli. On isolating organisms from the samples, 16 (21.7%) samples had Pseudomonas aeruginosa, followed by Klebsiella pneumoniae at 13 (17.6%) and Proteus mirabilis and Escherichia coli at 11 each (14.9%), indicating a Gram-negative bacteria predominance. Of the Gram-positive bacteria isolated, Staphylococcus aureus stands at two (2.7%) and Streptococcus pyogenes at one (1.4%). The prevailing monomicrobiality could be attributed to antibiotic administration prior to sample collection. On antibiotic sensitivity of organisms tested against each antibiotic, more than 75% of tested samples were resistant to ampicillin, cefuroxime, and erythromycin, and around 70% and more of tested samples were sensitive to ertapenem, meropenem, amikacin, gentamicin, benzylpenicillin, vancomycin, and clindamycin. Out of the 69 positive cultures, 29 (42.03%) yielded biofilm formers. Pseudomonas aeruginosa was the predominant biofilm former with 10 (34.48%) of 29 of total biofilm-forming isolates, followed by E. coli and K. pneumoniae with five each (17.24%) and Proteus mirabilis with three samples (10.34%). Regarding strains forming biofilms according to bacterium species, S. aureus was predominant, with 100% (two out of two samples) of isolates forming biofilms. Staphylococcus aureus was followed by Pseudomonas aeruginosa with 62.5% (10 out of 16 samples), Acinetobacter baumannii (two out of four samples) and Enterobacter cloacae (one out of two samples) with 50% each, E. coli with 45.45% (5 out of 11 samples), and K. pneumoniae with 38.46% (5 out of 13 samples) of isolates forming biofilms. It should be noted that only two S. aureus, four A. baumannii, and two Enterobacter cloacae samples were isolated in comparison to a larger number of Gram-negative bacteria. This study has found that 100% of multidrug-resistant organisms (MDROs) are biofilm formers. Conclusion The ability to form biofilms adds immensely to the virulence and antibiotic resistance. Detection of biofilm formers is non-invasive and convenient to measure and would help provide insight into antibiotics to be administered to the patient, thereby reducing development of MDROs and reducing healing time.

RevDate: 2025-04-21

Lee EH, Kim H, Lee JH, et al (2025)

Self-Powered Oxygen Microbubble Generator for Decontamination of Anaerobic Biofilm-Fouled Bioimplants.

ACS biomaterials science & engineering [Epub ahead of print].

Biomedical devices often feature a microgap: confined, minuscule spaces that foster bacterial infiltration and biofilm formation. For instance, peri-implantitis with prevalence rates of 4.7-45% at the patient level is a major complication driven by biofilm infections, characterized by chronic inflammation and implant failure. Anaerobic biofilm residing within the microgap serves as a major source of the peri-implantitis, but tools that remove the biofilm are lacking. Therefore, this study presents a novel preventive strategy employing self-powered microbubbler (SM) for targeted decontamination of micrographs in dental implants. SMs are assembled by doping diatoms with MnO2 nanosheets. These particles are activated to generate O2 microbubbles in H2O2 solution via catalase-mimetic activity and can penetrate the biofilm structures. The resulting oxygen bubbles induce effective mechanical disruption and oxygenation within biofilm-mimicking gelatin hydrogels and Porphyromonas gingivalis biofilms found in the peri-implantitis-affected implants. Such biofilm removal from the microgap restored mechanical stability at implant abutment-fixture connections and reduced bacterial leakage. Multispecies biofilms from patient-derived implants were similarly decontaminated with the mixture of SM-H2O2 outperforming conventional antiseptics like 0.2% chlorhexidine and 3% H2O2 alone. This innovative approach extends beyond dental implants to address biofilm-associated challenges in various biomedical devices with microgap vulnerabilities. Overall, SM-based treatments will offer an efficient and nondamaging solution to enhance the sterility and longevity of various bioimplants with intricated and confined structure.

RevDate: 2025-04-22

Varadan P, Ra S, MR Rajendran (2025)

A Comparison Between Multisonic and Ultrasonic Irrigant Activation Techniques for Multispecies Biofilm Removal During Root Canal Disinfection: A Systematic Review.

Cureus, 17(3):e80938.

This systematic review aims to compare multisonic and ultrasonic irrigant activation techniques in polymicrobial biofilm removal. We conducted a literature search involving SCOPUS, PubMed, Cochrane, EBSCO host, and LILACS databases from inception to December 2024, in addition to a manual search using Google Scholar. The risk of bias assessment was done using the guidelines described for in vitro studies and the criteria for evaluation was based on JBI criteria and CRIS guidelines for quality assessment of in vitro studies. Three articles were included in the final analysis. The included studies evaluated biofilm removal in extracted teeth models incubated with biofilm; while two studies used quantitative polymerase chain reaction (qPCR) methodology, one used colony forming unit (CFU). Except in the study by Llerena et al., the GentleWave® multisonic System (GWS) outperformed ultrasonic irrigant activation (UI) in terms of biofilm removal. Despite the limitations of this systematic review, multisonic irrigant activation demonstrated similar efficacy in reducing intraradicular biofilm when compared to ultrasonic irrigant activation.

RevDate: 2025-04-22

Goda RM, Maghrabi IA, El-Badawy MF, et al (2025)

Developing a Urinary Catheter with Anti-Biofilm Coated Surface Using Phyto-Assisted Synthesis of Zinc Oxide Nanoparticles.

Infection and drug resistance, 18:1881-1893.

BACKGROUND: Biofilm-related infections represent one of the major challenging health problems that enhances antimicrobial resistance with subsequent treatment failure of catheter-associated urinary tract infections (CAUTIs).

AIM: This study aimed to employ and comprehensively characterize the use of nanoparticles to inhibit bacterial biofilm formation. Zinc oxide nanoparticles (ZnO-NPs) are considered one of the most important biofilm inhibitors.

METHODS: The current study aimed to characterize the influence of the bioreductive green synthesis of ZnO-NPs using pomegranate peel extract on bacterial colonization to protect against urinary catheter infections. ZnO-NPs were investigated for their physicochemical properties using UV, FTIR, Dynamic light scattering, and TEM. Catheters were coated with ZnO-NPs using Pistacia lentiscus (mastic), and the slow release of free zinc ions (Zn[+2]) from, the ZnO-NPs-coated catheters, was evaluated using the ICP-AES technique.

RESULTS: The current study revealed that catheter coated by ZnO-NPs exhibited a sustained antibiofilm activity against biofilm-forming and antibiotic-resistant clinical isolates of Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa strains.

CONCLUSION: The present study supports the efficiency of ZnO-NPs as a good candidate for prevention of biofilm formation.

RevDate: 2025-04-19
CmpDate: 2025-04-19

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

Biofilm formation and analysis of EPS architecture comprising polysaccharides and lipids by Pseudomonas aeruginosa and Escherichia coli on food processing surfaces.

Food research international (Ottawa, Ont.), 209:116274.

Biofilms are silent but formidable threats in seafood processing, where Pseudomonas aeruginosa and Escherichia coli can quickly transform contact surfaces into reservoirs of contamination. This study explores the dynamic biofilm formation on aluminum, silicone rubber, stainless steel, and polyethylene terephthalate over 24 and 72 h. Quantitative assays including Colony Forming Unit (CFU), Crystal Violet (CV), 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) revealed a significant increase in biofilm density, particularly on aluminum and silicone rubber. Fourier-Transform Infrared Spectroscopy (FTIR) and [1]H Nuclear Magnetic Resonance (NMR) analyses showed that biofilm EPS exhibits an evolving amphiphilic nature, with stable polysaccharides and increasing lipid content enhancing resilience. Confocal Laser Scanning Microscopy (CLSM), and Field Emission Scanning Electron Microscopy (FE-SEM) captured the shift from early attachment to mature, dense biofilms. These findings underscore the crucial impact of surface material on biofilm growth and the pressing need for tailored cleaning protocols to curb contamination risks in food processing environments.

RevDate: 2025-04-21
CmpDate: 2025-04-19

Davis SC, Avery JT, Gil J, et al (2025)

Protection with a collagen wound matrix containing polyhexamethylene biguanide supports innate wound healing in biofilm-infected porcine wounds.

Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society, 33(2):e70025.

Over 90% of chronic wounds have biofilm infections, making the need for inhibiting reformation of biofilm post-debridement paramount to support progression through the normal phases of wound healing. Herein, we describe a porcine wound model infected with methicillin-resistant Staphylococcus aureus (MRSA) and examine the ability of an antimicrobial barrier composed of native type I collagen and polyhexamethylene biguanide (PCMP) to serve as a barrier to protect wounds and support progression through the innate wound healing cascade. Wounds were inoculated with MRSA and allowed to form a biofilm for 72 h, subjected to standard of care sharp debridement, then either left untreated or received PCMP for 5, 10, 15 or 20 days. Wounds were assessed for bioburden, wound closure and expression of genes related to wound healing. Wounds treated with PCMP exhibited statistically lower MRSA levels compared to untreated controls and achieved 90% closure by 2 weeks of treatment. Gene expression analysis demonstrated that by reducing bacterial load, wounds progressed through the innate wound healing cascade, while untreated wounds exhibited a dampening of the immune response. Additionally, for randomly assigned wounds, PCMP was not reapplied at dressing changes to assess the impact of inconsistent wound protection. At all timepoints, a resurgence in bioburden was observed following removal of PCMP if the wounds had not fully closed. This study highlights the value of PCMP as an antimicrobial barrier and the importance of protecting wounds through closure and resolution.

RevDate: 2025-04-20

Jhuma TA, Dey SS, Sarkar R, et al (2025)

Biofilm inhibition and antagonism of Klebsiella pneumoniae by probiotic lactic acid bacteria (LAB) isolated from raw cow milk.

Microbial pathogenesis, 204:107603 pii:S0882-4010(25)00328-6 [Epub ahead of print].

Lactic acid bacteria (LAB) with their potential health benefits are naturally prevalent in dairy and fermented food products. This probiotic microbiota can be an alternative biological tool for controlling other pathogenic bacteria. The study aimed to isolate lactic acid bacteria (LAB) from raw cow milk and evaluate their probiotic potential. Twelve gram-positive isolates showing tolerance to bile salt, acid, and low pH were identified by 16S rRNA sequencing, which revealed the isolates belong to the genera including Lactococcus, Enterococcus, Streptococcus, Bacillus, and Weissella. In case of probiotic potential, the isolates exhibited arrays of probiotic properties: autoaggregation (33.65-84.63 %), co-aggregation (8.17-83.22 %), cell surface hydrophobicity for both polar (13.37-90.24 %) and non-polar solvents (5.52-53.58 %) and able to form biofilm (75 % weak, 16.67 % moderate and 8.33 % strong). Statistical analysis revealed the correlation pattern between the probiotic properties and showed a significant strong positive correlation between cell surface hydrophobicity and aggregation. Additionally, three isolates L. lactis, W. confusa, and E. gallinarum that were sensitive to antibiotics, able to produce biofilm, and did not contain virulence genes were able to reduce the biofilm formation of pathogen K. pneumoniae (1.3-4 log) in the co-culture assay. These Findings suggest that LAB from the raw cow milk could serve as a natural biocontrol agent for preventing and controlling K. pneumoniae biofilm formation and pave the way for innovative intervention of LAB in food safety and clinical settings.

