Biofilm最新文献

{"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}

{"title":"Biofilm morphology and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) on poly-D,L-lactide-co-poly(ethylene glycol) (PDLLA-PEG) coated titanium","authors":"Adam Benedict Turner ,&nbsp;David Zermeño-Pérez ,&nbsp;Margaritha M. Mysior ,&nbsp;Paula Milena Giraldo-Osorno ,&nbsp;Begoña García ,&nbsp;Elizabeth O'Gorman ,&nbsp;Shafik Oubihi ,&nbsp;Jeremy C. Simpson ,&nbsp;Iñigo Lasa ,&nbsp;Tadhg Ó Cróinín ,&nbsp;Margarita Trobos","doi":"10.1016/j.bioflm.2024.100228","DOIUrl":"10.1016/j.bioflm.2024.100228","url":null,"abstract":"<div><div>Biodegradable polymeric coatings are being explored as a preventive strategy for orthopaedic device-related infection. In this study, titanium surfaces (Ti) were coated with poly-D,L-lactide (PDLLA, (P)), polyethylene-glycol poly-D,L-lactide <strong>(</strong>PEGylated-PDLLA, (PP20)), or multi-layered PEGylated-PDLLA (M), with or without 1 % silver sulfadiazine. The aim was to evaluate their cytocompatibility, resistance to <em>Staphylococcus aureus</em> biofilm formation, and their potential to enhance the susceptibility of any biofilm formed to antibiotics. Using automated high-content screening confocal microscopy, biofilm formation of a clinical methicillin-resistant <em>Staphylococcus aureus</em> (MRSA) isolate expressing GFP was quantified, along with isogenic mutants that were unable to form polysaccharidic or proteinaceous biofilm matrices. The results showed that PEGylated-PDLLA coatings exhibited significant antibiofilm properties, with M showing the highest effect. This inhibitory effect was stronger in <em>S. aureus</em> biofilms with a matrix composed of proteins compared to those with an exopolysaccharide (PIA) biofilm matrix. Our data suggest that the antibiofilm effect may have been due to (i) inhibition of the initial attachment through microbial surface components recognising adhesive matrix molecules (MSCRAMMs), since PEG reduces protein surface adsorption via surface hydration layer and steric repulsion; and (ii) mechanical disaggregation and dispersal of microcolonies due to the bioresorbable/degradable nature of the polymers, which undergo hydration and hydrolysis over time. The disruption of biofilm morphology by the PDLLA-PEG co-polymers increased <em>S. aureus</em> susceptibility to antibiotics like rifampicin and fusidic acid. Adding 1 % AgSD provided additional early bactericidal effects on both biofilm and planktonic <em>S. aureus</em>. Additionally, the coatings were cytocompatible with immune cells, indicating their potential to enhance bacterial clearance and reduce bacterial colonisation of titanium-based orthopaedic biomaterials.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100228"},"PeriodicalIF":5.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433643","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":"Large-scale screening identifies enzyme combinations that remove in situ grown oral biofilm","authors":"Signe Maria Nielsen ,&nbsp;Karina Kambourakis Johnsen ,&nbsp;Lea Benedicte Skov Hansen ,&nbsp;Pernille Dukanovic Rikvold ,&nbsp;Andreas Møllebjerg ,&nbsp;Lorena Gonzalez Palmén ,&nbsp;Thomas Durhuus ,&nbsp;Sebastian Schlafer ,&nbsp;Rikke Louise Meyer","doi":"10.1016/j.bioflm.2024.100229","DOIUrl":"10.1016/j.bioflm.2024.100229","url":null,"abstract":"<div><div>Bacteria in the oral cavity are responsible for the development of dental diseases such as caries and periodontitis, but it is becoming increasingly clear that the oral microbiome also benefits human health. Many oral care products on the market are antimicrobial, killing a large part of the oral microbiome but without removing the disease-causing biofilm. Instead, non-biocidal matrix-degrading enzymes may be used to selectively remove biofilm without harming the overall microbiome.</div><div>The challenge of using enzymes to degrade biofilms is to match the narrow specificity of enzymes with the large structural diversity of extracellular polymeric substances that hold the biofilm together. In this study, we therefore perform a large-scale screening of single and multi-enzyme formulations to identify combinations of enzymes that most effectively remove dental biofilm.