Biofilm最新文献

{"title":"A normalized parameter for comparison of biofilm dispersants in vitro","authors":"Shuang Tian ,&nbsp;Linqi Shi ,&nbsp;Yijin Ren ,&nbsp;Henny C. van der Mei ,&nbsp;Henk J. Busscher","doi":"10.1016/j.bioflm.2024.100188","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100188","url":null,"abstract":"<div><p>Dispersal of infectious biofilms increases bacterial concentrations in blood. To prevent sepsis, the strength of a dispersant should be limited to allow the immune system to remove dispersed bacteria from blood, preferably without antibiotic administration. Biofilm bacteria are held together by extracellular polymeric substances that can be degraded by dispersants. Currently, comparison of the strength of dispersants is not possible by lack of a suitable comparison parameter. Here, a biofilm dispersal parameter is proposed that accounts for differences in initial biofilm properties, dispersant concentration and exposure time by using PBS as a control and normalizing outcomes with respect to concentration and time. The parameter yielded near-identical values based on dispersant-induced reductions in biomass or biofilm colony-forming-units and appeared strain-dependent across pathogens. The parameter as proposed is largely independent of experimental methods and conditions and suitable for comparing different dispersants with respect to different causative strains in particular types of infection.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100188"},"PeriodicalIF":6.8,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000133/pdfft?md5=c72c8fc107d3d2c9b9ce5030de4009a2&pid=1-s2.0-S2590207524000133-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140063130","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":"Efficacy of rifampicin combination therapy against MRSA prosthetic vascular graft infections in a rat model","authors":"Mikkel Illemann Johansen ,&nbsp;Maiken Engelbrecht Petersen ,&nbsp;Emma Faddy ,&nbsp;Anders Marthinsen Seefeldt ,&nbsp;Alexander Alexandrovich Mitkin ,&nbsp;Lars Østergaard ,&nbsp;Rikke Louise Meyer ,&nbsp;Nis Pedersen Jørgensen","doi":"10.1016/j.bioflm.2024.100189","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100189","url":null,"abstract":"<div><p><em>Staphylococcus aureus</em> is a major cause of prosthetic vascular graft or endograft infections (VGEIs) and the optimal choice of antibiotics is unclear. We investigated various antibiotic choices as either monotherapy or combination therapy with rifampicin against MRSA <em>in vitro</em> and <em>in vivo</em>.</p><p>Fosfomycin, daptomycin and vancomycin alone or in combination with rifampicin was used against MRSA USA300 FPR3757. Each antibiotic was tested for synergism or antagonism with rifampicin <em>in vitro,</em> and all antibiotic regimens were tested against actively growing bacteria in media and non-growing bacteria in buffer, both as planktonic cells and in biofilms. A rat model of VGEI was used to quantify the therapeutic efficacy of antibiotics <em>in vivo</em> by measuring bacterial load on grafts and in spleen, liver and kidneys.</p><p><em>In vitro,</em> rifampicin combinations did not reveal any synergism or antagonism in relation to growth inhibition. However, quantification of bactericidal activity revealed a strong antagonistic effect, both on biofilms and planktonic cells. This effect was only observed when treating active bacteria, as all antibiotics had little or no effect on inactive cells. Only daptomycin showed some biocidal activity against inactive cells. <em>In vivo</em> evaluation of therapy against VGEI contrasted the <em>in vitro</em> results<em>.</em> Rifampicin significantly increased the efficacy of both daptomycin and vancomycin. The combination of daptomycin and rifampicin was by far the most effective, curing 8 of 13 infected animals.</p><p>Our study demonstrates that daptomycin in combination with rifampicin shows promising potential against VGEI caused by MRSA. Furthermore, we show how <em>in vitro</em> evaluation of antibiotic combinations in laboratory media does not predict their therapeutic effect against VGEI <em>in vivo</em>, presumably due to a difference in the metabolic state of the bacteria.