Biofilm最新文献

{"title":"Small cyclic dipeptide produced by Lactobacillus rhamnosus with anti-biofilm properties against Streptococcus mutans biofilm","authors":"Rashmi Niranjan ,&nbsp;Sachin Patil ,&nbsp;Amrita Dubey ,&nbsp;Bimlesh Lochab ,&nbsp;Richa Priyadarshini","doi":"10.1016/j.bioflm.2024.100237","DOIUrl":"10.1016/j.bioflm.2024.100237","url":null,"abstract":"<div><div>The human oral cavity harbors many bacterial species collectively termed the oral microbiome and is integral for maintaining oral health. Dysbiosis of oral microbiota leads to common oral diseases, including dental caries, gingivitis, and periodontitis. <em>Streptococcus mutans</em> is the primary causative agent of dental caries. Studies have explored the use of probiotic <em>Lactobacillus</em> spp. to mitigate <em>S. mutans</em> biofilms. In the present study, we have tested the use of <em>Lactobacillus rhamnosus</em> extracts/metabolites for anti-biofilm properties. A small organic compound/metabolite was isolated from the cell-free supernatant of <em>L. rhamnosus</em>, and this metabolite resulted in a dose-dependent inhibition of <em>S. mutans</em> biofilms. Confocal microscopy revealed that the thickness of <em>S. mutans</em> biofilms was severely reduced upon metabolite treatment. With the help of FTIR spectra and mass spectrometry analysis, the molecular formula (C₁₁H₁₉O₂N₂) was deduced. The inhibitor compound was further identified as a small cyclic peptide, cyclo (-L-Leu-L-Pro). Our data also revealed that isolated metabolite impedes <em>S. mutans</em> biofilms by modulating gene expression of several essential genes involved in biofilm establishment.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100237"},"PeriodicalIF":5.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization of gliotoxin synthesis in a biofilm model of Aspergillus fumigatus","authors":"Alicia Gomez-Lopez ,&nbsp;Candela Fernandez-Fernandez","doi":"10.1016/j.bioflm.2024.100238","DOIUrl":"10.1016/j.bioflm.2024.100238","url":null,"abstract":"<div><div>Mycelial growth as biofilm structures and the activation of secondary metabolism leading to the release of low-molecular-weight molecules (known as secondary metabolites), are among the previously described strategies used by the filamentous fungi <em>Aspergillus fumigatus</em> to adapt and survive. Our study unveils that <em>A. fumigatus</em> strains can activate mechanisms linked to the production of gliotoxin, a crucial metabolite for <em>Aspergillus</em>, in the established <em>in vitro</em> biofilm model. Gliotoxin production exhibits strain- and time-dependent patterns and is associated -in a coordinated manner-with the expression levels of several genes involved in its regulation and synthesis. The transcriptional study of some of these genes by qPCR shows temporal inter-strain differences, which correlate with those obtained when evaluating the amounts of metabolites produced. Given that <em>A. fumigatus</em> forms biofilm structures within the site of infection, understanding the regulation of gliotoxin biosynthesis may have a role in the evolution of <em>Aspergillus</em> infection and guide diagnostic and treatment strategies.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100238"},"PeriodicalIF":5.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcatheter aortic valve implantation (TAVI) prostheses in vitro - biofilm formation and antibiotic effects","authors":"Torgny Sunnerhagen ,&nbsp;Thomas Bjarnsholt ,&nbsp;Klaus Qvortrup ,&nbsp;Henning Bundgaard ,&nbsp;Claus Moser","doi":"10.1016/j.bioflm.2024.100236","DOIUrl":"10.1016/j.bioflm.2024.100236","url":null,"abstract":"<div><h3>Background</h3><div>Transcatheter aortic valve implantation (TAVI) is a percutaneous catheter-based treatment of aortic stenosis as an alternative to open heart valve surgery. In cases of TAVI endocarditis, the treatment possibilities may be limited as surgical removal of the infected valve may be associated with a high risk in elderly, comorbid or frail patients. The propensity of bacteria to form a biofilm on foreign material is assumed to be of importance part of the disease process in TAVI endocarditis, but no studies on biofilm formation on TAVI valves have been conducted. We hypothesize that <em>Staphylococcus aureus</em> and <em>Enterococcus faecalis</em> biofilm formation on TAVI valves may have an impact on antibiotic tolerance and non-surgical cure rates.