Biofilm最新文献

{"title":"Combination of phages and antibiotics with enhanced killing efficacy against dual-species bacterial communities in a three-dimensional lung epithelial model","authors":"Ergun Akturk ,&nbsp;Graça Pinto ,&nbsp;Lisa Ostyn ,&nbsp;Aurélie Crabbé ,&nbsp;Luís D.R. Melo ,&nbsp;Joana Azeredo ,&nbsp;Tom Coenye","doi":"10.1016/j.bioflm.2024.100245","DOIUrl":"10.1016/j.bioflm.2024.100245","url":null,"abstract":"<div><div><em>Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus</em> are opportunistic pathogens commonly found in biofilm-associated polymicrobial respiratory infections that are challenging to control. Studies performed in laboratory standard conditions suggest that bacterio(phages) and antibiotic combinations are more active against bacterial communities and biofilms than each agent alone. The purpose of this work was to study the antibacterial efficacy of phage-antibiotic combinations using an <em>in vivo</em>-like three-dimensional lung epithelial model that mimics aspects of the parental tissue, colonized by a mixed bacterial community of <em>P. aeruginosa</em> and <em>S. aureus</em>. The bacterial population was targeted by phages specific to <em>P. aeruginosa</em> and/or gentamicin and ciprofloxacin. The results showed that <em>P. aeruginosa</em> was eradicated from the dual-species community when phage treatment was followed by gentamicin and was significantly reduced when followed by ciprofloxacin. Moreover, applying phages first followed by antibiotics demonstrated superior antibacterial activity compared to simultaneous treatment or treatments with the reverse order of application. This approach also reduced the <em>S. aureus</em> population but not as significant as the <em>P. aeruginosa</em> population. Using an <em>in vivo</em>-like model we demonstrated that phages and antibiotics are effective against dual-species bacterial communities, particularly targeting the <em>P. aeruginosa</em> population. However, but the sequence in which these antimicrobials are applied significantly in fluences the effectiveness of bacterial killing.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"9 ","pages":"Article 100245"},"PeriodicalIF":5.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101632","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":"RpoN mediates biofilm formation by directly controlling vps gene cluster and c-di-GMP synthetic metabolism in V. alginolyticus","authors":"Na Zhang ,&nbsp;Yanhua Zeng ,&nbsp;Jiachengzi Ye ,&nbsp;Chuancao Lin ,&nbsp;Xiaoxiao Gong ,&nbsp;Hao Long ,&nbsp;Haimin Chen ,&nbsp;Zhenyu Xie","doi":"10.1016/j.bioflm.2024.100242","DOIUrl":"10.1016/j.bioflm.2024.100242","url":null,"abstract":"<div><div><em>Vibrio alginolyticus</em> is a prevalent pathogen in both humans and marine species, exhibiting high adaptability to various adverse environmental conditions. Our previous studies have shown that Δ<em>rpoN</em> formed three enhanced biofilm types, including spectacular surface-attached biofilm (SB), scattered pellicle biofilm (PB), and colony rugosity. However, the precise mechanism through which <em>rpoN</em> regulates biofilm formation has remained unclear. Based on the critical role of Vibrio exopolysaccharide (VPS) in biofilm formation, several genes related to the production and regulation of VPS were characterized in <em>V. alginolyticus</em>. Our findings from mutant strains indicated that VPS has complete control over the formation of rugose colony morphology and PB, while it only partially contributes to SB formation. Among the four transcriptional regulators of the <em>vps</em> gene cluster, <em>vpsR</em> and VA3545 act as promoters, whereas VA3546 and VA2703 function as repressors. Through transcriptome analysis and c-di-GMP concentration determination, VA0356 and VA3580 which encoded diguanylate cyclase were found to mediate the Δ<em>rpoN</em> biofilm formation. As a central regulator, <em>rpoN</em> governed biofilm formation through two regulatory pathways. Firstly, it directly bound to the upstream region of VA4206 to regulate the expression of the <em>vps</em> gene cluster (VA4206-VA4196). Secondly, it directly and indirectly modulated c-di-GMP synthesis gene VA3580 and VA0356, respectively, thereby affecting c-di-GMP concentration and subsequently influencing the expression of <em>vps</em> transcription activators <em>vpsR</em> and VA3545. Under conditions promoting SB formation, Δ<em>rpoN</em> was unable to thrive below the liquid level due to significantly reduced activities of three catalytic enzymes (ACK, ADH, and ALDH) involved in pyruvate metabolism, but tended to reproduce in air-liquid interface, a high oxygen niche compared to the liquid phase. In conclusion, both exopolysaccharide synthesis and oxygen-related metabolism contributed to Δ<em>rpoN</em> biofilm formation. The role of RpoN-mediated hypoxic metabolism and biofilm formation were crucial for comprehending the colonization and pathogenicity of <em>V. alginolyticus</em> in hosts, providing a novel target for treating <em>V. alginolyticus</em> in aquatic environments and hosts.