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100189"},"PeriodicalIF":6.8,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000145/pdfft?md5=e95db5a749838693e3087c7d7413e390&pid=1-s2.0-S2590207524000145-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140041562","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":"UV emitting glass: A promising strategy for biofilm inhibition on transparent surfaces","authors":"Leila Alidokht ,&nbsp;Katrina Fitzpatrick ,&nbsp;Caitlyn Butler ,&nbsp;Kelli Z. Hunsucker ,&nbsp;Cierra Braga ,&nbsp;William A. Maza ,&nbsp;Kenan P. Fears ,&nbsp;Marieh Arekhi ,&nbsp;Mariana Lanzarini-Lopes","doi":"10.1016/j.bioflm.2024.100186","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100186","url":null,"abstract":"<div><p>Marine biofouling causes serious environmental problems and has adverse impacts on the maritime industry. Biofouling on windows and optical equipment reduces surface transparency, limiting their application for on-site monitoring or continuous measurement. This work illustrates that UV emitting glasses (UEGs) can prevent the establishment and growth of biofilm on the illuminated surfaces. Specifically, this paper describes how UEGs are enabled by innovatively modifying the surfaces of the glass with light scattering particles. Modification of glass surface with silica nanoparticles at a concentration 26.5 μg/cm² resulted in over ten-fold increase in UV irradiance, while maintaining satisfactory visible and IR transparency metrics of over 99 %. The UEG reduced visible biological growth by 98 % and resulted in a decrease of 1.79 log in detected colony forming units when compared to the control during a 20 day submersion at Port Canaveral, Florida, United States. These findings serve as strong evidence that UV emitting glass should be explored as a promising approach for biofilm inhibition on transparent surfaces.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100186"},"PeriodicalIF":6.8,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259020752400011X/pdfft?md5=e4deb4ca639f1e52c5c299dc254470d1&pid=1-s2.0-S259020752400011X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140069468","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":"Critical analysis of methods to determine growth, control and analysis of biofilms for potential non-submerged antibiofilm surfaces and coatings","authors":"J. Redfern ,&nbsp;A.J. Cunliffe ,&nbsp;D.M. Goeres ,&nbsp;N.F. Azevedo ,&nbsp;J. Verran","doi":"10.1016/j.bioflm.2024.100187","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100187","url":null,"abstract":"<div><p>The potential uses for antibiofilm surfaces reach across different sectors with significant resultant economic, societal and health impact. For those interested in using antibiofilm surfaces in the built environment, it is important that efficacy testing methods are relevant, reproducible and standardised where possible, to ensure data outputs are applicable to end-use, and comparable across the literature. Using pre-defined keywords, a review of literature reporting on antimicrobial surfaces (78 articles), within which a potential application was described as non-submerged/non-medical surface or coating with antibiofilm action, was undertaken. The most used methods utilized the growth of biofilm in submerged and static systems. Quantification varied (from most to least commonly used) across colony forming unit counts, non-microscopy fluorescence or spectroscopy, microscopy analysis, direct agar-contact, sequencing, and ELISA. Selection of growth media, microbial species, and incubation temperature also varied. In many cases, definitions of biofilm and attempts to quantify antibiofilm activity were absent or vague. Assessing a surface after biofilm recovery or assessing potential regrowth of a biofilm after initial analysis was almost entirely absent. It is clear the field would benefit from widely agreed and adopted approaches or guidance on how to select and incorporate end-use specific conditions, alongside minimum reporting guidelines may benefit the literature.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100187"},"PeriodicalIF":6.8,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000121/pdfft?md5=a01ed8c7a2d67bcedbaee54280da22ab&pid=1-s2.0-S2590207524000121-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140041545","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":"The use of biomimetic surfaces to reduce single- and dual-species biofilms of Escherichia coli and Pseudomonas putida","authors":"Rita Teixeira-Santos ,&nbsp;Ana Azevedo ,&nbsp;Maria J. Romeu ,&nbsp;Cristina I. Amador ,&nbsp;Luciana C. Gomes ,&nbsp;Kathryn A. Whitehead ,&nbsp;Jelmer Sjollema ,&nbsp;Mette Burmølle ,&nbsp;Filipe J. Mergulhão","doi":"10.1016/j.bioflm.2024.100185","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100185","url":null,"abstract":"<div><p>The ability of bacteria to adhere to and form biofilms on food contact surfaces poses serious challenges, as these may lead to the cross-contamination of food products. Biomimetic topographic surface modifications have been explored to enhance the antifouling performance of materials. In this study, the topography of two plant leaves, <em>Brassica oleracea</em> var. <em>botrytis</em> (cauliflower, CF) and <em>Brassica oleracea capitate</em> (white cabbage, WC), was replicated through wax moulding, and their antibiofilm potential was tested against single- and dual-species biofilms of <em>Escherichia coli</em> and <em>Pseudomonas putida</em>. Biomimetic surfaces exhibited higher roughness values (<em>S</em>_<em>a</em> _WC = 4.0 ± 1.0 μm and <em>S</em>_<em>a</em> _CF = 3.3 ± 1.0 μm) than