</div></div><div><h3>Methods</h3><div>TAVI valves (pieces including part of the metal frame, approximately 1 cm wide) were exposed to either species <em>in vitro</em> in LB-Krebs Ringer medium at 37 °C, with the bacterial count being assessed by culturing of sonicated TAVI pieces and broth at 0, 4, 18 and 24 h after bacterial exposure. Scanning electron microscopy (SEM) was performed. Effects of ampicillin, gentamicin, moxifloxacin, rifampicin (for <em>S. aureus</em>), and ceftriaxone (for <em>E. faecalis</em>) at 5 times minimal inhibitory concentration were tested alone and in combination with ampicillin. Antibiotics were added to biofilm aged 0 or 24 h and the effects assessed.</div></div><div><h3>Results</h3><div>Exposure for 15 min established attachment to all of valve pieces. SEM findings were consistent with biofilm formation and suggested lower amounts of bacteria on the metal compared to the tissue part of the TAVI valves. The number of bacteria attached to the TAVI valves increased until 24 h of incubation from less than 10^1 to a level of approximately 10^9 CFU/g. The bacteria became more tolerant to antibiotics on the TAVI valves over time, with the bactericidal effect against 24-h old biofilm being significantly less effective than against 0-h old biofilm depending on antibiotic.</div></div><div><h3>Conclusions</h3><div>The results indicate that bacteria can adhere to metal and tissue parts of the TAVI valves within minutes after an exposure which is comparable to transient bacteremia <em>in vivo</em>, and that the bacteria rapidly gain biofilm properties, associated with significantly reduced antibiotic effect.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100236"},"PeriodicalIF":5.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of nanoparticles on anaerobic, anammox, aerobic, and algal-bacterial granular sludge: A comprehensive review","authors":"Alfonz Kedves ,&nbsp;Zoltán Kónya","doi":"10.1016/j.bioflm.2024.100234","DOIUrl":"10.1016/j.bioflm.2024.100234","url":null,"abstract":"<div><div>Nanoparticles (NPs) are of significant interest due to their unique properties, such as large surface area and high reactivity, which have facilitated advancements in various fields. However, their increased use raises concerns about environmental impacts, including on wastewater treatment processes. This review examines the effects of different nanoparticles on anaerobic, anammox, aerobic, and algal-bacterial granular sludge used in wastewater treatment. CeO₂ and Ag NPs demonstrated adverse effects on aerobic granular sludge (AGS), reducing nutrient removal and cellular function, while anaerobic granular sludge (AnGS) and anammox granular sludge (AxGS) showed greater resilience due to their higher extracellular polymeric substance (EPS) content. TiO₂ NPs had fewer negative effects on algal-bacterial granular sludge (ABGS) than on AGS, as algae played a crucial role in enhancing EPS production and stabilizing the granules. The addition of Fe₃O₄ NPs significantly enhanced both aerobic and anammox granulation by reducing granulation time, promoting microbial interactions, improving granule stability, and increasing nitrogen removal efficiency, primarily through increased EPS production and enzyme activity. However, Cu and CuO NPs exhibited strong inhibitory effects on aerobic, anammox, and anaerobic systems, affecting EPS structure, cellular integrity, and microbial viability. ZnO NPs demonstrated dose-dependent toxicity, with higher concentrations inducing oxidative stress and reducing performance in AGS and AnGS, whereas AxGS and ABGS were more tolerant due to enhanced EPS production and algae-mediated protection. The existing knowledge gaps and directions for future research on NPs are identified and discussed.