</div><div>We tested &gt;400 different treatment modalities using 44 different enzymes in combinations with up to six enzymes in each formulation, on <em>in vitro</em> biofilms inoculated with human saliva. Mutanase was the only enzyme capable of removing biofilm on its own. Multi-enzyme formulations removed up to 69 % of the biofilm volume, and the most effective formulations all contained mutanase. We shortlisted 10 enzyme formulations to investigate their efficacy against biofilms formed on glass slabs on dental splints worn by 9 different test subjects. Three of the ten formulations removed more than 50 % of the biofilm volume. If optimal enzyme concentration and exposure time can be reached <em>in vivo</em>, these enzyme combinations have potential to be used in novel non-biocidal oral care products for dental biofilm control.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100229"},"PeriodicalIF":5.9,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423191","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":"Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms","authors":"René Wurst,&nbsp;Edina Klein,&nbsp;Johannes Gescher","doi":"10.1016/j.bioflm.2024.100226","DOIUrl":"10.1016/j.bioflm.2024.100226","url":null,"abstract":"<div><div>In bioelectrochemical systems (BES), biofilm formation and architecture are of crucial importance, especially for flow-through applications. The interface between electroactive microorganisms and the electrode surface plays an important and often limiting role, as the available surface area influences current generation, especially for poor biofilm forming organisms. To overcome the limitation of the available electrode surface, nanoparticles (NPs) with a magnetic iron core and a conductive, hydrophobic carbon shell were used as building blocks to form conductive, magnetic micropillars on the anode surface. The formation of this dynamic three-dimensional electrode architecture was monitored and quantified <em>in situ</em> using optical coherence tomography (OCT) in conjunction with microfluidic BES systems. By cyclic voltammetry the assembled three-dimensional anode extensions were found to be electrically conductive and increased the available electroactive surface area. The NPs were used as controllable carriers for the electroactive model organisms <em>Shewanella oneidensis</em> and <em>Geobacter sulfurreducens</em>, resulting in a 5-fold increase in steady-state current density for <em>S. oneidensis</em>, which could be increased 22-fold when combined with Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) aggregates. In the case of <em>G. sulfurreducens</em>, the steady-state current density was not increased, but was achieved four times faster. The study presents a controllable, scalable and easy-to-use method to increase the electrode surface area in existing BES by applying a magnetic field and adding conductive magnetic NPs. These findings can most likely also be transferred to other electroactive microorganisms.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100226"},"PeriodicalIF":5.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423192","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":"Relationship between capsule production and biofilm formation by Mannheimia haemolytica, and establishment of a poly-species biofilm with other Pasteurellaceae","authors":"Yue-Jia Lee ,&nbsp;Dianjun Cao ,&nbsp;Bindu Subhadra ,&nbsp;Cristina De Castro ,&nbsp;Immacolata Speciale ,&nbsp;Thomas J. Inzana","doi":"10.1016/j.bioflm.2024.100223","DOIUrl":"10.1016/j.bioflm.2024.100223","url":null,"abstract":"<div><div><em>Mannheimia haemolytica</em> is one of the bacterial agents responsible for bovine respiratory disease (BRD). The capability of <em>M. haemolytica</em> to form a biofilm may contribute to the development of chronic BRD infection by making the bacteria more resistant to host innate immunity and antibiotics. To improve therapy and prevent BRD, a greater understanding of the association between <em>M. haemolytica</em> surface components and biofilm formation is needed. <em>M. haemolytica</em> strain 619 (wild-type) made a poorly adherent, low-biomass biofilm. To examine the relationship between capsule and biofilm formation, a capsule-deficient mutant of wild-type <em>M. haemolytica</em> was obtained following mutagenesis with ethyl methanesulfonate to obtain mutant E09. Loss of capsular polysaccharide (CPS) in mutant E09 was supported by transmission electron microscopy and Maneval's staining. Mutant E09 attached to polyvinyl chloride plates more effectively, and produced a significantly denser and more uniform biofilm than the wild-type, as determined by crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy with COMSTAT analysis. The biofilm matrix of E09 contained predominately protein and significantly more eDNA than the wild-type, but not a distinct exopolysaccharide. Furthermore, treatment with DNase I significantly reduced the biofilm content of both the wild-type and E09 mutant. DNA sequencing of E09 showed that a point mutation occurred in the capsule biosynthesis gene <em>wecB</em>. The complementation of <em>wecB in trans</em> in mutant E09 successfully restored CPS production and reduced bacterial attachment/biofilm to levels similar to that of the wild-type. Fluorescence in-situ hybridization microscopy showed that <em>M. haemolytica</em> formed a poly-microbial biofilm with <em>Histophilus somni</em> and <em>Pasteurella multocida</em>. Overall, CPS production by <em>M. haemolytica</em> was inversely correlated with biofilm formation, the integrity of which required eDNA. A poly-microbial biofilm was readily formed between <em>M. haemolytica</em>, <em>H. somni</em>, and <em>P. multocida</em>, suggesting a mutualistic or synergistic interaction that may benefit bacterial colonization of the bovine respiratory tract.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100223"},"PeriodicalIF":5.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441125","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":"Salmonella biofilm formation diminishes bacterial proliferation in the C. elegans intestine","authors":"Ines Thiers,&nbsp;Maries Lissens,&nbsp;Hanne Langie,&nbsp;Bram Lories ,&nbsp;Hans Steenackers","doi":"10.1016/j.bioflm.2024.100225","DOIUrl":"10.1016/j.bioflm.2024.100225","url":null,"abstract":"<div><div>Non-typhoidal <em>Salmonella</em> serovars are a significant global cause of foodborne infections, owing their transmission success to the formation of biofilms. While the role of these biofilms in <em>Salmonella</em>'s persistence outside the host is well understood, their significance during infection remains elusive. In this study, we investigated the impact of <em>Salmonella</em> biofilm formation on host colonization and virulence using the nematode model <em>Caenorhabditis elegans</em>. This infection model enables us to isolate the effect of biofilm formation on gut colonization and proliferation, as no gut microbiome is present and <em>Salmonella</em> cannot invade the intestinal tissue of the nematode. We show that a biofilm-deficient Δ<em>csgD</em> mutant enhances gut proliferation compared to the wild-type strain, while the pathogen's virulence, the host's immune signaling pathways, and host survival remain unaffected. Hence, our work suggests that biofilm formation does not significantly contribute to <em>Salmonella</em> infection in <em>C. elegans.</em> However, complementary assays in higher-order <em>in vivo</em> models are required to further characterize the role of biofilm formation during infection and to take into account the impact of biofilm formation on competition with gut microbiome and epithelial invasion.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100225"},"PeriodicalIF":5.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11513601/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142523745","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":"Synergistic combinations of novel polymyxins and rifampicin with improved eradication of colistin-resistant Pseudomonas aeruginosa biofilms","authors":"Johan Storm Jørgensen ,&nbsp;Anne Sofie Laulund Siebert ,&nbsp;Oana Ciofu ,&nbsp;Niels Høiby ,&nbsp;Claus Moser ,&nbsp;Henrik Franzyk","doi":"10.1016/j.bioflm.2024.100224","DOIUrl":"10.1016/j.bioflm.2024.100224","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Background&lt;/h3&gt;&lt;div&gt;Increased prevalence of antimicrobial resistance coupled with a lack of new antibiotics against Gram-negative bacteria emphasize the imperative for novel therapeutic strategies. Colistin-resistant &lt;em&gt;Pseudomonas aeruginosa&lt;/em&gt; constitutes a challenge, where conventional treatment options lack efficacy, in particular for biofilm-associated infections. Previously, synergy of colistin with other antibiotics was explored as an avenue for the treatment of colistin-resistant infections, and recently we reported our efforts towards colistin analogs capable of combating planktonic colistin-resistant strains.