the flat control (<em>S</em>_<em>a</em> _F = 0.6 ± 0.2 μm), whilst the CF surface demonstrated a lower interfacial free energy (<em>ΔG</em>_<em>iwi</em>) than the WC surface (−100.08 mJ m⁻² and −71.98 mJ m⁻², respectively). The CF and WC surfaces had similar antibiofilm effects against single-species biofilms, achieving cell reductions of approximately 50% and 60% for <em>E. coli</em> and <em>P. putida</em>, respectively, compared to the control. Additionally, the biomimetic surfaces led to reductions of up to 60% in biovolume, 45% in thickness, and 60% in the surface coverage of single-species biofilms. For dual-species biofilms, only the <em>E. coli</em> strain growing on the WC surface exhibited a significant decrease in the cell count. However, confocal microscopy analysis revealed a 60% reduction in the total biovolume and surface coverage of mixed biofilms developed on both biomimetic surfaces. Furthermore, dual-species biofilms were mainly composed of <em>P. putida</em>, which reduced <em>E. coli</em> growth. Altogether, these results demonstrate that the surface properties of CF and WC biomimetic surfaces have the potential for reducing biofilm formation.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100185"},"PeriodicalIF":6.8,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000108/pdfft?md5=23e4ee41bb43669ceb9cc195da841e72&pid=1-s2.0-S2590207524000108-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139992578","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":"SCCmec transformation requires living donor cells in mixed biofilms","authors":"Mais Maree ,&nbsp;Yuri Ushijima ,&nbsp;Pedro B. Fernandes ,&nbsp;Masato Higashide ,&nbsp;Kazuya Morikawa","doi":"10.1016/j.bioflm.2024.100184","DOIUrl":"10.1016/j.bioflm.2024.100184","url":null,"abstract":"<div><p>Methicillin-resistant <em>Staphylococcus aureus</em> (MRSA) is an important human pathogen that has emerged through the horizontal acquisition of the staphylococcal cassette chromosome <em>mec</em> (SCC<em>mec</em>). Previously, we showed that SCC<em>mec</em> from heat-killed donors can be transferred via natural transformation in biofilms at frequencies of 10⁻⁸-10⁻⁷. Here, we show an improved transformation assay of SCC<em>mec</em> with frequencies up to 10⁻² using co-cultured biofilms with living donor cells. The Ccr-<em>attB</em> system played an important role in SCC<em>mec</em> transfer, and the deletion of <em>ccrAB</em> recombinase genes reduced the frequency ∼30-fold. SCC<em>mec</em> could be transferred from either MRSA or methicillin-resistant coagulase-negative staphylococci to some methicillin-sensitive <em>S. aureus</em> recipients. In addition, the transformation of other plasmid or chromosomal genes is enhanced by using living donor cells. This study emphasizes the role of natural transformation as an evolutionary ability of <em>S. aureus</em> and in MRSA emergence.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100184"},"PeriodicalIF":6.8,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000091/pdfft?md5=6ab403cc3347bb7ec8e3d4d025fc14c6&pid=1-s2.0-S2590207524000091-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139966039","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":"Bioenergetics of simultaneous oxygen and nitrate respiration and nitric oxide production in a Pseudomonas aeruginosa agar colony biofilm","authors":"Paul Stoodley ,&nbsp;Nina Toelke ,&nbsp;Carsten Schwermer ,&nbsp;Dirk de Beer","doi":"10.1016/j.bioflm.2024.100181","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100181","url":null,"abstract":"<div><p><em>Pseudomonas aeruginosa</em> is a biofilm forming pathogen commonly associated with infection of the cystic fibrosis (CF) lung, chronic wounds and indwelling medical devices. <em>P. aeruginosa</em> is a facultative aerobe that can use nitrate (NO₃⁻) found in healthy and infected tissues and body fluids to generate energy through denitrification. Further, <em>P. aeruginosa</em> the expression of denitrification genes has been found in specimens from people with CF. The main aim of this study was to determine the relative energy contribution of oxygen (O₂) respiration and denitrification in single <em>Pseudomonas aeruginosa</em> PAO1 biofilm colonies under different O₂ concentrations to estimate the possible relative importance of these metabolic processes in the context of biofilm infections. We showed that the used strain PAO1 in biofilms denitrified with nitrous oxide (N₂O), and not nitrogen (N₂), as the end product in our incubations. From simultaneous O₂ and N₂O microprofiles measured with high spatial resolution by microsensors in agar colony biofilms under air, N₂ and pure O₂, the rates of aerobic respiration and denitrification were calculated and converted to ATP production rates. Denitrification occurred both in the oxic and anoxic zones, and became increasingly dominant with decreasing O₂ concentrations. At O₂ concentrations characteristic for tissues and wounds (20–60 μM), denitrification was responsible for 50% of the total energy conservation in the biofilm. In addition the formation of nitric oxide (NO), a precursor of N₂O and an important regulator of many cellular processes, was strongly influenced by the local O₂ concentrations. NO production was inhibited under pure O₂, present under anoxia (∼1 μM) and remarkably high (up to 6 μM) under intermediate O₂ levels, which can be found in infected tissues. Possible impacts of such NO levels on both the host and the biofilm bacteria are discussed.