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100234"},"PeriodicalIF":5.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relaxation-weighted MRI analysis of biofilm EPS: Differentiating biopolymers, cells, and water","authors":"Matthew R. Willett ,&nbsp;Sarah L. Codd ,&nbsp;Joseph D. Seymour ,&nbsp;Catherine M. Kirkland","doi":"10.1016/j.bioflm.2024.100235","DOIUrl":"10.1016/j.bioflm.2024.100235","url":null,"abstract":"<div><div>Biofilms are a highly complex community of microorganisms embedded in a protective extracellular polymeric substance (EPS). Successful biofilm control requires a variety of approaches to better understand the structure-function relationship of the EPS matrix. Magnetic resonance imaging (MRI) is a versatile tool which can measure spatial structure, diffusion, and flow velocities in three dimensions and in situ. It is well-suited to characterize biofilms under natural conditions and at different length scales. MRI contrast is dictated by <em>T</em>_<em>1</em> and <em>T</em>_<em>2</em> relaxation times which vary spatially depending on the local chemical and physical environment of the sample. Previous studies have demonstrated that MRI can provide important insights into the internal structure of biofilms, but the contribution of major biofilm components—such as proteins, polysaccharides, and cells—to MRI contrast is not fully understood. This study explores how these components affect contrast in <em>T</em>_<em>1</em><em>-</em>and <em>T</em>_<em>2</em>-weighted MRI by analyzing artificial biofilms with well-defined properties modeled after aerobic granular sludge (AGS), compact spherical biofilm aggregates used in wastewater treatment. MRI of these biofilm models showed that certain gel-forming polysaccharides are a major source of <em>T</em>_<em>2</em> contrast, while other polysaccharides show minimal contrast. Proteins were found to reduce <em>T</em>_<em>2</em> contrast slightly when combined with polysaccharides, while cells had a negligible impact on <em>T</em>_<em>2</em> but showed <em>T</em>_<em>1</em> contrast. Patterns observed in the model biofilms served as a reference for examining <em>T</em>_<em>2</em> and <em>T</em>_<em>1</em>-weighted contrast in the void spaces of two distinct AGS granules, allowing for a qualitative evaluation of the EPS components which may be present. Further insights provided by MRI may help improve understanding of the biofilm matrix and guide how to better manage biofilms in wastewater, clinical, and industrial settings.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100235"},"PeriodicalIF":5.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and comparison of protein composition of biofilms in response to EGCG from Enterococcus faecalis and Staphylococcus lugdunensis, which showed opposite patterns in biofilm-forming abilities","authors":"Jung-Ah Cho ,&nbsp;Sangsoo Jeon ,&nbsp;Youngmin Kwon ,&nbsp;Yoo Jin Roh ,&nbsp;Sukjin Shin ,&nbsp;Chang-Hun Lee ,&nbsp;Sung Jae Kim","doi":"10.1016/j.bioflm.2024.100232","DOIUrl":"10.1016/j.bioflm.2024.100232","url":null,"abstract":"<div><div>Bacterial biofilm is resistant to conventional antibiotic treatments, leading to complications associated with many infection-related human diseases. Epigallocatechin Gallate (EGCG), a phenolic catechin enriched in green tea, is recognized for its anti-bacterial and anti-biofilm activities. In this study, we examined the protein components of the biofilms formed in the absence or presence of EGCG using <em>Enterococcus faecalis</em> and <em>Staphylococcus lugdunensis,</em> which had shown opposing patterns in biofilm formation. A clustering heatmap revealed that the two microorganisms expressed the different protein sets in response to EGCG. Proteins that were noticeably upregulated included those associated with stress responsiveness and gluconeogenesis in <em>E. faecalis</em>, and gene modification in <em>S. lugdunensis</em>. Conversely, downregulated proteins were related to tRNA-modifying enzyme activity in <em>E. faecalis</em>, and anabolic metabolism in <em>S. lugdunensis</em>. Among the proteins identified only in EGCG-responsive biofilms, enzymes involved in de novo purine biosynthesis were enriched in <em>E. faecalis</em>, while proteins likely to cause DNA instability and pathogenicity changes were abundantly present in <em>S. lugdunensis</em>. The classification based on gene ontology (GO) terms by microorganism exhibited that metabolic process or catabolic activity was at the top rank in <em>E. faecalis</em> with more than 33 proteins, and in <em>S. lugdunensis</em>, localization or transport was highly ranked with 4 proteins. These results support the hypothesis that EGCG might cause different cellular programs in each microorganism. Finally, comparison of the proteomes between two groups that form biofilms to similar extents discovered that 2 proteins were commonly found in the weak biofilm-forming groups (<em>E. faecalis</em> and EGCG-responding <em>S. lugudunensis</em>), whereas 9 proteins were common among the strong biofilm-forming groups (<em>S. lugdunensis</em> and EGCG-responding <em>E. faecalis</em>). It was suggested that these proteins could serve as potential indicators to detect the presence and predict the extent of biofilm formation by multiple microorganisms. Taken all together, proteomics data and analyses performed in this study provided useful and new information on the proteins embedded in the biofilms formed at the specific conditions, which can aid in diagnosis and the development of tailored treatment strategies.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100232"},"PeriodicalIF":5.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cooperation between coagulase and von willebrand factor binding protein in Staphylococcus aureus fibrin pseudocapsule formation","authors":"Dominique C.S. Evans ,&nbsp;Amanda B. Khamas ,&nbsp;Alex Payne-Dwyer ,&nbsp;Adam J.M. Wollman ,&nbsp;Kristian S. Rasmussen ,&nbsp;Janne K. Klitgaard ,&nbsp;Birgitte Kallipolitis ,&nbsp;Mark C. Leake ,&nbsp;Rikke L. Meyer","doi":"10.1016/j.bioflm.2024.100233","DOIUrl":"10.1016/j.bioflm.2024.100233","url":null,"abstract":"<div><div>The major human pathogen <em>Staphylococcus aureus</em> forms biofilms comprising of a fibrin network that increases attachment to surfaces and shields bacteria from the immune system. It secretes two coagulases, Coagulase (Coa) and von Willebrand factor binding protein (vWbp), which hijack the host coagulation cascade and trigger the formation of this fibrin clot. However, it is unclear how Coa and vWbp contribute differently to the localisation and dynamics of clot assembly in growing biofilms.</div><div>Here, we address this question using high-precision time-resolved confocal microscopy of fluorescent fibrin to establish the spatiotemporal dynamics of fibrin clot formation in functional biofilms. We also use fluorescent fusion proteins to visualise the locations of Coa and vWbp in biofilms using both confocal laser scanning and high resolution highly inclined and laminated optical sheet microscopy. We visualise and quantify the spatiotemporal dynamics of fibrin production during initiation of biofilms in plasma amended with fluorescently labelled fibrinogen.</div><div>We find that human serum stimulates coagulase production, and that Coa and vWbp loosely associate to the bacterial cell surface. Coa localises to cell surfaces to produce a surface-attached fibrin pseudocapsule but can diffuse from cells to produce matrix-associated fibrin. vWbp produces matrix-associated fibrin in the absence of Coa, and furthermore accelerates pseudocapsule production when Coa is present. Finally, we observe that fibrin production varies across the biofilm. A sub-population of non-dividing cells does not produce any pseudocapsule but remains within the protective extended fibrin network, which could be important for the persistence of <em>S. aureus</em> biofilm infections as antibiotics are more effective against actively growing cells.