RevDate: 2025-04-18

Nilavan E, Kumar A, Sivam V, et al (2025)

Molecular characterization, antibiotic resistance pattern, and biofilm formation of Vibrio parahaemolyticus isolated from tropical seafood.

Journal of AOAC International pii:8116182 [Epub ahead of print].

BACKGROUND: Vibrio parahaemolyticus in seafood poses a major public health concern, particularly in tropical regions.

OBJECTIVE: The present study aims to isolate, assess antibiotic susceptibility, and determine the biofilm-forming ability of V. parahaemolyticus strains isolated from seafood sold in Cochin, India.

METHODS: One hundred seafood samples were collected from retail markets in Cochin and analyzed for V. parahaemolyticus. Phenotypic identification was confirmed through biochemical assays and molecular characterization using polymerase chain reaction (PCR) targeting toxR, tdh, and trh genes. Biofilm formation was assessed using the microtiter plate-crystal violet assay, and antibiotic resistance was determined using the disc diffusion method.

RESULTS: V. parahaemolyticus was detected in 43.0% (43/100) of the total seafood analyzed. A total of 43 isolates were confirmed by the toxR gene, of which five carried the tdh gene, while none harbored the trh gene. Antimicrobial susceptibility testing revealed 100% resistance to ampicillin, whereas all isolates were fully susceptible to chloramphenicol. The multiple antibiotic resistance (MAR) index ranged from 0.13 to 0.50. Notably, some multidrug-resistant isolates exhibited strong biofilm formation at 37 °C.

CONCLUSION: The high prevalence of antibiotic-resistant V. parahaemolyticus in seafood sold in Cochin and their ability to form biofilms underscores the need for rigorous monitoring and effective control strategies to safeguard public health.

RevDate: 2025-04-19

Wardell SJT, Yung DBY, Nielsen JE, et al (2025)

A biofilm-targeting lipo-peptoid to treat Pseudomonas aeruginosa and Staphylococcus aureus co-infections.

Biofilm, 9:100272.

Antibiotic-resistant bacterial infections are a significant clinical challenge, especially when involving multiple species. Antimicrobial peptides and their synthetic analogues, peptoids, which target bacterial cell membranes as well as intracellular components, offer potential solutions. We evaluated the biological activities of novel peptoids TM11-TM20, which include an additional charged NLys residue, against multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus, both in vitro and in vivo. Building on insights from previously reported compounds TM1-TM10, the lipo-peptoid TM18, which forms self-assembled ellipsoidal micelles, demonstrated potent antimicrobial, anti-biofilm, and anti-abscess activity. Transcriptome sequencing (RNA-seq) revealed that TM18 disrupted gene expression pathways linked to antibiotic resistance and tolerance, and biofilm formation in both pathogens. Under dual-species conditions, TM18 induced overlapping but attenuated transcriptional changes, suggesting a priming effect that enhances bacterial tolerance. In a murine skin infection model, TM18 significantly reduced dermonecrosis and bacterial burden in mono-species infections. When combined with the antibiotic meropenem, they synergistically nearly cleared co-infections. Our findings highlight that TM18 has potential as a novel therapeutic for combating antibiotic-resistant pathogens and associated biofilm-driven tolerance.

RevDate: 2025-04-18

Randhawa S, Saini TC, Bathla M, et al (2025)

Biofilm Biology to Brain Health: Harnessing Microbial Wisdom to Uncover Amyloid Dissociating Bifunctional Nano Chaperones for Alzheimer's Therapeutics.

ACS chemical neuroscience [Epub ahead of print].

Microbial infections have long been implicated in the gut-brain link to Alzheimer's disease (AD). These infections may influence AD development either directly, through brain invasion, or indirectly via bacterial metabolites crossing the blood-brain-barrier (BBB) or interacting with the enteric nervous system (ENS). Such findings have inspired clinicians to repurpose antimicrobial drugs for AD, yielding promising results. However, the sole bacterial link to AD may be insufficiently understood. Bacterial amyloid presence in biofilms is well-documented, with certain bacterial proteins exacerbating amyloid formation while others inhibit it. For instance, Curli-specific gene protein C (CsgC) in E. coli suppresses curli amyloid formation. This review investigates the possibility of human CsgC-like proteins, identifying beta-2 microglobulin (β2M) and E3 ubiquitin ligases (E3s) as potential analogs that may influence amyloid degradation. We propose that nanoparticles (NPs) could serve as platforms to anchor these proteins, forming Amyloid Dissociating Bifunctional NanoChaperones (ADBiNaCs) with enhanced antiamyloidogenic activity. This innovative approach holds promise for novel AD treatment strategies, meriting further investigation into the role of bacterial and human amyloid-modulating proteins in AD pathology.

RevDate: 2025-04-17

Garcia IM, Araújo-Neto VG, Balbinot G, et al (2025)

Dental adhesives incorporated with alkyl trimethyl ammonium bromide-loaded titanium oxide nanotubes for sustained bioactive and anti-biofilm protection.

Dental materials : official publication of the Academy of Dental Materials pii:S0109-5641(25)00595-0 [Epub ahead of print].

OBJECTIVES: This study aimed to formulate experimental dental adhesives with alkyl trimethyl ammonium bromide-loaded titanium oxide nanotubes (ntTiO2/ATAB) and evaluated their physicochemical properties, antimicrobial activity, mineral deposition, and cytotoxicity.

METHODS: ntTiO₂/ATAB was synthesized, characterized, and added into an experimental adhesive resin. The filler ntTiO₂/ATAB was added at 1, 2.5, and 5 wt% (G1 %, G2.5 %, G5 %) in the adhesive. A control group (G0 %) without ntTiO₂/ATAB was also prepared and used in all tests. The adhesives were analyzed for degree of conversion (DC%), softening in solvent, radiopacity, antibacterial activity against saliva-derived microcosm, mineral deposition capability, and cytotoxicity.

RESULTS: Analytical techniques, including TEM, FTIR, UV-Vis, and micro-Raman spectroscopy, confirmed the structure and chemical composition of the ntTiO₂/ATAB. A DC% over 60 % was observed for all groups, with no adverse impact on radiopacity or softening in solvent. Antibacterial testing indicated that increasing ntTiO₂/ATAB concentration led to reduced colony-forming units of critical microorganisms, with this effect sustained over a one-year aging period. Mineral deposition tests showed enhanced phosphate presence over the samples with higher ntTiO₂/ATAB concentrations. There were no statistical differences in human cell viability among groups.

SIGNIFICANCE: The dental adhesives formulated with ntTiO2/ATAB demonstrated suitable physical and chemical properties, including reliable bond strength to dentin previously tested. They also exhibited antibacterial effects against caries-related microorganisms even after aging, promoted bioactivity through mineral deposition, and showed no cytotoxicity against human cells. These adhesives represent a promising strategy to assist in reducing the risk of recurrent caries and preserve the material-dentin interface properties over time.

RevDate: 2025-04-17
CmpDate: 2025-04-17

Gao Q, Zhu F, Wang M, et al (2025)

A new perspective on the simultaneous removal of nitrogen, tetracycline, and phosphorus by moving bed biofilm reactor under co-metabolic substances.

Journal of environmental sciences (China), 155:431-441.

With the burgeoning growth of aquaculture industry, high concentration of NH4[+]-N, phosphorus and tetracycline are the prevalent pollutants in aquaculture wastewater posing a significant health risk to aquatic organisms. Therefore, an effective method for treating aquaculture wastewater should be urgently explored. Simultaneous removal of NH4[+]-N, phosphorus, tetracycline, and chemical oxygen demand (COD) in aquaculture wastewater was developed by moving bed biofilm reactor (MBBR) under co-metabolic substances. The result showed that co-metabolism substances had different effects on MBBR performance, and 79.4 % of tetracycline, 68.2 % of NH4[+]-N, 61.3 % of total nitrogen, 88.3 % of COD, and 38.1 % of total phosphorus (TP) were synchronously removed with sodium acetate as a co-metabolic carbon source. Protein (PN), polysaccharide (PS), and electron transfer system activity were used to evaluate the MBBR performances, suggesting that PN/PS ratio was 1.48, 0.91, 1.07, 3.58, and 0.79 at phases I-V. Additionally, a mode of tetracycline degradation and TP removal was explored, and the cell apoptosis was evaluated by flow cytometry. The result suggested that 74 %, 83 %, and 83 % of tetracycline were degraded by extracellular extracts, intracellular extracts, and cell debris, and there was no difference between extracts and non-enzyme in TP removal. The ratio of viable and dead cells from biofilm reached 33.3 % and 7.68 % with sodium acetate as a co-metabolic carbon source. Furthermore, Proteobacteria and Bacteroidetes in biofilm were identified as the dominant phyla for tetracycline and nutrients removal. This study provides a new strategy for tetracycline and nutrients removal from aquaculture wastewater through co-metabolism.

RevDate: 2025-04-17

Ferreira NS, de Jesus Catten Moreno T, Eduardo de Souza Duarte C, et al (2025)

Exploring the antifungal potential and action mechanism of pomegranate peel extract against Candida species in planktonic and biofilm conditions.

Microbial pathogenesis pii:S0882-4010(25)00321-3 [Epub ahead of print].

Candidiasis, a fungal infection caused by Candida spp., poses a growing clinical challenge due to the development of antifungal resistance. This study assessed the efficacy of dry crude pomegranate peel extract (DCPPE) as an antifungal agent against Candida infections (C. albicans, C. parapsilosis, C. krusei and C. glabrata) by investigating its effects on fungal growth, biofilm disruption, and fungal cell membrane integrity, as well as evaluating its safety regarding hemolysis at different concentrations. The DCPPE exhibited inhibitory activity against all tested Candida strains, with MIC of 1% (10 mg/mL). These results may be associated with the phenolic composition of the peel extract, which includes compounds like gallic acid, punicalagin A, punicalagin B, and ellagic acid. Furthermore, the DCPPE disrupted Candida biofilms and demonstrated safety with respect to hemolysis at concentrations up to 60 mg/mL. However, no evidence of a direct interaction with the fungal cell wall or ergosterol in the fungal membrane was found. Thus, our results highlight the potential of DCPPE as a promising alternative for the treatment of candidiasis. Nevertheless, further research is needed to fully clarify the underlying mechanisms and optimize its clinical efficacy.

