Microbiology-Sgm最新文献

{"title":"Investigation of minocycline and hyaluronic acid combined with ultrasound therapy in a <i>Staphylococcus aureus</i>-infected rat wound model.","authors":"Yu Gou, Yi Zhang, Liangjia Bi, Jiapin Zou, Dian Yu, Deshu Zhuang","doi":"10.1099/mic.0.001612","DOIUrl":"10.1099/mic.0.001612","url":null,"abstract":"<p><p>This study aimed to examine the effects of minocycline (MINO) and hyaluronic acid (HA) on wound healing in rats. MINO/HA was combined with ultrasound therapy for treating wounds infected with <i>Staphylococcus aureus</i>. Cutaneous wounds in 40 female Wistar rats were infected with <i>S. aureus</i> and then randomly divided into four groups: infected-wounded skin treated with sterile saline solution (control group), treated with ultrasound (ultrasound group), treated by a mixture of MINO and HA (MINO+HA group) and treated with a mixture of MINO and HA combined with ultrasound (MINO+HA+ultrasound group). General observations of the wound healing were photographed. After three treatments, bacterial counts were obtained to determine antibacterial efficacy and wound healing was assessed by histological analysis and evaluation of inflammatory cytokine levels (TNF-<i>α</i> and IL-1<i>β</i>) by immunohistochemistry. Compared with the control group, both the MINO+HA group and the MINO+HA+ultrasound group achieved a significant wound square reduction of 43.7% and 54.9 %, respectively (<i>P</i><0.001). A small number of inflammatory cells, organization of collagen fibres and maturation of granulation tissue were observed in the histological evaluation of the MINO+HA+ultrasound group. The expression levels of TNF-<i>α</i> and IL-1<i>β</i> in the MINO+HA+ultrasound group were decreased compared to both the control group and the MINO+HA group (<i>P</i><0.001). These findings revealed the possibility of using a mixture of MINO and HA combined with ultrasound to minimize inflammation and promote tissue regeneration during the treatment of wound infections.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12507120/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145253491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MmpL12 transports lipooligosaccharides and impacts virulence in <i>Mycobacterium marinum</i>.","authors":"Rebeca Bailo, C M Santosh Kumar, Albel Singh, Peter A Lund, Vassiliy N Bavro, Apoorva Bhatt","doi":"10.1099/mic.0.001618","DOIUrl":"https://doi.org/10.1099/mic.0.001618","url":null,"abstract":"<p><p>Lipooligosaccharides (LOSs) are polar glycolipids found in the cell envelope of many pathogenic mycobacteria. Here, we show that LOS transport in <i>Mycobacterium marinum</i> requires <i>mmpL12</i>, a member of the resistance-nodulation-division family of membrane proteins. Deletion of <i>mmpL12</i> resulted in a rough colony morphology and increased hydrophobicity. The △<i>mmpL12</i> mutant accumulated three of the biosynthesis intermediates of LOSs (LOS-I, LOS-II and LOS-III) intracellularly and failed to produce the final product, LOS-IV, suggesting that final glycosylation of LOS-III to yield LOS-IV occurs extracellularly after LOS-III export. <i>In silico</i> structural analysis of the MmpL12 suggests that it is a proton-driven transporter that shares very similar organization with other subclass 1 MmpLs (MmpL1, 2, 4-8 and 9-10), featuring a large periplasmic loop (PD3 domain) which is predicted to form a large coiled coil that may be involved in the trimerization of this subset of MmpL transporters. Furthermore, the long C-terminal extension domain, which is unique to MmpL12, may provide additional trimerization support and scaffold for assembly of additional LOS biosynthetic enzymes. The absence of any extracellular LOS intermediates and of LOS-IV had an impact on virulence, with the mutant strain exhibiting a larger bacterial burden in infected zebrafish embryos.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145253402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of <i>Pseudomonas aeruginosa</i> infection on the airway metabolome.","authors":"Angharad E Green, Dilem Ruhluel, Marie Phelan, Joanne L Fothergill, Daniel R Neill","doi":"10.1099/mic.0.001617","DOIUrl":"https://doi.org/10.1099/mic.0.001617","url":null,"abstract":"<p><p><i>Pseudomonas aeruginosa</i> is an environmentally resilient bacterium and an important cause of both acute and chronic infections in people with impaired natural barriers or immunological defences. Chronic respiratory infection with <i>P. aeruginosa</i> is a major cause of morbidity and mortality in people with airway diseases, including cystic fibrosis (CF) and non-CF bronchiectasis. Chronic airway infection is characterized by periods of relative stability punctuated by pulmonary exacerbations, during which times rapid bacterial outgrowth necessitates intense antimicrobial chemotherapy. The periods of stable infection can be modelled in mice by nasal instillation of airway-adapted <i>P. aeruginosa</i> in saline, leading to prolonged colonization of both upper airway (sinus) and lower airway (lung) environments that is not associated with symptomatic disease. Here, we use NMR metabolomics to investigate the impact of <i>P. aeruginosa</i> colonization on the metabolic landscape of sinuses and lungs. Lung infection led to pronounced changes in the airway metabolome, with significant depletion of glucose and myo-inositol but enrichment of glutathione (GSH), relative to uninfected lungs. Changes in the sinuses were more subtle but could be identified through dimensionality reduction approaches. The NMR spectral peaks that discriminated between infected and uninfected sinuses in partial least squares discriminant analysis included those for lactate and choline but were mostly representative of yet unidentified metabolites. These data highlight the differential impact of infection on separate airway compartments and identify undefined metabolites undergoing pronounced abundance changes during infection.