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"9 ","pages":"Article 100242"},"PeriodicalIF":5.9,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11722192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142973488","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":"Investigations into the growth and formation of biofilm by Leptospira biflexa at temperatures encountered during infection","authors":"Priscyla dos Santos Ribeiro ,&nbsp;Judith Stasko ,&nbsp;Adrienne Shircliff ,&nbsp;Luis Guilherme Fernandes ,&nbsp;Ellie J. Putz ,&nbsp;Claire Andreasen ,&nbsp;Vasco Azevedo ,&nbsp;Paula Ristow ,&nbsp;Jarlath E. Nally","doi":"10.1016/j.bioflm.2024.100243","DOIUrl":"10.1016/j.bioflm.2024.100243","url":null,"abstract":"<div><div>The genus <em>Leptospira</em> comprises unique atypical spirochete bacteria that includes the etiological agent of leptospirosis, a globally important zoonosis. Biofilms are microecosystems composed of microorganisms embedded in a self-produced matrix that offers protection against hostile factors. Leptospires form biofilms <em>in vitro, in situ</em> in rice fields and unsanitary urban areas, and <em>in vivo</em> while colonizing rodent kidneys. The complex three-dimensional biofilm matrix includes secreted polymeric substances such as proteins, extracellular DNA (eDNA), and saccharides. The genus <em>Leptospira</em> comprises pathogenic and saprophytic species with the saprophytic <em>L. biflexa</em> being commonly used as a model organism for the genus. In this study, the growth and formation of biofilms by <em>L. biflexa</em> was investigated not just at 29 °C, but at 37 °C/5 % CO₂, a temperature similar to that encountered during host infection. Planktonic free-living <em>L. biflexa</em> grow in HAN media at both 29 °C and 37 °C/5 % CO_2, but cells grown at 37 °C/5 % CO₂ are longer (18.52 μm ± 3.39) compared to those at 29 °C (13.93 μm ± 2.84). Biofilms formed at 37 °C/5 % CO₂ had more biomass compared to 29 °C, as determined by crystal violet staining. Confocal microscopy determined that the protein content within the biofilm matrix was more prominent than double-stranded DNA, and featured a distinct layer attached to the solid substrate. Additionally, the model enabled effective protein extraction for proteomic comparison across different biofilm phenotypes. Results highlight an important role for proteins in biofilm matrix structure by leptospires and the identification of their specific protein components holds promise for strategies to mitigate biofilm formation.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"9 ","pages":"Article 100243"},"PeriodicalIF":5.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11697785/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142933665","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":"Usnic acid brief exposure suppresses cariogenic properties and complexity of Streptococcus mutans biofilms","authors":"Santosh Pandit ,&nbsp;Mi-A Kim ,&nbsp;Ji-Eun Jung ,&nbsp;Hyeon-Mi Choi ,&nbsp;Jae-Gyu Jeon","doi":"10.1016/j.bioflm.2024.100241","DOIUrl":"10.1016/j.bioflm.2024.100241","url":null,"abstract":"<div><div>Bacterial biofilms are highly structured surface associated architecture of micro-colonies, which are strongly bonded with the exopolymeric matrix of their own synthesis. These exopolymeric substances, mainly exopolysaccharides (EPS) initially assist the bacterial adhesion and finally form a bridge over the microcolonies to protect them from environmental assaults and antimicrobial exposure. Bacterial cells in dental biofilm metabolize dietary carbohydrates and produce organic acids. The blanket of exopolysaccharides over the bacterial communities hinders the buffering by saliva, contributing to the initiation of tooth decay followed by the progression of dental caries. Considering the current interest towards the use of natural antimicrobial agents to disarm the cariogenic properties of dental biofilm, this study evaluated the antimicrobial activity and the effect of twice daily brief exposure (1 min) of usnic acid on acid production, acid tolerance and development of 3-dimensional architecture of <em>Streptococcus mutans</em> biofilm. Herein, biofilms were briefly treated twice daily during biofilm development and biofilms were analyzed by using biochemical, microbiological and microscopic examination. Results obtained in this study showed a significant reduction in virulence properties of biofilm cells treated with usnic acid in compared to non-treated biofilms. Furthermore, twice daily brief exposure of usnic acid significantly disrupted the acid production and reduced the complexity of <em>Streptococcus mutans</em> biofilm by disrupting the EPS production. Brief exposure of usnic acid inhibited the production of glucosyltransferase (GTF) enzymes and their enzymatic activity leading to inhibition in production of EPS on the biofilm matrix. In conclusion, usnic acid treatment reduced the cariogenic properties and complexity of <em>S. mutans</em> biofilm by inhibiting acid production, acid tolerance and disrupting extracellular polysaccharide (EPS) formation, indicating its potential for preventing dental caries.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100241"},"PeriodicalIF":5.