</div><div>Our findings indicate a more cooperative role between Coa and vWbp in building fibrin networks than previously thought, and a bet-hedging cell strategy where some cells produce biofilm matrix while others do not, but instead assume a dormant phenotype that could be associated with antibiotic tolerance.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100233"},"PeriodicalIF":5.9,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collateral susceptibility-guided alternation of ceftolozane/tazobactam with imipenem prevents resistance development in XDR Pseudomonas aeruginosa biofilms","authors":"María Fernández-Billón ,&nbsp;Elena Jordana-Lluch ,&nbsp;Aina E. Llambías-Cabot ,&nbsp;María A. Gomis-Font ,&nbsp;Pablo Fraile-Ribot ,&nbsp;Rosa I. Torrandell ,&nbsp;Pamela J. Colman-Vega ,&nbsp;Óscar Murillo ,&nbsp;María D. Macià ,&nbsp;Antonio Oliver","doi":"10.1016/j.bioflm.2024.100231","DOIUrl":"10.1016/j.bioflm.2024.100231","url":null,"abstract":"<div><h3>Objectives</h3><div>New combinations of β-lactams and β-lactamase inhibitors, such as ceftolozane/tazobactam could be useful to combat biofilm-driven chronic infections by extensively resistant (XDR) <em>Pseudomonas aeruginosa</em> but resistance development by mutations in the Ω-loop of AmpC has been described. However, these mutations confer collateral susceptibility to carbapenems. Thus we aimed to evaluate the therapeutic efficacy and the prevention of resistance development of regimen alternating ceftolozane/tazobactam and imipenem.</div></div><div><h3>Methods</h3><div>A carbapenem-resistant XDR <em>P. aeruginosa</em> clinical strain (ST175, 104-B7) and its isogenic imipenem-susceptible ceftolozane/tazobactam-resistant mutant derivative (AmpC T96I, 104-I9) were used. Experiments of single strains and mixed (104-B7 and 104-I9, 1:0.01 ratio) biofilms were performed. 48h biofilms (flow cell system) were treated for 6 days with either ceftolozane/tazobactam, 4/4 mg/L or the alternation of ceftolozane/tazobactam (2 days)-imipenem 4 mg/L (2 days) - ceftolozane/tazobactam (2 days). After treatment, biofilms were collected and plated on Mueller-Hinton agar± ceftolozane/tazobactam 4/4 mg/L. Structural dynamics were monitored using confocal laser scanning microscopy and images were processed with IMARIS software. At least, three independent triplicate experiments per condition were performed. Emerging resistant mutants were characterized through whole genome sequencing (Illumina).</div></div><div><h3>Results</h3><div>Ceftolozane/tazobactam monotherapy failed to reduce the biofilms of the 104-B7 XDR strain and led to the selection of resistant mutants that showed AmpC Ω-loop mutations (T96I, L244R or aa236Δ7). On the contrary, alternation with imipenem enhanced activity (3 Logs reduction at day 6) and prevented the emergence of ceftolozane/tazobactam-resistant mutants. Likewise, treatment with ceftolozane/tazobactam dramatically amplified the resistant strain 104-I9 in mixed biofilms (&gt;90 % of the population), while the alternation regimen counterselected it.</div></div><div><h3>Conclusions</h3><div>Collateral susceptibility-guided alternation of ceftolozane/tazobactam with imipenem effectively prevented the selection of resistant mutants and thus could be a potential therapeutic strategy for the treatment of <em>P. aeruginosa</em> XDR chronic infections.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100231"},"PeriodicalIF":5.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma activated water pre-treatment substantially enhances phage activity against Proteus mirabilis biofilms","authors":"Akash Shambharkar ,&nbsp;Thomas P. Thompson ,&nbsp;Laura A. McClenaghan ,&nbsp;Paula Bourke ,&nbsp;Brendan F. Gilmore ,&nbsp;Timofey Skvortsov","doi":"10.1016/j.bioflm.2024.100230","DOIUrl":"10.1016/j.bioflm.2024.100230","url":null,"abstract":"<div><div>The ongoing antimicrobial resistance crisis has incentivised research into alternative antibacterial and antibiofilm agents. One of them is plasma-activated water (PAW), which is produced by exposing water to a cold plasma discharge. This process generates a diverse array of reactive oxygen and nitrogen species (ROS/RNS) with antimicrobial properties. Another intensively studied class of alternative antimicrobials are bacteriophages, attracting attention due to their specificity and strong antibacterial activity. As combinations of different types of antimicrobials are known to often exhibit synergistic interactions, in this study we investigated the combined use of cold atmospheric-pressure plasma-activated water and the bacteriophage vB_PmiS_PM-CJR against <em>Proteus mirabilis</em> biofilms as a potential option for treatment of catheter-associated urinary tract infections (CAUTIs).