RevDate: 2025-04-19

da Silva WSFL, Amorim PK, Ferreira GRS, et al (2025)

Moringa oleifera seed preparations containing the lectin WSMoL inhibit growth, cell aggregation, and biofilm production of Listeria monocytogenes.

Microbial pathogenesis, 204:107600 pii:S0882-4010(25)00325-0 [Epub ahead of print].

This work evaluated the antibacterial properties of aqueous extract (AE), protein-rich fraction (PF), and isolated water-soluble lectin (WSMoL) from Moringa oleifera Lam. seeds against the gram-positive bacterium Listeria monocytogenes, which causes listeriosis. Foodborne bacterial infections, which are facilitated by biofilm formation, pose significant public health threats. Listeriosis is an infection that involves bacteremia, meningitis, or meningoencephalitis. The strains N53-1 and EGD-e were assessed in this work. Bacteriostatic and bactericidal effects on planktonic cells were assessed by broth microdilution assay and flow cytometry. Possible combined effects with antibiotics (ciprofloxacin and cephalexin) were also determined, as well as the impact of all preparations on bacterial aggregation and biofilm formation. AE, PF and WSMoL presented minimum inhibitory concentration (MIC) ranging from 250 to 300 μg/mL for N53-1, and between 150 and 250 μg/mL for EGD-e. AE and WSMoL did not show bactericidal action but PF was bactericidal to EGD-e (minimal bactericidal concentration: 1500 μg/mL). AE, PF, and WSMoL demonstrated synergistic effects with ciprofloxacin, while AE and PF were synergic together with cephalexin. Moreover, AE, PF and WSMoL showed an inhibitory effect on aggregation of cells of both strains. At 0.97 μg/mL, WSMoL inhibited 95 % the biofilm formation by N53-1, while PF at 4.68 μg/mL elicited a biofilm inhibition of 87 % on the same strain. The data stimulate more studies assessing the potential of crude and purified preparations from M. oleifera containing the lectin WSMoL to combat the causer of listeriosis, as synergistic agents and as aggregation inhibitors.

RevDate: 2025-04-17

Yang Y, Wang Y, J Shi (2025)

Aerobic biofilm systems outperform anaerobic and anoxic regimes in 2,4-dimethylphenol degradation: Microbial synergy and metabolic mechanisms.

Journal of environmental management, 382:125408 pii:S0301-4797(25)01384-2 [Epub ahead of print].

The efficient biodegradation of 2,4-dimethylphenol (2,4-DMP), a toxic and recalcitrant phenolic pollutant, remains a critical challenge in wastewater treatment, with ongoing debate regarding the optimal dissolved oxygen (DO) regime for biofilm-based systems. To resolve this, four biofilm reactors-anaerobic (R1), anoxic (R2), microaerobic (R3), and aerobic (R4)-were operated under a DO gradient (0.3-8.0 mg/L). When influent 2,4-DMP concentrations increased from 25 to 300 mg/L, removal efficiencies declined significantly in R1-R3 (9.0 %, 44.8 %, and 58.8 %, respectively), whereas R4 maintained 100 % removal regardless of loading. Rapid degradation occurred within 8-16 h in R4, correlating with DO consumption from 8.0 to 5.0 mg/L. Aerobic conditions eliminated dependence on extracellular polymeric substances (EPS) for pollutant sequestration, as complete mineralization negated intermediate accumulation. Microbial analysis revealed Zoogloea (18.92 % abundance), Prosthecobacter, and Ferruginibacter as keystone aerobic bacteria, encoding aromatic ring-hydroxylating dioxygenases (RHDs) for 2,4-DMP hydroxylation and β-ketoadipate pathway activation. Concurrently, fungal genera Cutaneotrichosporon (74.50 %) and Kalenjinia were enriched in R4, contributing laccase-mediated ring cleavage. Synergy between bacterial oxidative pathways and fungal ligninolytic systems enabled sustained COD removal (95.54 %) without biofilm destabilization. These findings conclusively demonstrate aerobic biofilms' superiority in 2,4-DMP treatment, driven by metabolic completeness, energy-efficient respiration, and cross-kingdom functional partitioning.

RevDate: 2025-04-17

Lee Y-J, Abdullah M, Chang Y-F, et al (2025)

Characterization of proteins present in the biofilm matrix and outer membrane vesicles of Histophilus somni during iron-sufficient and iron-restricted growth: identification of potential protective antigens through in silico analyses.

mBio [Epub ahead of print].

There is limited efficacy in vaccines currently available to prevent some animal diseases of bacterial origin, such as bovine respiratory disease caused by Histophilus somni. Protective efficacy can potentially be improved if bacterial antigens that are expressed in the host are included in vaccines. During H. somni infection in the bovine host, biofilms become established, and the availability of essential iron is restricted. To investigate further, the protein composition of spontaneously released outer membrane vesicles (OMVs) during iron-sufficient and iron-restricted growth and the proteins expressed in the biofilm matrix were analyzed and compared. Proteomic analysis revealed a dramatic physiological change in H. somni as it transitioned from the planktonic form to the biofilm mode of growth. All transferrin-binding proteins (Tbps) previously identified in H. somni were detected in the OMVs, suggesting that OMVs could induce antibodies to these proteins. Two TbpA-like proteins and seven total proteins were present in the OMVs only when iron was restricted, indicating the expression of these Tbps was differentially regulated. More proteins associated with quorum-sensing (QS) signaling were detected in the biofilm matrix compared with proteins in the OMVs, supporting a link between QS and biofilm formation. Proteins ACA31267.1 (OmpA) and ACA32419.1 (TonB-dependent receptor) were present in the OMV and biofilm matrix and predicted to be potential protective antigens using an immuno-bioinformatic approach. Overall, the results support the development of novel vaccines that contain OMVs obtained from bacteria grown to simulate the in vivo environment, and possibly biofilm matrix, to prevent diseases caused by bacterial pathogens.IMPORTANCEBovine respiratory disease (BRD) is the most economically important disease affecting the cattle industry. Available BRD vaccines consist of killed bacteria but are not very effective. Poor vaccine efficacy may be because the phenotype of bacteria in the host differs from the phenotype of cultured bacteria. Following host infection, virulent bacteria can express transferrin-binding proteins (Tbps) not expressed in culture medium but are required to sequester iron from host proteins. During chronic infections, such as BRD, bacteria can form a biofilm consisting of novel protein and polysaccharide antigens. The unique proteins expressed on outer membrane vesicles (OMVs) of Histophilus somni (a BRD pathogen) in the absence of iron and as a biofilm were identified and characterized. At least two TbpA-like proteins were expressed in OMVs only under iron-limiting conditions. Quorum-sensing-associated proteins were identified in the H. somni biofilm matrix. In silico analysis identified potential protein targets for vaccine development.

RevDate: 2025-04-17

Matavacas J, C von Wachenfeldt (2025)

Protein Homeostasis Impairment Alters Phenotypic Heterogeneity of Biofilm Communities.

Molecular microbiology [Epub ahead of print].

Biofilms are highly organized, cooperating communities of microorganisms encased in a self-produced extracellular matrix, providing resilience against external stress such as antimicrobial agents and host defenses. A hallmark of biofilms is their phenotypic heterogeneity, which enhances the overall growth and survival of the community. In this study, we demonstrate that removing the dnaK and tig genes encoding the core molecular chaperones DnaK (Hsp70 homolog) and Trigger factor disrupted protein homeostasis in Bacillus subtilis and resulted in the formation of an extremely mucoid biofilm with aberrant architecture, compromised structural integrity, and altered phenotypic heterogeneity. These changes include a large reduction in the motile subpopulation and an overrepresentation of matrix producers and endospores. Overproduction of poly-γ-glutamic acid contributed crucially to the mucoid phenotype and aberrant biofilm architecture. Homeostasis impairment, triggered by elevated temperatures, in wild-type cells led to mucoid and aberrant biofilm phenotypes similar to those observed in strains lacking both dnaK and tig. Our findings show that disruption of protein homeostasis, whether due to the absence of molecular chaperones or because of environmental factors, severely changes biofilm features.

RevDate: 2025-04-18

Dong Q, Mattes TE, GH LeFevre (2025)

Development of a Novel PCB-Degrading Biofilm Enriched Biochar Encapsulated with Sol-Gel: A Protective Layer to Sustain Biodegradation Activity.

ACS ES&T engineering, 5(4):883-898.

Paraburkholderia xenovorans LB400 biofilms hold the potential to degrade PCBs in contaminated sediment. Nevertheless, unfavorable environmental conditions (e.g., salinity, temperature, and shear force) can interfere with biofilm stability and affect biodegradation potential. Sol-gel encapsulation has been used to protect planktonic cell function due to high material stability and absence of cell washout but has not been employed for biofilm protection. Our study is the first to develop sol-gel application on biofilm-enriched black carbons and evaluate efficacy for prolonging biodegradation potential. We systematically tuned multiple sol-gel recipes to coat biofilms and measured the impact of the sol-gel coating on cell survival and pollutant degradation. The developed sol-gel completely encapsulated biofilm-enriched black carbons and produced both high porosity and appropriate pore size that allowed pollutant transfer from the surrounding environment to the biofilms. The sol-gel maintained physical integrity under saline conditions (simulating marine and estuary sediments) and continuously applied shear force. Additionally, the encapsulated biofilms degraded benzoate, a proof-of-concept organic molecule, and extended biofilm attachment and cell viability for over three months without a carbon and energy source. Our study demonstrates that sol-gel helps sustain PCB-degrading biofilms under environmentally relevant conditions. This novel sol-gel application can potentially improve the bioaugmentation effectiveness and enhance degradation of environmental pollutants.

RevDate: 2025-04-18

Trego A, Morabito C, Bourven I, et al (2025)

Size matters: Anaerobic granules exhibit distinct ecological and physico-chemical gradients across biofilm size.

Environmental science and ecotechnology, 25:100561.

Anaerobic biological decomposition of organic matter is ubiquitous in Nature wherever anaerobic environments prevail, and is catalysed by hydrolytic, fermentative, acetogenic, methanogenic, and various other groups. It is also harnessed in innovative ways in engineered systems that may rely on small (0.1-4.0 mm), spherical, anaerobic granules. These biofilms are crucial to the operational success of a range of widely applied engineered-ecosystems designed for wastewater treatment. The structure and function of granule microbiomes underpin their utility. Here, granules were separated into ten size fractions (proxies for age), hypothesizing that small granules are 'young' and larger ones are 'old'. Gradients were observed across size in terms of volatile solids, density, settleability, biofilm morphology, methanogenic activity, and profiles of extracellular polymeric substances, suggesting ongoing development of physico-chemical characteristics as granules develop. Short-read amplicon sequencing indicated a negative relationship between granule size and community diversity. Furthermore, as size increased, the methanogenic archaea dominated the microbiome. Small granules were found to harbour a sub-group of highly specific taxa, and the identification of generalists and specialists may point to substantial resilience of the microbiome. The findings of this study indicate opportunities for precision management of wastewater treatment systems. They suggest that size is an important indicator for aggregate utility - size may, indeed, determine many of the characteristics of both the individual-granule microbiomes and the overall function of a wastewater treatment system.