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11652789/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142856915","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":"Bridging the Gap: Biofilm-mediated establishment of Bacillus velezensis on Trichoderma guizhouense mycelia","authors":"Jiyu Xie ,&nbsp;Xinli Sun ,&nbsp;Yanwei Xia ,&nbsp;Lili Tao ,&nbsp;Taimeng Tan ,&nbsp;Nan Zhang ,&nbsp;Weibing Xun ,&nbsp;Ruifu Zhang ,&nbsp;Ákos T. Kovács ,&nbsp;Zhihui Xu ,&nbsp;Qirong Shen","doi":"10.1016/j.bioflm.2024.100239","DOIUrl":"10.1016/j.bioflm.2024.100239","url":null,"abstract":"<div><div>Bacterial-fungal interactions (BFIs) are important in ecosystem dynamics, especially within the soil rhizosphere. The bacterium <em>Bacillus velezensis</em> SQR9 and the fungus <em>Trichoderma guizhouense</em> NJAU 4742 have gathered considerable attention due to their roles in promoting plant growth and protecting their host against pathogens. In this study, we utilized these two model microorganisms to investigate BFIs. We firstly demonstrate that while co-inoculation of <em>B. velezensis</em> and <em>T. guizhouense</em> could promote tomato growth, these two microorganisms display mutual antagonism on agar solidified medium. To resolve this contradiction, we developed an inoculation method, that allows <em>B. velezensis</em> colonization of <em>T</em>. <em>guizhouense</em> hyphae and performed a transcriptome analysis. During colonization of the fungal hyphae, <em>B. velezensis</em> SQR9 upregulates expression of biofilm related genes (e.g. <em>eps, tasA</em>, and <em>bslA)</em> that is distinct from free-living cells. This result suggested an intricate association between extracellular matrix expression and hyphae colonization. In accordance, deletion <em>epsD</em>, <em>tasA, or</em> both <em>epsD</em> and <em>tasA</em> genes of <em>B. velezensis</em> diminished colonization of the <em>T</em>. <em>guizhouense</em> hyphae. The insights from our study demonstrate that soil BFIs are more complex than we understood, potentially involving both competition and cooperation. These intricate biofilm-mediated BFI dynamics might contribute to the remarkable diversity observed within soil microbiota, providing a fresh perspective for further exploration of BFIs in the plant rhizosphere.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100239"},"PeriodicalIF":5.9,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706666","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":"Effect of shear rate on early Shewanella oneidensis adhesion dynamics monitored by deep learning","authors":"Lucie Klopffer ,&nbsp;Nicolas Louvet ,&nbsp;Simon Becker ,&nbsp;Jérémy Fix ,&nbsp;Cédric Pradalier ,&nbsp;Laurence Mathieu","doi":"10.1016/j.bioflm.2024.100240","DOIUrl":"10.1016/j.bioflm.2024.100240","url":null,"abstract":"<div><div>Understanding pioneer bacterial adhesion is essential to appreciate bacterial colonization and consider appropriate control strategies. This bacterial entrapment at the wall is known to be controlled by many physical, chemical or biological factors, including hydrodynamic conditions. However, due to the nature of early bacterial adhesion, i.e. a short and dynamic process with low biomass involved, such investigations are challenging. In this context, our study aimed to evaluate the effect of wall shear rate on the early bacterial adhesion dynamics. Firstly, at the population scale by assessing bacterial colonization kinetics and the mechanisms responsible for wall transfer under shear rates using a time-lapse approach. Secondly, at the individual scale, by implementing an automated image processing method based on deep learning to track each individual pioneer bacterium on the wall. Bacterial adhesion experiments are performed on a model bacterium (<em>Shewanella oneidensis</em> MR-1) at different shear rates (0 to1250 s⁻¹) in a microfluidic system mounted under a microscope equipped with a CCD camera. Image processing was performed using a trained neural network (YOLOv8), which allowed information extraction, i.e. bacterial wall residence time and orientation for each adhered bacterium during pioneer colonization (14 min). Collected from over 20,000 bacteria, our results showed that adhered bacteria had a very short residence time at the wall, with over 70 % remaining less than 1 min. Shear rates had a non-proportional effect on pioneer colonization with a bell-shape profile suggesting that intermediate shear rates improved both bacterial wall residence time as well as colonization rate and level. This lack of proportionality highlights the dual effect of wall shear rate on early bacterial colonization; initially increasing it improves bacterial colonization up to a threshold, beyond which it leads to higher bacterial wall detachment. The present study provides quantitative data on the individual dynamics of just adhered bacteria within a population when exposed to different rates of wall shear.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100240"},"PeriodicalIF":5.9,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706667","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":"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}