</div><div>We compared the effect of two cold plasma discharge setups for PAW production on its antimicrobial efficacy against <em>P. mirabilis</em> planktonic and biofilm cultures. Next, we assessed the stability of the phage vB_PmiS_PM-CJR in PAW. Finally, we tested the antimicrobial activity of the phages and PAW against biofilms, both individually and in combinations.</div><div>Our findings demonstrate that the combination of PAW with phage is more effective against biofilms compared to individual treatments, being able to reduce the number of biofilm-embedded cells by approximately 4 log. We were also able to show that the order of treatment plays an important role in the anti-biofilm activity of the phage-PAW combination, as the exposure of the biofilm to PAW prior to phage administration results in a stronger effect than the reverse order.</div><div>This research underlines PAW's ability to potentiate phage activity, showcasing a considerable reduction in biofilm viability and biomass. Additionally, it contributes to the growing body of evidence supporting the use of phage-based combinatorial treatments. Overall, this sequential treatment strategy demonstrates the potential of leveraging multiple approaches to address the mounting challenge of antibiotic resistance and offers a promising avenue for enhancing the efficacy of CAUTI management.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100230"},"PeriodicalIF":5.9,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear viscoelasticity of filamentous fungal biofilms of Neurospora discreta","authors":"N.M. Aiswarya ,&nbsp;Shamas Tabraiz ,&nbsp;Himani Taneja ,&nbsp;Asma Ahmed ,&nbsp;R. Aravinda Narayanan","doi":"10.1016/j.bioflm.2024.100227","DOIUrl":"10.1016/j.bioflm.2024.100227","url":null,"abstract":"<div><div>The picture of bacterial biofilms as a colloidal gel composed of rigid bacterial cells protected by extracellular crosslinked polymer matrix has been pivotal in understanding their ability to adapt their microstructure and viscoelasticity to environmental assaults. This work explores if an analogous perspective exists in fungal biofilms with long filamentous cells. To this end, we consider biofilms of the fungus <em>Neurospora discreta</em> formed on the air-liquid interface, which has shown an ability to remove excess nitrogen and phosphorous from wastewater effectively. We investigated the changes to the viscoelasticity and the microstructure of these biofilms when the biofilms uptake varying concentrations of nitrogen and phosphorous, using large amplitude oscillatory shear flow rheology (LAOS) and field-emission scanning electron microscopy (FESEM), respectively. A distinctive peak in the loss modulus (G″) at 30–50 % shear strain is observed, indicating the transition from an elastic to plastic deformation state. Though a peak in G″ has been observed in several soft materials, including bacterial biofilms, it has eluded interpretation in terms of quantifiable microstructural features. The central finding of this work is that the intensity of the G″ peak, signifying resistance to large deformations, correlates directly with the protein and polysaccharide concentrations per unit biomass in the extracellular matrix and inversely with the shear-induced changes in filament orientation in the hyphal network. These correlations have implications for the rational design of fungal biofilms with tuneable mechanical properties.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100227"},"PeriodicalIF":5.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}