RevDate: 2025-04-18

Liu H, Ma Y, Xiao J, et al (2025)

Biofilm-mediated mass transfer of sorbed benzo[a]pyrene from polyethylene to seawater.

Environmental pollution (Barking, Essex : 1987), 374:126257 pii:S0269-7491(25)00630-X [Epub ahead of print].

Plastic waste, including microplastics (MPs), often serves as a carrier for hydrophobic organic contaminants (HOCs) and additives in aquatic environments. However, little is known about the fate of contaminants in plastics, especially under the influence of biofilm in field conditions. In this study, polyethylene (PE) was pre-sorbed with varying concentrations of benzo[a]pyrene (BaP), a non-polar contaminant, and deployed in situ to study desorption kinetics under natural biofilm colonization. Based on the desorption kinetics of BaP from PE, a mass transfer model was developed to describe the desorption of non-polar contaminants from PE under the influence of biofilm formation. This study proved that biofilm, acting as an intermediary between plastics and the aquatic environment, did not serve as a sink for plastic-sorbed BaP, but accelerated the desorption process of BaP by reducing the partition coefficient between the plastic and the boundary layer. Furthermore, based on our developed model (IABL-ODD), the effects of biofilm on the fate of other non-polar and weakly polar contaminants in PE were predicted. This study highlights the influence of biofilm on the desorption of hydrophobic contaminants from plastics in field conditions and also informs future work on more relevant processes such as additive leaching.

RevDate: 2025-04-16

Ma H, Chen S, Lv L, et al (2025)

Large-sized aerobic granular biofilm: stable biotechnology to improve nitrogen removal and reduce sludge yield.

Bioresource technology pii:S0960-8524(25)00509-7 [Epub ahead of print].

Three parallel sequencing batch reactors (control, small-sized polyurethane sponge (PUS) (3.0 mm), and large-sized PUS (10.0 mm)) were used to investigate aerobic granular biofilm (AGB) characteristics. Results show that 10.0 mm PUS facilitated rapid formation of large-sized AGB (AGBL), which exhibited higher biomass concentration (8.5 g/L) and faster settling velocity (69.2-159.3 m/h) than aerobic granular sludge (AGS) (3.2 g/L and 38.6-80.0 m/h). The AGBL system also maintained long-term structural stability with a lower instability coefficient (0.004-0.018 min[-1]) than AGS (0.053-0.090 min[-1]). Additionally, during long-term operation, the AGBL system achieved excellent removal efficiencies for NH4[+]-N (99.6 ± 0.4 %) and total nitrogen (92.3 ± 2.6 %), and exhibited a lower sludge yield (0.05 gVSS/gCOD) than AGS (0.14 gVSS/gCOD). The larger size and compact structure of AGBL increased anoxic/anaerobic zones, enriching denitrifying and hydrolytic/fermentative bacteria. These findings highlight AGBL with large PUS as a more promising biotechnology for practical applications than conventional AGS.

RevDate: 2025-04-16

Zhao C, Zhang W, Guo Y, et al (2025)

Flocculent sludge outperforms filler biofilm for high salinity oilfield produced water treatment: Performance, metabolic pathways, and microbial communities.

Journal of hazardous materials, 492:138217 pii:S0304-3894(25)01132-X [Epub ahead of print].

High-salinity oilfield produced water (OPW) posed significant challenges for biological treatment due to its complex composition and toxic effects. This study systematically compared the performance of heterotrophic ammonia assimilation (HAA) constructed by three filler biofilms (soft fiber filler, cylindrical filler, and sponge filler) and a flocculent sludge in degrading petroleum hydrocarbons. The dynamic mixing and suspended-growth nature of flocculent sludge ensured efficient substrate distribution and microbial interaction, enhancing treatment performance of NH4[+]-N, COD and total petroleum hydrocarbons. Due to mass transfer limitations and ecological specialization, the impact loading capacity of the HAA biofilm reactors to actual OPW were limited compared with flocculent sludge. Halomonas and Marinobacter were enriched in four bioreactors as the main forces of halotolerant hydrocarbon degraders and nitrogen assimilation main forces. The flocculent sludge showed a stronger microbial network, increased functional gene abundance, and higher enzymatic activity for key degradation pathways compared to biofilm systems. KEGG-based gene and enzyme activity analysis revealed the superior metabolic potential of flocculent sludge for degrading recalcitrant hydrocarbons in high-salinity oilfield-produced water, including alkanes, aromatics and polycyclic aromatic hydrocarbons. These findings highlight the superior potential of flocculent sludge system for treating high-salinity OPW through efficient microbial and metabolic interactions.

RevDate: 2025-04-16

Bian Y, Guo X, He X, et al (2025)

Study on adsorption and desorption characteristics of lead pollution by biofilm in drinking water pipeline from multi-factor perspective.

Journal of hazardous materials, 492:138284 pii:S0304-3894(25)01199-9 [Epub ahead of print].

This study investigates lead adsorption and desorption behaviors in biofilms on drinking water pipeline materials (PVC, 304 stainless steel, copper) under varying flow rate, pH, and residual chlorine. Biofilms on stainless steel exhibited the highest adsorption capacity (450.81 μmol/m[2]), whereas PVC biofilms had the greatest desorption potential (25.30 μmol/m[2]). Optimal lead adsorption occurred at neutral pH (7.5), low flow velocity (0.10 m/s), and moderate chlorine concentration (0.3 mg/L). Optimal lead adsorption occurred at neutral pH (7.5), low flow velocity (0.10 m/s), and moderate chlorine concentration (0.3 mg/L). In contrast, higher flow velocities, acidic conditions, and elevated chlorine levels promoted desorption or inhibited interactions. PVC biofilms exhibited the highest biomass (1.58 × 10[6] CFU/cm[2]) and extracellular polymeric substances (EPS) (348 mg/m[2]), correlating with increased lead adsorption. Functional analysis revealed a higher abundance of ion-transport-related (functions associated with the movement of ions such as heavy metals across microbial cell membranes) functions in PVC biofilms, contributing to enhanced stability. The study offers valuable insights for optimizing pipe material selection and operational strategies to reduce lead contamination in water systems.

RevDate: 2025-04-16

Briega I, Garde S, Sánchez C, et al (2025)

Evaluation of Biofilm Production and Antibiotic Resistance/Susceptibility Profiles of Pseudomonas spp. Isolated from Milk and Dairy Products.

Foods (Basel, Switzerland), 14(7): pii:foods14071105.

Dairy-borne Pseudomonas spp., known for causing spoilage, may also exhibit antibiotic resistance and form biofilms, enhancing their persistence in dairy environments and contaminating final products. This study examined biofilm formation and antibiotic resistance in 106 Pseudomonas spp. strains isolated from milk, whey, and spoiled dairy products. Phylogenetic analysis (based on partial ileS sequences) grouped most strains within the P. fluorescens group, clustering into the P. fluorescens, P. gessardii, P. koorensis, and P. fragi subgroups. Biofilm formation in polystyrene microplates was assessed at 6 °C and 25 °C by crystal violet staining. After 48 h, 72% and 65% of Pseudomonas strains formed biofilms at 6 °C and 25 °C, respectively, with higher biomass production at 6 °C. High biofilm producers included most P. fluorescens, P. shahriarae, P. salmasensis, P. atacamensis, P. gessardii, P. koreensis, and P. lundensis strains. The adnA gene, associated with biofilm formation, was detected in 60% of the biofilm producers, but was absent in P. fragi, P. lundensis, P. weihenstephanensis, and P. putida. Antibiotic susceptibility was tested using the disk diffusion method. All strains were susceptible to amikacin and tobramycin; however, 73% of the strains were resistant to aztreonam, 28% to imipenem and doripenem, 19% to ceftazidime, 13% to meropenem, and 7% to cefepime. A multiple antibiotic resistance index (MARI) > 0.2 was found in 30% of the strains, including multidrug-resistant (n = 15) and extensively drug-resistant (n = 3) strains. These findings highlight Pseudomonas spp. as persistent contaminants and antibiotic resistance reservoirs in dairy environments and products, posing public health risks and economic implications for the dairy industry.

RevDate: 2025-04-16

Campo-Pérez V, Julián E, E Torrents (2025)

Interplay of mycobacterium abscessus and Pseudomonas aeruginosa in experimental models of coinfection: Biofilm dynamics and Host immune response.

Virulence [Epub ahead of print].

The incidence of infection by nontuberculous mycobacteria, mainly Mycobacterium abscessus, is increasing in patients with cystic fibrosis and other chronic pulmonary diseases, leading to an accelerated lung function decline. In most cases, M. abscessus coinfects Pseudomonas aeruginosa, the most common pathogen in these conditions. However, how these two bacterial species interact during infection remains poorly understood. This study explored their behaviour in three relevant pathogenic settings: dual-species biofilm development using a recently developed method to monitor individual species in dual-species biofilms, coinfection in bronchial epithelial cells, and in vivo coinfection in the Galleria mellonella model. The results demonstrated that both species form stable mixed biofilms and reciprocally inhibit single-biofilm progression. Coinfections in bronchial epithelial cells significantly decreased cell viability, whereas in G. mellonella, coinfections induced lower survival rates than individual infections. Analysis of the immune response triggered by each bacterium in bronchial epithelial cell assays and G. mellonella larvae revealed that P. aeruginosa induces the overexpression of proinflammatory and melanization cascade responses, respectively. In contrast, M. abscessus and P. aeruginosa coinfection significantly inhibited the immune response in both models, resulting in worse consequences for the host than those generated by a single P. aeruginosa infection. Overall, this study highlights the novel role of M. abscessus in suppressing immune responses during coinfection with P. aeruginosa, emphasizing the clinical implications for the management of cystic fibrosis and other pulmonary diseases. Understanding these interactions could inform the development of new therapeutic strategies to mitigate the severity of coinfections in vulnerable patients.

RevDate: 2025-04-17

Watkins JD, Abdellaoui H, Barton E, et al (2025)

Dataset: Compositional analysis and hydrothermal liquefaction of a high-ash microalgae biofilm.

Data in brief, 60:111490.