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Aims&lt;/h3&gt;&lt;div&gt;The aim of the present study was to investigate whether analogs of polymyxin B with improved potency in wild-type and moderate resistant Gram-negative pathogens would retain similarly increased activity in highly colistin-resistant clinical &lt;em&gt;P. aeruginosa&lt;/em&gt; isolates (in planktonic and biofilm growth) when applied alone and in combination with rifampicin.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Materials and methods&lt;/h3&gt;&lt;div&gt;In this &lt;em&gt;in vitro&lt;/em&gt; study, we tested three analogs of polymyxin B prepared by solid-phase peptide synthesis. Antimicrobial susceptibility testing was performed by measurement of minimum inhibitory concentrations via the broth microdilution method. Interactions between two antimicrobials was quantified in a checkerboard broth microdilution assay by calculating the fractional inhibitory concentration index for each combination. For testing of antibiofilm activity a previously described model with alginate beads encapsulating a biofilm culture was applied. The minimum biofilm eradication concentrations (MBECs) were evaluated, and the fractional biofilm eradication concentration indices were calculated. Three recently identified colistin analogs (CEP932, CEP936 and CEP938) were tested against three isogenic pairs of colistin-susceptible and colistin-resistant &lt;em&gt;P. aeruginosa&lt;/em&gt; clinical isolates as well as the reference strain PAO1.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;For bacteria in planktonic growth CEP938 retained almost full potency in all three resistant isolates, while exhibiting similar activity as colistin in susceptible isolates. Against biofilms CEP938 was slightly more potent against PAO1 as compared to colistin, while also retaining activity against a biofilm of the colistin-resistant strain 41,782/98. Next, synergy between CEP938 and the antibiotic rifampicin was explored. Interestingly, CEP938 did not exhibit synergy with rifampicin in planktonic cultures. Importantly, for colistin-resistant biofilms the CEP938-rifampicin combination demonstrated activity superior to that found for the colistin-rifampicin combination.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusions&lt;/h3&gt;&lt;div&gt;The present study showed &lt;em&gt;in vitro&lt;/em&gt; efficacy of CEP938 against both colistin-susceptible and colistin-resistant &lt;em&gt;P. aeruginosa&lt;/em&gt; biofilms as well as an ability of CEP938 to synergize with rifa","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100224"},"PeriodicalIF":5.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423248","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":"Tolerance of Pseudomonas oleovorans biofilms to disinfectants commonly used in endoscope reprocessing?","authors":"Beata Leeb-Zatorska ,&nbsp;Miriam Van den Nest ,&nbsp;Julia Ebner ,&nbsp;Doris Moser ,&nbsp;Kathrin Spettel ,&nbsp;Lukas Bovier-Azula ,&nbsp;Magda Diab-El Schahawi ,&nbsp;Elisabeth Presterl","doi":"10.1016/j.bioflm.2024.100221","DOIUrl":"10.1016/j.bioflm.2024.100221","url":null,"abstract":"<div><div>Reprocessing failure of endoscopes may result in outbreaks of serious infections in vulnerable patients caused by Gram-negative bacteria. <em>P. oleovorans</em> (PSOL) was detected in 6 automated endoscope washer-disinfectors (AEWDs) in two reprocessing units during routine check and probing for quality control. Ten endoscopes were probed yielding the growth of PSOL. Two different PSOL strains were identified by genotyping. Biofilms and planktonic cells of both PSOL (N = 2) and of <em>Pseudomonas aeruginosa</em> PAO1 as reference were incubated with increased disinfectant concentrations modelling the disinfection process in the AEWD. PSOL in planktonic form was eradicated by GLUT1% (1 g/100 g) at 55 °C. GLUT at a higher concentration of 3 % resulted in the eradication of PSOL biofilms at 25 °C. The persistent growth of PSOL in quality controls indicates inadequate disinfection. Increase of the concentration of GLUT would be an option to eradicate PSOL. However, increasing the concentration of GLUT may lead to corrosion of the sensible instruments and toxic side-effects in patients. Further investigation on disinfectant type and concentration, the reservoir of contamination and defining additional disinfection steps are warranted.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100221"},"PeriodicalIF":5.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423628","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}