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100181"},"PeriodicalIF":6.8,"publicationDate":"2024-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000066/pdfft?md5=d0f7f9d538ef9328626d916b249a3bcf&pid=1-s2.0-S2590207524000066-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139936183","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":"Fluoropyrimidines affect de novo pyrimidine synthesis impairing biofilm formation in Escherichia coli","authors":"Srikanth Ravishankar ,&nbsp;Valerio Baldelli ,&nbsp;Carlo Angeletti ,&nbsp;Nadia Raffaelli ,&nbsp;Paolo Landini ,&nbsp;Elio Rossi","doi":"10.1016/j.bioflm.2024.100180","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100180","url":null,"abstract":"<div><p>Antivirulence agents are considered a promising strategy to treat bacterial infections. Fluoropyrimidines possess antivirulence and antibiofilm activity against Gram-negative bacteria; however, their mechanism of action is yet unknown. Consistent with their known antibiofilm activity, fluoropyrimidines, particularly 5-fluorocytosine (5-FC), impair curli-dependent surface adhesion by <em>Escherichia coli</em> MG1655 via downregulation of curli fimbriae gene transcription. Curli inhibition requires fluoropyrimidine conversion into fluoronucleotides and is not mediated by <em>c</em>-di-GMP or the <em>ymg-rcs</em> envelope stress response axis, previously suggested as the target of fluorouracil antibiofilm activity in <em>E. coli</em>. In contrast, 5-FC hampered the transcription of curli activators RpoS and stimulated the expression of Fis, a curli repressor affected by nucleotide availability. This last observation suggested a possible perturbation of the <em>de novo</em> pyrimidine biosynthesis by 5-FC: indeed, exposure to 5-FC resulted in a ca. 2-fold reduction of UMP intracellular levels while not affecting ATP. Consistently, expression of the <em>de novo</em> pyrimidine biosynthesis genes <em>carB</em> and <em>pyrB</em> was upregulated in the presence of 5-FC. Our results suggest that the antibiofilm activity of fluoropyrimidines is mediated, at least in part, by perturbation of the pyrimidine nucleotide pool. We screened a genome library in search of additional determinants able to counteract the effects of 5-FC. We found that a DNA fragment encoding the unknown protein D8B36_18,480 and the <em>N</em>-terminal domain of the penicillin-binding protein 1b (PBP1b), involved in peptidoglycan synthesis, could restore curli production in the presence of 5-FC. Deletion of the PBP1b-encoding gene <em>mrcB</em>, induced <em>csgBAC</em> transcription, while overexpression of the gene encoding the D8B36_18,480 protein obliterated its expression, possibly as part of a coordinated response in curli regulation with PBP1b. While the two proteins do not appear to be direct targets of 5-FC, their involvement in curli regulation suggests a connection between peptidoglycan biosynthesis and curli production, which might become even more relevant upon pyrimidine starvation and reduced availability of UDP-sugars needed in cell wall biosynthesis. Overall, our findings link the antibiofilm activity of fluoropyrimidines to the redirection of at least two global regulators (RpoS, Fis) by induction of pyrimidine starvation. This highlights the importance of the <em>de novo</em> pyrimidines biosynthesis pathway in controlling virulence mechanisms in different bacteria and makes the pathway a potential target for antivirulence strategies.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100180"},"PeriodicalIF":6.8,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000054/pdfft?md5=ee9bdd5d81f3bebbc6dd28d57a6ac40e&pid=1-s2.0-S2590207524000054-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139719658","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":"Dual roles of the conditional extracellular vesicles derived from Pseudomonas aeruginosa biofilms: Promoting and inhibiting bacterial biofilm growth","authors":"Marwa Gamal Saad,&nbsp;Haluk Beyenal,&nbsp;Wen-Ji Dong","doi":"10.1016/j.bioflm.2024.100183","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100183","url":null,"abstract":"<div><p>Antibiotic-resistant biofilm infections have emerged as public health concerns because of their enhanced tolerance to high-dose antibiotic treatments. The biofilm life cycle involves multiple developmental stages, which are