This dataset contains biochemical composition data and hydrothermal liquefaction (HTL) yield results for a high-ash microalgae biofilm which was cultivated in effluent from a mesophilic anaerobic digester using polyethylene rotating algae biofilm reactors (RABRs). These data were originally collected for use in a techno-economic analysis of biocrude, biodiesel, and bioplastic production from algae that was cultivated using RABRs for municipal wastewater reclamation. Biochemical data for the microalgae biomass includes bulk protein, measured both using the Bradford protein assay and by multiplying total N; carbohydrate content, measured using a 3-methyl-2-benzothiazolinone hydrazone / dithiothreitol (MBTH/DTT) assay; total lipid content, measured using a sulpho-phospho-vanillin method; hexane-extractable lipid content, measured by mass difference after extraction with methanol and hexane; ash content, measured by mass difference after incineration at 550°C; moisture content of the harvested biofilm slurry, measured by mass difference after drying at 60°C, mineral composition, measured using an inductively-coupled plasma spectrophotometer; higher heating value, measured using a bomb calorimeter; and CHNS-O elemental composition, measured using an elemental analyser. Data reported for the HTL product phases include mass yields for each phase (solid, aqueous, biocrude, gas); higher heating value of the biocrude phase, measured using a bomb calorimeter; elemental composition of the biocrude phase, measured using an elemental analyzer; and chemical properties of the aqueous phase, including pH, chemical oxygen demand (HACH method 8000), total nitrogen (HACH method 10,208), total ammonia (HACH method 10,301), total phosphorus (HACH method 10,209/10,210), and total organic carbon (HACH method 10,267). Currently, the effects of ash composition and HTL heating rate on biocrude yields and on N and P partitioning into biocrude, aqueous, and solid phases are not clearly defined. Models used to predict biocrude yields after HTL of microalgae are commonly trained using data collected from numerous studies. This dataset contains the feedstock composition data and ramp rate data necessary to help define the effects of ash content on biocrude yields after HTL and can be reused to help train yield-prediction models for the HTL of microalgae and other feedstocks.

RevDate: 2025-04-17
CmpDate: 2025-04-16

Manandhar S, Karn D, Shrestha MR, et al (2025)

Biofilm formation, methicillin resistance and SCCmec types among Staphylococcus aureus isolated from clinical samples from a tertiary care hospital, in Nepal.

BMC infectious diseases, 25(1):534.

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a human pathogen that can cause hospital and community acquired infections. Biofilm formation is a major virulence factor contributing to its pathogenicity. This study aimed to detect biofilm formation ability among methicillin resistant Staphylococcus aureus (MRSA) clinical isolates and determine SCCmec types.

METHODS: A total of 115 S. aureus were isolated from various clinical samples collected at Nepal Armed Police Hospital from August 2022 to February 2023. The antibiotic susceptibility test was performed via a modified Kirby Bauer disc diffusion method following CLSI guidelines. Phenotypic detection of biofilm formation was performed by microtiter plate assay. Polymerase chain reaction was performed to detect mecA, icaA and SCCmec types.

RESULTS: More than 90% of the isolates were resistant to cefixime and penicillin. Among the total isolates, 66% were multidrug resistant. The disc diffusion method detected 60% of the isolates as MRSA, with 15 isolates lacking the mecA gene. Different levels of biofilm biomass were observed among 86 (75%) of the isolates by microtiter plate method. PCR revealed the presence of the icaA gene in a low number of the isolates (16%). Compared with biofilm nonproducer isolates, biofilm producing S. aureus isolates presented a greater incidence of antibiotic resistance with multi drug resistance (MDR). SCCmec type V (21%) predominated, followed by type II (13%) and most of them were MDR and biofilm producers.

CONCLUSIONS: Our results indicate a relatively high incidence of community acquired S. aureus circulating in the hospital setting. This study is the first to explore the associations between SCCmec types and biofilm formation among clinical isolates in Nepal. Monitoring the prevalence of biofilm producing S. aureus provides valuable insights into the evolving epidemiology of healthcare associated infections, facilitating the development of targeted infection control strategies.

RevDate: 2025-04-17
CmpDate: 2025-04-15

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

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

NPJ biofilms and microbiomes, 11(1):58.

Extracellular DNA (eDNA) is crucial for the structural integrity of bacterial biofilms as they undergo transformation from B-DNA to Z-DNA as the biofilm matures. This transition to Z-DNA increases biofilm rigidity and prevents binding by canonical B-DNA-binding proteins, including nucleases. One of the primary defenses against bacterial infections are Neutrophil Extracellular Traps (NETs), wherein neutrophils release their own eDNA to trap and kill bacteria. Here we show that H-NS, a bacterial nucleoid associated protein (NAP) that is also released during biofilm development, is able to incapacitate NETs. Indeed, when exposed to human derived neutrophils, H-NS prevented the formation of NETs and lead to NET eDNA retraction in previously formed NETs. NETs that were exposed to H-NS also lost their ability to kill free-living bacteria which made H-NS an attractive therapeutic candidate for the control of NET-related human diseases. A model of H-NS release from biofilms and NET incapacitation is discussed.

RevDate: 2025-04-15

Stewart S, Chalamalasetti S, Ruiz-Llacsahuanga B, et al (2025)

The effect of commercial sanitizers on Listeria monocytogenes (planktonic and biofilm forms) experimentally inoculated materials commonly used during tree-fruit harvesting.

Letters in applied microbiology pii:8113970 [Epub ahead of print].

This study compares the efficacy of commercially available sanitizers in reducing L. monocytogenes planktonic and biofilm form on surfaces commonly used during tree fruit harvesting. Planktonic L. monocytogenes cells were grown to create a bacterial lawn and inoculated on high density polyethylene plastic, wood, or nylon. Biofilms were grown for 96 h in a Centers for Disease Control reactor on the same surfaces. Bacteria were exposed to free chlorine, peroxyacetic acid, silver-dihydrogen citrate, steam and chlorine dioxide. In planktonic forms, peroxyacetic acid and silver-dihydrogen citrate, applied for 2 min resulted in ≥ 3-log reduction regardless surface type (P < 0.05). Steam and chlorine dioxide efficacy differed significantly by surface type. When applied to Listeria biofilms, steam, chlorine, peroxyacetic acid and chlorine dioxide resulted in an overall significant difference compared to untreated coupons for all surfaces (P < 0.05). Silver-dihydrogen citrate significantly affected population on plastic (P < 0.05), but not on wood or nylon. For porous surfaces few treatments, such as peroxyacetic acid (for nylon) and chlorine dioxide (for wood), resulted in a ≥ 3 log reduction of both forms. Interactions between sanitizer, surfaces and exposure time should be considered by tree fruit harvesting facilities when determining sanitation strategies to be implemented.

RevDate: 2025-04-15

Qi Z, Hua X, Li A, et al (2025)

Degradation of organic pollutant by natural biofilm based biophotovoltaic cells: The combined role of illumination, reactive oxygen species, and enhanced electron transfer.

Bioresource technology pii:S0960-8524(25)00503-6 [Epub ahead of print].

Autotrophic biofilms in natural water can produce reactive oxygen species (ROS) and degrade organic pollutants. To test the feasibility of applying natural biofilms in biophotovoltaic (BPV) cells, a simple single-chamber BPV using biofilms developed in lake water as the microbial anode was constructed, and electricity production and pollutant removal capacity of the BPV were evaluated. The natural biofilm BPV (NB-BPV) established was a robust and self-sustaining BPV with positive light response in electricity generation and sustainable power generation in the dark. Under visible light illumination, the voltage of the NB-BPV reached a maximum output of 150.6 ± 0.7 mV, with a power density of 326.4 μW/m[2] (per electrode surface area). Meanwhile, it could effectively degrade sodium dodecylbenzene sulfonate (DBS), while generating electricity, and the removal rate of DBS and TOC in 36 h was 77.1 % and 53.2 %, respectively. Under sunlight, NB-BPV could also produce electricity steadily in lake and the removal rate of DBS in simulated lake water was 93.7 % (120 h). Visible light significantly affected the performance of NB-BPV mainly through photosynthesis. Photosynthesis of biofilm promoted electricity generation and significantly enhanced the degradation of DBS by promoting electron transfer activity and generating ROS. Compared with biofilm system, the closed-circuit in NB-BPV promoted electron transfer, allowing more efficient degradation of DBS at relatively low level of ROS. Such a novel self-sustainable BPV has the potential to degrade refractory pollutants, and to be used in natural water.

RevDate: 2025-04-15

Romário-Silva D, Franchin M, Bueno-Silva B, et al (2025)

Brazilian Organic Honeydew Reduces In Vitro and In Vivo Periodontal Disease-Related Subgingival Biofilm.

Foods (Basel, Switzerland), 14(6):.

We investigated the antimicrobial properties and effects on bone resorption of Brazilian organic honeydew (OHD) from the Bracatinga tree (Mimosa scabrella Benth.), a rare honey certified with Denomination of Origin, using a periodontal disease model. Antibiofilm activity was assessed using a subgingival biofilm adhered to the Calgary device. Biofilms were treated with OHD, chlorhexidine (0.12%), or a vehicle twice daily for 1 min starting on day 3, at concentrations of 2× and 10× the minimum inhibitory concentration (MIC). We employed a ligature-induced chronic periodontal disease model and challenged it with Porphyromonas gingivalis in C57BL/6 mice. The chemical profile of OHD was analyzed using LC-ESI-IT-MS/MS. Results were evaluated by measuring bone loss and microbial composition of the ligature biofilm through DNA-DNA hybridization. OHD demonstrated significant activity against P. gingivalis (MIC 4%, MBC 6%) and reduced biofilm viability by 80% in vitro. In vivo, OHD decreased microbial populations and decreased bone loss associated with periodontal disease. Chemical analysis identified seven compounds in OHD, including five flavonoids and two lignans. This Brazilian honeydew from the Atlantic Forest exhibits strong antimicrobial properties and potential as a functional food for oral health, offering a promising alternative for the control and prevention of periodontal disease.

RevDate: 2025-04-16

George MA, McGiffin D, Peleg AY, et al (2025)

Nanowire arrays with programmable geometries as a highly effective anti-biofilm surface.

Biofilm, 9:100275.

Biofilm-related microbial infections are the Achilles' heel of many implantable medical devices. Surface patterning with nanostructures in the form of vertically aligned silicon (Si) nanowires (VA-SiNWs) holds promise to prevent these often "incurable" infections. In this study, we fabricated arrays of highly ordered SiNWs varying in three geometric parameters, including height, pitch size, and tip diameter (sharpness). Anti-infective efficacies of fabricated SiNW arrays were assessed against representative laboratory reference bacterial strains, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922, using a modified microwell biofilm assay representing microorganism-implant interactions at a liquid-solid interface. To further understand the role of individual geometric parameters to the SiNW-induced bacterial killing, SiNW arrays with stepwise changes in individual geometric parameters were compared. The force that NWs applied on bacterial cells was mathematically calculated. Our results suggested that NWs with specific geometries were able to kill adherent bacterial cells and prevent further biofilm formation on biomaterial surfaces. Tip diameter and pitch size appeared to be key factors of nanowires predetermining their anti-infectiveness. Mechanistic investigation found that tip diameter and pitch size co-determined the pressure that NWs put on the cell envelope. The most effective anti-infective NWs fabricated in our study (50 nm in tip diameter and 400 nm in pitch size for S. aureus and 50 nm in tip diameter and 800 nm in pitch size for E. coli) put pressures of approximately 2.79 Pa and 8.86 Pa to the cell envelop of S. aureus and E. coli, respectively, and induced cell lyses. In addition, these NWs retained their activities against clinical isolates of S. aureus and E. coli from patients with confirmed device-related infections and showed little toxicity against human fibroblast cells and red blood cells.

RevDate: 2025-04-14

Negi A, Kuo CW, Hazam PK, et al (2025)

Disruption of MRSA Biofilm and Virulence by Deep-Sea Probiotics: Impacts on Energy metabolism and Host Antimicrobial Peptides.

Probiotics and antimicrobial proteins [Epub ahead of print].

Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat to public health due to its resistance to conventional antibiotics and its ability to form robust biofilms on both biotic and abiotic surfaces. In this study, we explore the novel mechanisms by which deep-sea-derived probiotics serve as an alternative strategy to combat MRSA infections. Three promising probiotic candidates, Lactococcus lactis (L25_4) and two strains of Leuconostoc pseudomesenteroides (L25_6 and L25_7), were isolated from ocean water collected at a depth of 312 m off the eastern coast of Taiwan. Each candidate strain demonstrated potent antimicrobial activity, significantly reducing MRSA biofilm formation when applied to pork skin. The strains also improved survival rates in a Galleria mellonella infection model (> 90% survival). Immunomodulatory effects were evident, with marked upregulation of Cecropin antimicrobial peptide (AMP) and downregulation of Gloverin AMP in the host. Scanning and transmission electron microscopy (SEM and TEM) revealed that probiotic treatments compromised MRSA cell membrane integrity, consistent with transcriptomic analysis showing downregulation of genes related to protein translation, membrane structure, and transporter systems. Collectively, our comprehensive in vitro, in vivo, ex vivo, and transcriptomic analyses reveal the intricate mechanisms by which deep-sea probiotics modulate both host and MRSA gene expression, underscoring their potential as innovative tools for addressing antibiotic-resistant infections.

RevDate: 2025-04-14

García-García P, Évora C, Delgado A, et al (2025)

Chitosan-aloe vera scaffolds with tuned extracellular vesicles and histatin-5 display osteogenic and anti-biofilm activities.

International journal of pharmaceutics pii:S0378-5173(25)00429-6 [Epub ahead of print].

The use of extracellular vesicles (EVs) has garnered significant attention as an alternative to cell-based therapies due to their stability and biocompatibility. In this study, we stimulated mesenchymal stem cells (MSCs) with therapeutic agents affecting the bone regenerative cascade, including bone morphogenetic protein 2 (BMP-2), stromal-derived factor (SDF-1), interleukin 4 (IL-4), alendronate (ALD) and osteogenic differentiation media to obtain osteogenic EVs. The tuned EVs were tested on MSCs and fibroblasts, selecting EVs-BMP2 as suitable systems. Chitosan-aloe vera (AV) scaffolds were designed to allow for the loading and release of these EVs while leveraging the antibacterial and anti-inflammatory properties of AV. To enhance the dual effect on regeneration and antibacterial activity, poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating Histatin 5 (Hist-5) were incorporated to the scaffolds. Hist-5 encapsulation was successful, and effectively prevented Staphylococcus aureus biofilm formation on the scaffolds surface. The optimized chitosan-AV scaffolds loaded with EVs-BMP-2 promoted MSCs adhesion and proliferation and exhibited a 2-fold increase in osteogenic differentiation compared to chitosan scaffolds. This study demonstrates the successful combination of bioengineered EVs and Hist-5-loaded microspheres within a chitosan-AV scaffold, providing a promising dual approach for enhancing bone regeneration while reducing the risk of infection. These systems show potential as effective implants for bone fractures, offering both antibacterial and regenerative capabilities.

RevDate: 2025-04-14

Fu Y, Wang J, X Wang (2025)

Simulation of head-tail biofilm streamer growth based on immersed boundary method.

Biofouling [Epub ahead of print].

Biofilms are subjected to various forces in the fluid field, as a result, the biofilm forms a head-tail structure known as a streamer to reduce pressure differential resistance. To characterize biofilm growth in fluid, we establish a head-tail biofilm streamer growth model based on the immersed boundary method using MATLAB software, and simulate streamer growth in various environmental conditions to explore the factors affecting its growth. Firstly, we found that a higher flow velocity makes the streamer grow faster and thereby produce more biomass. Secondly, we explored the effect of the position of nutrient source on the streamer growth, found that when the nutrient source overlaps with the streamer, its length is longer than when the nutrient source and the streamer are mismatched. Further we found that the Young's modulus of the streamer also influences its growth length. Streamers with small Young's modulus were more likely to deform, making them grow longer than the streamers with large Young's modulus. Finally, we determined the relationship between the tail length and the head diameter of the streamer through mechanical analysis, and found that there is an optimal ratio of the tail length to the head diameter which exposes the streamer to the minimum drag in the fluid field.

RevDate: 2025-04-16
CmpDate: 2025-04-13

Hakim TA, Zaki BM, Mohamed DA, et al (2025)

Novel strategies for vancomycin-resistant Enterococcus faecalis biofilm control: bacteriophage (vB_EfaS_ZC1), propolis, and their combined effects in an ex vivo endodontic model.

Annals of clinical microbiology and antimicrobials, 24(1):24.

BACKGROUND: Endodontic treatment failures are predominantly attributed to Enterococcus faecalis (E. faecalis) infection, a Gram-positive coccus. E. faecalis forms biofilms, resist multiple antibiotics, and can withstand endodontic disinfection protocols. Vancomycin-resistant strains, in particular, are challenging to treat and are associated with serious medical complications.

METHODS: A novel phage, vB_EfaS_ZC1, was isolated and characterized. Its lytic activity against E. faecalis was assessed in vitro through time-killing and biofilm assays. The phage's stability under various conditions was determined. Genomic analysis was conducted to characterize the phage and its virulence. The phage, propolis, and their combination were evaluated as an intracanal irrigation solution against a 4-week E. faecalis mature biofilm, using an ex vivo infected human dentin model. The antibiofilm activity was analyzed using a colony-forming unit assay, field emission scanning electron microscopy, and confocal laser scanning microscopy.

RESULTS: The isolated phage, vB_EfaS_ZC1, a siphovirus with prolate capsid, exhibited strong lytic activity against Vancomycin-resistant strains. In vitro assays indicated its effectiveness in inhibiting planktonic growth and disrupting mature biofilms. The phage remained stable under wide range of temperatures (- 80 to 60 °C), tolerated pH levels from 4 to 11; however the phage viability significantly reduced after UV exposure. Genomic analysis strongly suggests the phage's virulence and suitability for therapeutic applications; neither lysogeny markers nor antibiotic resistance markers were identified. Phylogenetic analysis clustered vB_EfaS_ZC1 within the genus Saphexavirus. The phage, both alone and in combination with propolis, demonstrated potent antibiofilm effects compared to conventional root canal irrigation.

CONCLUSION: Phage vB_EfaS_ZC1 demonstrates a promising therapy, either individually or in combination with propolis, for addressing challenging endodontic infections caused by E. faecalis.

RevDate: 2025-04-13

Jing K, Li Y, Li Y, et al (2025)

The treated wastewater enhances the biodegradation of sulfonamide antibiotics in biofilm-sediment downstream of the receiving river outlet.

Environmental research pii:S0013-9351(25)00851-5 [Epub ahead of print].

Although the treated wastewater meets the discharge standards, it can still become a potential transmitted stressor that affects aquatic organisms in receiving rivers. Biofilms and sediments as the main solid-phase substances in natural aquatic environments can biodegrade micropollutants. However, most of the current studies have selected a single solid-phase material, and there are relatively few studies that comprehensively consider the effect of treated wastewater on the dissipation of micropollutants in a composite biofilm-sediment system. Therefore, this study investigated the dissipation pathways of six sulfonamide antibiotics (SAs) in biofilm-sediment and the effect of treated wastewater on SAs dissipation. The results showed that biodegradation was the main pathway for SAs dissipation in biofilm-sediment. The input of treated wastewater increased the abundance of dominant degradation bacteria Burkholderiales and Pseudomonadale, thereby improving the biodegradation rate of SAs (approximately 1.5 times higher than upstream degradation rate). These genera could also be further integrated into downstream communities to continuously mediate the biodegradation of SAs. Through mass spectrometry and metagenomic sequencing analysis, it was found that the common degradation pathways of SAs in biofilm-sediment affected by treated wastewater are acetylation, formylation, hydroxylation, and bond cleavage. Acetyltransferase played an important role in the biodegradation of SAs. In addition, the enrichment of antibiotic resistant genes during biodegradation increased the risk of their spread in the aquatic environment. These findings provide new insights into the fate of antibiotics in aquatic environments and the impact of treated wastewater on downstream bacterial communities.

RevDate: 2025-04-13

Yan X, Tao R, Zhou H, et al (2025)

Sublethal sanitizers exposure differentially affects biofilm formation in three adapted Salmonella strains: A phenotypic-transcriptomic analysis of increased biofilm formed by ATCC 14028.

International journal of food microbiology, 436:111189 pii:S0168-1605(25)00134-5 [Epub ahead of print].

PURPOSE: Using sanitizer in food industry is an important mean of sterilization and biofilm eradication, but inappropriate operation may lead to resistance, posing a concealed risk to food safety. The purpose of this study was to assess the impact of sub-lethal sanitizers on the biofilm formed by adaptive Salmonella and to explore the variations in transcription within adaptive Salmonella biofilms when co-incubated with sublethal concentrations of sanitizers.

METHODS: The microbroth dilution method was determined to measure the MIC of three sanitizers on Salmonella, and adaptation induction was conducted with steadily increasing sanitizer concentrations. The effect of sub-MIC sanitizers on the biofilm of Salmonella was investigated by crystal violet method, confocal laser scanning microscopy and transcriptomics.

RESULTS: The results indicated that the maximum growth concentration of the adapted strains was 1.69-43.25 times that of the original MIC, and the number of bacteria and matrix content were increased when re-exposed to sub-MIC benzalkonium chloride (BZK), and the expression of regulatory factors and various amino acid biosynthesis and metabolism-related genes showed an up-regulation trend.

SIGNIFICANCE: This will be beneficial to clarify the correlation and mechanism between the sanitizer adaptation of salmonellae caused by improper sanitization and increased biofilm formation resulting from this adaptation. And it helps to adjust the appropriate dosage of sanitizer and optimize sanitation standard operating procedures (SSOP) in the foodstuff industry, thereby effectively promoting the bactericidal effect and eliminating foodborne pathogens' biofilm.

RevDate: 2025-04-15
CmpDate: 2025-04-12

Rahim S, Rahman R, Jhuma TA, et al (2025)

Disrupting antimicrobial resistance: unveiling the potential of vitamin C in combating biofilm formation in drug-resistant bacteria.