tightly regulated by active cell-cell communication via specific extracellular signal messengers such as extracellular vesicles. This study was aimed at exploring the roles of extracellular vesicles secreted by <em>Pseudomonas aeruginosa</em> at different developmental stages in controlling biofilm growth. Our results show that extracellular vesicles secreted by <em>P. aeruginosa</em> biofilms during their exponential growth phase (G-EVs) enhance biofilm growth. In contrast, extracellular vesicles secreted by <em>P. aeruginosa</em> biofilms during their death/survival phase (D-EVs) can effectively inhibit/eliminate <em>P. aeruginosa</em> PAO1 biofilms up to 4.8-log₁₀ CFU/cm². The inhibition effectiveness of D-EVs against <em>P. aeruginosa</em> biofilms grown for 96 h improved further in the presence of 10–50 μM Fe³⁺ ions. Proteomic analysis suggests the inhibition involves an iron-dependent ferroptosis mechanism. This study is the first to report the functional role of bacterial extracellular vesicles in bacterial growth, which depends on the developmental stage of the parent bacteria. The finding of D-EV-activated ferroptosis-based bacterial death may have significant implications for preventing antibiotic resistance in biofilms.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100183"},"PeriodicalIF":6.8,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259020752400008X/pdfft?md5=159d0d8522a5a1c09e88ea8c53c7b493&pid=1-s2.0-S259020752400008X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139726151","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":"Space biofilms – An overview of the morphology of Pseudomonas aeruginosa biofilms grown on silicone and cellulose membranes on board the international space station","authors":"Pamela Flores ,&nbsp;Jiaqi Luo ,&nbsp;Daniel Wyn Mueller ,&nbsp;Frank Muecklich ,&nbsp;Luis Zea","doi":"10.1016/j.bioflm.2024.100182","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100182","url":null,"abstract":"<div><p>Microorganisms’ natural ability to live as organized multicellular communities – also known as biofilms – provides them with unique survival advantages. For instance, bacterial biofilms are protected against environmental stresses thanks to their extracellular matrix, which could contribute to persistent infections after treatment with antibiotics. Bacterial biofilms are also capable of strongly attaching to surfaces, where their metabolic by-products could lead to surface material degradation. Furthermore, microgravity can alter biofilm behavior in unexpected ways, making the presence of biofilms in space a risk for both astronauts and spaceflight hardware. Despite the efforts to eliminate microorganism contamination from spacecraft surfaces, it is impossible to prevent human-associated bacteria from eventually establishing biofilm surface colonization. Nevertheless, by understanding the changes that bacterial biofilms undergo in microgravity, it is possible to identify key differences and pathways that could be targeted to significantly reduce biofilm formation. The bacterial component of Space Biofilms project, performed on the International Space Station in early 2020, contributes to such understanding by characterizing the morphology and gene expression of bacterial biofilms formed in microgravity with respect to ground controls. <em>Pseudomonas aeruginosa</em> was used as model organism due to its relevance in biofilm studies and its ability to cause urinary tract infections as an opportunistic pathogen. Biofilm formation was characterized at one, two, and three days of incubation (37 °C) over six different materials. Materials reported in this manuscript include catheter grade silicone, selected due to its medical relevance in hospital acquired infections, catheter grade silicone with ultrashort pulsed direct laser interference patterning, included to test microtopographies as a potential biofilm control strategy, and cellulose membrane to replicate the column and canopy structure previously reported from a microgravity study. We here present an overview of the biofilm morphology, including 3D images of the biofilms to represent the distinctive morphology observed in each material tested, and some of the key differences in biofilm thickness, mass, and surface area coverage. We also present the impact of the surface microtopography in biofilm formation across materials, incubation time, and gravitational conditions.</p><p>The Space Biofilms project (bacterial side) is supported by the <span>National Aeronautics and Space Administration</span> under Grant No. 80NSSC17K0036 and 80NSSC21K1950.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100182"},"PeriodicalIF":6.8,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000078/pdfft?md5=c2d605d4c37c6e75fd4d5159a94909d9&pid=1-s2.0-S2590207524000078-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139719592","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}