BMC microbiology, 25(1):212.

BACKGROUND: Antimicrobial resistance (AMR) poses a significant threat to global health, exacerbated by the protective mechanisms of biofilms formed by drug-resistant bacteria. Extracellular polymeric substances (EPS) produced by bacteria in biofilms serve as a formidable shield, impeding the efficacy of antimicrobial agents. Here, we investigated the potential of vitamin C (sodium ascorbate) to disrupt biofilm formation in drug-resistant bacteria isolated from diabetic foot ulcer (DFU) patients and studied the antimicrobial and antibiofilm activity of vitamin C on these bacteria.

RESULTS: Out of 117 study isolates, primarily identified as Escherichia coli (n = 52), Staphylococcus spp. (n = 19), and Klebsiella spp. (n = 46), 80 isolates exhibited a Multiple Antimicrobial Resistance (MAR) index greater than 0.2, classifying them as multi-drug resistant (MDR) superbugs. Among these, 58 isolates demonstrated moderate to strong biofilm-forming abilities and were selected for further experiments with vitamin C. The effective concentration of vitamin C inhibiting the growth of most E. coli and Klebsiella spp. isolates (90%) was estimated at 1.25 mg/ml and 2.5 mg/ml respectively, while for allStaphylococcus spp. isolates, it was 0.325 mg/ml. Vitamin C exhibited a notable anti-biofilm effect against the studied isolates, with biofilm prevention concentrations (BPC) of 0.625, 1.25, and 0.16 mg/ml for E. coli, Klebsiella spp., and Staphylococcus spp. isolates respectively. Furthermore, when combined with oxacillin or amoxicillin - drugs that were found ineffective, vitamin C significantly reduced the ability of MDR isolates to form biofilms, rendering them susceptible to the drugs' effects and restoring their efficacy. The expression of the recA gene, an early and quantifiable marker for the onset of the SOS response and biofilm production was downregulated after treatment of E. coli with vitamin C. Relative gene expression analysis revealed that ciprofloxacin-induced recA expression was significantly inhibited when MDR isolates of E. coli were treated with vitamin C at a concentration of 0.625 mg/ml, the BPC of vitamin C.

CONCLUSION: Our findings reveal that vitamin C, alone or in combination with ineffective antibiotics, attenuates biofilm formation and restores the susceptibility of multidrug-resistant (MDR) isolates to antimicrobial agents. This study underscores the promise of vitamin C as a non-lethal disruptor of biofilm-associated antimicrobial resistance.

CLINICAL TRIAL NUMBER: Not applicable.

RevDate: 2025-04-15

Pérez AR, Rendón J, Ortolani-Seltenerich PS, et al (2025)

Extraradicular Infection and Apical Mineralized Biofilm: A Systematic Review of Published Case Reports.

Journal of clinical medicine, 14(7):.

Background/Objectives: Bacterial biofilms on root surfaces outside the apical foramen are linked to refractory apical periodontitis, as microorganisms can survive in extraradicular areas and cause persistent infections. This study aimed to precisely evaluate the relationship between extraradicular biofilm and persistent periapical periodontitis through an overview of case reports. Methods: A systematic search of PubMed, Web of Science, Scopus, Embase and ScienceDirect databases was conducted up to June 2023. Keywords included "extraradicular infection", "wet canal", "wet canals", "extraradicular mineralized biofilms", and "calculus-like deposit". Only case reports meeting the inclusion criteria were analyzed. Results: Fifteen cases of extraradicular infection were identified, involving eight women and six men aged between 18 and 60 years. These cases included nine failed treatments confirmed through complementary methods such as histobacteriologic analysis, scanning electron microscopy (SEM), or polymerase chain reaction (PCR). Among these, four patients (six teeth) exhibited calculus-like deposits. Conclusions: Extraradicular biofilm is strongly associated with failed endodontic treatments, leading to persistent infections. A structured decision-making approach is essential. Before considering apical surgery, clinicians should prioritize intraradicular infection control through thorough irrigation, antimicrobial medicaments, and adjunctive disinfection techniques. When extraradicular biofilms or mineralized calculus are present, and symptoms persist after optimal intracanal disinfection, apical surgery should be performed.

RevDate: 2025-04-14
CmpDate: 2025-04-11

Pizzi F, Peters F, Sorribes E, et al (2025)

Modulation of biofilm growth by shear and fluctuations in turbulent environments.

Scientific reports, 15(1):12460.

This work investigates the role of shear and turbulent fluctuations on multi-species biofilm growth. The study is mostly motivated by understanding biofouling on microplastics (MPs) in oceanic environments. By increasing particle stickiness, biofilms promote MP aggregation and sinking; therefore, a thorough understanding of this multi-scale process is crucial to improve predictions of the MPs fate. We conducted a series of laboratory experiments using an oscillating-grid system to promote biofilm growth on small plastic surfaces under homogeneous isotropic turbulence with grid Reynolds numbers between 305 and 2220. Two configurations were analyzed: one where plastic samples move along with the grid (shear-dominated) and another one where the samples are kept fixed downstream the grid, thus experiencing turbulence but no mean flow (shear-free). Biofilm formed in all cases in a time scale of days, then the biomass formed on the plastic pieces was carefully measured and analyzed as a function of the turbulence level. The shear-free results were further interpreted using a parsimonious physical model, coupling the nutrient uptake rate within the biofilm (Monod kinetics) with the turbulent diffusion of the surrounding bulk liquid. Results show that: (i) under shear-dominated conditions, the biofilm mass initially grows with turbulence intensity before decaying, presumably due to shear-induced erosion; (ii) in the shear-free experiments, the mass increases monotonically following an enhanced availability of nutrients, and then saturates due to uptake-limited kinetics. This latter behavior is well reproduced by the physical model. Furthermore, a subset of plastic pieces were analyzed with a scanning electron microscope, revealing that turbulence also affects the microscopic configuration of biofilm clusters, increasing their compactness as the amplitude of turbulent fluctuations increases. These results contribute not only to our fundamental understanding of biofilms under flow, but can also inform global models of MP transport in marine environments.

RevDate: 2025-04-14
CmpDate: 2025-04-11

Huttunen KL, Malazarte J, Jyväsjärvi J, et al (2025)

Temporal Beta Diversity of Bacteria in Streams: Network Position Matters But Differently for Bacterioplankton and Biofilm Communities.

Microbial ecology, 88(1):26.

Concern about biodiversity loss has yielded a surge of studies on temporal change in α-diversity, whereas temporal β-diversity has gained less interest. We sampled bacterioplankton, biofilm, and riparian soil bacteria repeatedly across the open-water season in a pristine stream network to determine the level of temporal β-diversity in relation to stream network position and environmental variability. We tested the hypothesis that aquatic bacterial communities in isolated and environmentally heterogenous headwaters exhibit high temporal β-diversity while the better-connected and environmentally more stable mainstem sections support more stable communities, and soil communities bear no relationship to network position. As expected, temporal β-diversity decreased from headwaters toward mainstems for bacterioplankton. Against expectations, an opposite pattern was observed for biofilm. For bacterioplankton, temporal β-diversity was positively related to temporal variability in water chemistry. For biofilm bacteria, temporal variability was negatively related to variability in temperature. Temporal β-diversity of soil communities did not show any response to stream network position, but was strongly related to variability in the soil environment. The two aquatic habitats and riparian soils supported distinctly different bacterial communities. The number of ASVs shared between the soil and the aquatic communities decreased along the network, and more so for bacterioplankton. The higher temporal variability of bacterial communities in the headwaters likely results from temporally variable input of propagules from riparian soil, emphasizing the role of land-water connection and network position to bacterioplankton community composition. Overall, bacterial communities exhibited high temporal variability, highlighting the importance of temporal replication to fully capture their network-scale biodiversity.

RevDate: 2025-04-12

Yi S, Liu Y, Wu Q, et al (2025)

Glycosylation of oral bacteria in modulating adhesion and biofilm formation.

Journal of oral microbiology, 17(1):2486650.

BACKGROUND: Glycosylation is a ubiquitous biochemical process that covalently attaches glycans to proteins or lipids, which plays a pivotal role in modulating the structure and function of these biomolecules. This post-translational modification is prevalent in living organisms and intricately regulates various biological processes, including signaling transduction, recognition, and immune responses. In the oral environment, bacteria ingeniously use glycosylation to enhance their adhesion to oral surfaces, which is a key step in biofilm formation and subsequent development. This adhesion process is intimately associated with the onset and progression of oral diseases, including dental caries and periodontal disease.

OBJECTIVE: This review aims to describe the types and mechanisms of glycosylation in oral bacteria, and to understand the role of glycosylation in the adhesion, biofilm formation and virulence of oral bacteria.

METHODS: We reviewed articles on glycosylation in a variety of oral bacteria.

CONCLUSION: In cariogenic bacteria and periodontopathic pathogens, glycosylation facilitates adhesion and subsequent biofilm maturation on tooth surface.   Distinct glycosylation patterns in oral bacteria shape biofilm structure and function, influencing microbial interactions and community stability.   Pathogen-specific glycosylation signatures enhance virulence and ecological competitiveness, contributing to disease progression. Glycosylation plays a critical role in bacterial virulence and community  interactions, with significant implications for oral health and disease development.

RevDate: 2025-04-12

Muratov E, Keilholz J, Kovács ÁT, et al (2025)

The biofilm matrix protects Bacillu subtilis against hydrogen peroxide.

Biofilm, 9:100274.

Biofilms formed by Bacillus subtilis confer protection against environmental stressors through extracellular polysaccharides (EPS) and sporulation. This study investigates the roles of these biofilm components in resistance to hydrogen peroxide, a common reactive oxygen species source and disinfectant. Using wild-type and mutant strains deficient in EPS or sporulation, biofilm colonies were cultivated at various maturation stages and exposed to hydrogen peroxide. EPS-deficient biofilms exhibited reduced resilience, particularly in early stages, highlighting the structural and protective importance of the matrix. Mature biofilms demonstrated additional protective mechanisms, potentially involving TasA protein fibers and/or the biofilm surface layer (BslA). In contrast, sporulation showed limited contribution to hydrogen peroxide resistance, as survival was primarily matrix-dependent. These findings underscore the necessity of targeting EPS and other matrix components in anti-biofilm strategies, suggesting that hydrogen peroxide-based disinfection could be enhanced by combining it with complementary sporicidal treatments. This study advances our understanding of biofilm resilience, contributing to the development of more effective sterilization protocols.

RevDate: 2025-04-12

Amador CI, Røder HL, Herschend J, et al (2025)

Decoding the impact of interspecies interactions on biofilm matrix components.

Biofilm, 9:100271.

Multispecies biofilms are complex communities where extracellular polymeric substances (EPS) shape structure, adaptability, and functionality. However, characterizing the components of EPS, particularly glycans and proteins, remains a challenge due to the diverse bacterial species present and their interactions within the matrix. This study examined how interactions between different species affect EPS component composition and spatial organization. We analyzed a consortium of four bacterial soil isolates that have previously demonstrated various intrinsic properties in biofilm communities: Microbacterium oxydans, Paenibacillus amylolyticus, Stenotrophomonas rhizophila, and Xanthomonas retroflexus. We used fluorescence lectin binding analysis to identify specific glycan components and meta-proteomics to characterize matrix proteins in mono- and multispecies biofilms. Our results revealed diverse glycan structures and composition, including fucose and different amino sugar-containing polymers, with substantial differences between monospecies and multispecies biofilms. In isolation, M. oxydans produced galactose/N-Acetylgalactosamine network-like structures and influenced the matrix composition in multispecies biofilms. Proteomic analysis revealed presence of flagellin proteins in X. retroflexus and P. amylolyticus, particularly in multispecies biofilms. Additionally, surface-layer proteins and a unique peroxidase were identified in P. amylolyticus multispecies biofilms, indicating enhanced oxidative stress resistance and structural stability under these conditions. This study highlights the crucial role of interspecies interactions in shaping the biofilm matrix, as well as the production of glycans and proteins, thereby enhancing our understanding of biofilm complexity.

RevDate: 2025-04-12

Xu M, Wang X, Gong T, et al (2025)

Glucosyltransferase activity-based screening identifies tannic acid as an inhibitor of Streptococcus mutans biofilm.

Frontiers in microbiology, 16:1555497.

Dental caries is a biofilm-related chronic infectious disease. Streptococcus mutans is the core microorganism that leads to caries, with its capacity to form biofilms via glucosyltransferases (Gtfs) being the predominant virulence factor contributing to this condition. Therefore, researching novel drugs targeting Gtf is important for treating dental caries. Our study established a rapid detection method for Gtf activity to screen over 1,000 compounds from the Selleck Natural Product Library. We identified tannic acid (TA) as a potential inhibitor of Gtf activity. In vitro experiments suggested that TA could inhibit extracellular polysaccharide (EPS) synthesis and biofilm formation in S. mutans by selectively antagonizing Gtf rather than directly killing the bacteria. Molecular docking experiments confirmed a strong binding affinity between TA and Gtf. In summary, TA exhibits good anti-virulence performance against S. mutans, indicating its potential value in anti-biofilm and anti-caries applications.

RevDate: 2025-04-12

Díaz-Navarro M, Irigoyen-von-Sierakowski Á, Delcán I, et al (2025)

New insights in the role of Candida biofilm in the pathogenesis of recurrent vulvovaginal candidiasis: a prospective clinical study.

Frontiers in microbiology, 16:1566171.

BACKGROUND: Despite the pathogenesis of vulvovaginal candidiasis (VVC) is multifactorial, this study aimed to assess whether phenotypic characteristics, such as biofilm production and quality, along with clinical symptoms, are associated with recurrent VVC (RVVC).

METHODS: Over 1 year (Oct 2021-Oct 2022), we prospectively included 271 patients ≥18 years who attended our institution, had Candida spp. isolated in vaginal swabs, and provided informed consent. Patients were followed for 1 year. Candida spp. isolates were tested by the following techniques: crystal violet (CV) for biomass quantification, XTT for metabolic activity quantification, and microscopy for biofilm area quantification. Clinical and microbiological data were also collected.

RESULTS: Overall, 55 (20.3%) patients experienced at least one recurrence, with 19 (7.0%) meeting the criteria for RVVC (≥3 episodes/year), with 65 episodes in total. Demographic and clinical characteristics were similar in both study groups. Most isolates were C. albicans (90.0%). Median (interquartile, [IQR]) absorbance values for CV and XTT in 18/19 RVVC and 238/252 non-RVVC isolates were as follows: CV, 1.850 (1.578-2.156) vs. 1.426 (1.081-1.823), p = 0.005; XTT, 0.184 (0.116-0.293) vs. 0.228 (0.147-0.331), p = 0.253. Median (IQR) biofilm occupation area percentage in 16/19 RVVC and 16/252 non-RVVC isolates was, respectively: 13.15 (8.54-16.9) and 10.73 (5.88-17.73), p = 0.710.

CONCLUSION: RVVC was associated to high biomass production. Additionally, RVVC clinical isolates exhibited a tendency toward lower metabolic activity, which may contribute to treatment failure.

RevDate: 2025-04-12

Sowmya KP, Surenthar M, V Lekha Sree (2025)

Effective treatment of oral microbial infections and biofilm using flavonoid rutin - An in vitro study.

Journal of oral biology and craniofacial research, 15(3):541-547.

BACKGROUND: Oral microbial infections and biofilm-associated conditions, such as dental caries, gingivitis, and periodontitis, remain major challenges in oral healthcare. Biofilms provide resistance to conventional antimicrobial treatments, necessitating innovative solutions. This study investigates rutin, a flavonoid glycoside, for its antimicrobial and antibiofilm properties against key oral pathogens.

AIM: To evaluate the antibacterial and antibiofilm efficacy of rutin against oral pathogens, including Streptococcus mutans, Pseudomonas aeruginosa, and Candida albicans, and assess its hemocompatibility as a safe therapeutic agent.

METHODOLOGY: Oral pathogens were isolated from clinical samples and identified using the VITEK®2 Compact System. Antimicrobial activity of five flavonoids was screened using the well diffusion method, with rutin demonstrating the highest efficacy. Minimum inhibitory concentration (MIC) and antibiofilm activity were assessed using broth microdilution and crystal violet staining, respectively. Confocal Laser Scanning Microscopy analyzed live/dead cells in treated biofilms. Hemocompatibility was evaluated via a hemolysis assay.

RESULTS: Rutin exhibited significant antimicrobial activity with zone of inhibition as 19 mm (C. albicans), 17 mm (P. aeruginosa), and 17 mm (S. mutans). MIC against mixed biofilms was 10 mM, while treatment at 2 × MIC reduced biofilm biomass by 92 %. Live/dead analysis confirmed extensive microbial cell death in biofilms. Hemolysis rates below 5 % established rutin's biocompatibility.

CONCLUSION: Rutin demonstrates potent antimicrobial and antibiofilm efficacy with excellent safety, suggesting its potential as an alternative therapy for biofilm-associated oral infections. Further in vivo studies are warranted to validate these findings.

RevDate: 2025-04-10

Ahmed ME, Aljarbou A, Mohammed HA, et al (2025)

Bacteriocin Isolated from Ralstonia mannitolilytica and Bacteriocin-Capped Silver Nanoparticles: Comparative Effects on Biofilm Formation and LuxS Gene's Expressions by Proteus mirabilis as an Approach to Counter MDR Catheter Infection.

Microbial pathogenesis pii:S0882-4010(25)00283-9 [Epub ahead of print].

Among undesirable situation in treating certain infections and diseases is the contamination of catheters, especially with the microbes' resistance to drugs. The situation has necessitated the search for alternative antimicrobial agents. Bacteriocin category, antibiotic originate, peptide-natured, Ralstonia mannitolilytica microbes-produced, bacteriocin material, and the semi-pure bacteriocin capped silver metal nanoparticles (AgNPs) were used for combating the MDR (multi drug resistance) organism, Proteus mirabilis, which is the third-most common cause of UTI (urinary tract infection), and that is linked to catheter use, are being recommended for clinical use with certain development. The crude microbial product was isolated from the microbial entity, Ralstonia mannitolilytica, which grows in crude petroleum-contaminated soil, and was semi-purified for use in the synthesis of the bacteriocin-capped AgNPs. The prepared nanoparticles were characterized using X-ray diffraction, indicating the silver element's presence; field emission scanning electron microscopy, revealing near-spherical but irregular shapes of the bacteriocin-capped AgNPs with a size range of 34-46 nm; and atomic force microscopic analysis, which demonstrated the nanoparticles surface characteristics. The DLS analysis established the negative charge, and an average hydrodynamic size of 51 nm, while the UV-Vis spectroscopic analysis showed the absorption maxima (λmax) at 454 nm. The P. mirabilis isolates were numbered according to MDR detection by the VITEK 2 system (A to J), and the microbes appeared as a pale-coloured colony on MacConkey agar. The biofilm formation screening revealed the highest biofilm-producing isolates, termed as A, B, C, and D. The treatments with both bacteriocin and the bacteriocin-capped AgNPs showed that bacteriocin effectively inhibited the biofilm formation for isolates A, B, and C, but isolate D was less affected. In addition, the LuxS gene-down-regulating effects of bacteriocin and bacteriocin-capped AgNPs were also observed. The expression of the LuxS gene in P. mirabilis was lowered by bacteriocin-capped AgNPs during biofilm formation, while the isolates B and C lowered their expressions of the LuxS gene more effectively when the bacteriocin was used.Conversely, the study recommends the use of bacteriocin-capped AgNPs for controlling and treating the possible catheter infection, which needs further development as a product and established clinical testing.

RevDate: 2025-04-10

Sonu PK, Srivastav AK, Anjali , et al (2025)

Extraction and physiochemical characterization of micro-fibrillated cellulose based composite biofilm derived from Aegle marmelos fruit shells waste for packaging applications supported by in-silico docking studies.

International journal of biological macromolecules pii:S0141-8130(25)03473-7 [Epub ahead of print].

The utilization of waste shells from Aegle marmelos (bael) as a source of Micro fibrillated cellulose (MFC) was undertaken for applications in food packaging within the framework of this investigation. FTIR analysis of CAM and Raw Aegle marmelos shell powder (RAM) showed stretching of -OH and -CH groups at 3339 cm[-1] and 2889 cm-[1]. Our results showed that crystallinity indices of CAM and RAM were 39.59 % and 18.89 %, respectively indicating a significant raise in crystallinity after extraction. FTIR analysis reveals the presence of hydroxyl groups (3306 cm[-1]) in all films. Exploration of the results indicated the development of covalent and H (hydrogen) bonds between CAM and Guar gum/Chitosan (GT), as discerned through FT-IR studies. X-ray diffraction unveiled in the amorphous feature of the films following CAM into GT composite film. Evaluation through FE-SEM exhibited a densely disordered network contributing to a heightened contact angle of the resultant film with an enhanced concentration of CAM. Cellulose Iβ and Chitosan showed stronger binding affinity of -7.3 kcal/mol, suggesting greater compatibility and stability. The antioxidant capacity of the films increased from 10.90 to 61.80 due to addition of CAM in the GT mixture where elevated concentrations demonstrated better scavenging activity.

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.

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ESP Quick Facts

ESP Origins

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.

ESP Support

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

ESP Rationale

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

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

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Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

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When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

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

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

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Papers in Classical Genetics

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

Digital Books

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

Timelines

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

Biographies

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

Selected Bibliographies

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

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