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145253398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of AprA and pyocyanin from <i>Pseudomonas aeruginosa</i> on <i>Staphylococcus aureus</i> tolerance to silver.","authors":"Jakob Gorodetsky, Nadia Monych, Raymond J Turner, Omid Haji-Ghassemi, Sean C Booth","doi":"10.1099/mic.0.001596","DOIUrl":"10.1099/mic.0.001596","url":null,"abstract":"<p><p>The opportunistic pathogens <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> are often found together causing persistent infections where they exhibit complex interactions that affect their virulence and resistance to treatment. We sought to clarify how interactions between these organisms affect their resistance to the antimicrobial metal silver (AgNO₃). As previous work showed that cell-free supernatant from <i>P. aeruginosa</i> enhances the resistance of <i>S. aureus,</i> we aimed to identify the exact factor(s) responsible for this increase. Using molecular weight cutoff filters and proteomics, we identified the protein AprA and pyocyanin as the responsible factors. Transposon-mediated disruption of <i>aprA</i> led to the production of supernatant which could not enhance the silver tolerance of <i>S. aureus</i>. These findings suggest that the protease AprA from <i>P. aeruginosa</i> plays an important role in increasing the tolerance of <i>S. aureus</i> to AgNO₃ via in part by mediating the levels of pyocyanin which in turn reduces Ag²⁺ to detoxify it.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12408190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144976378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic-di-GMP signalling mutants drive ecological succession and self-generated diversity in experimentally evolved biofilms of <i>Pseudomonas aeruginosa</i>.","authors":"Gregory J Wickham, Chuanzhen Zhang, Ryan Sweet, Maria Solsona-Gaya, Mark A Webber","doi":"10.1099/mic.0.001605","DOIUrl":"10.1099/mic.0.001605","url":null,"abstract":"<p><p>Biofilms represent a discrete form of microbial life which are physiologically distinct from free-living planktonic cells. The altered phenotypic manifestations of the biofilm may also elicit lifestyle-dependent adaptive responses to selective pressures. In this work, an experimental evolution model was used to study the adaptation to a biofilm lifestyle in <i>Pseudomonas aeruginosa</i> PA14. The serial passage of biofilms selected for biofilm hyperproduction in a stepwise fashion characterized by increased biomass production and phenotypic diversification was not associated with reduced susceptibility to antibiotics. Adaptation to a biofilm lifestyle selected for mutations causes constitutive increases of intracellular c-di-GMP concentrations via mutations in the phosphodiesterase <i>dipA</i>, the <i>yfiBNR</i> signalling complex and the bifunctional diguanylate cyclase/phosphodiesterase <i>morA</i>. Furthermore, selection for biofilm hyperproduction also gave rise to self-generated diversity by eliciting morphotypic diversification into complex community structures. Individual morphotypes were not associated with specific mutations and lineages dynamically switched between morphotypes despite possessing conserved mechanisms of biofilm hyperproduction. This work provides insights into the evolutionary importance of self-generated diversity to the biofilm and reveals the genetic control and phenotypic dynamics which contribute to the characteristically rugged fitness landscape associated with a sessile lifestyle.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12440571/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145070982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chromosomal resistance mutations facilitate acquisition of multidrug-resistant plasmids in <i>Escherichia coli</i>.","authors":"Khadija-Siddiqa N Hanga, Michael A Brockhurst, Michael J Bottery","doi":"10.1099/mic.0.001599","DOIUrl":"10.1099/mic.0.001599","url":null,"abstract":"<p><p>Bacteria can gain multiple resistance mechanisms in a single step by the acquisition of multidrug-resistant (MDR) plasmids, but it is unclear how antibiotic selection during the acquisition of MDR plasmids affects the evolution of additional resistance mechanisms. Through conjugating separate extended-spectrum <i>β</i>-lactamase (ESBL)- and carbapenemase-producing MDR plasmids into plasmid-naive <i>Escherichia coli</i> hosts, we examine the effects of acquisition of a single plasmid or co-acquisition of multiple plasmids upon fitness costs, resistance and subsequent genomic adaptation. We show that acquisition of pOXA-48, encoding OXA-48 carbapenemase, is associated with highly variable fitness costs and levels of resistance to ertapenem in transconjugants independent of the presence of pLL35. This phenomenon was not observed during the acquisition of ESBL CTX-M-15-encoding pLL35 alone. Within a single growth cycle, transconjugants receiving pOXA-48 rapidly gained parallel mutations affecting the membrane porin OmpF, or its regulators OmpR or EnvZ. These chromosomal mutations were not compensatory for the fitness costs imposed by the plasmid, nor did they provide significant increases in resistance to carbapenems in the absence of the pOXA-48. Rather, they acted synergistically with the plasmid-encoded carbapenemase, which alone only provided marginal resistance, together providing high-level resistance to ertapenem. Such rapid evolutionary processes may play an important role in plasmid dynamics within environments with strong antibiotic selection for plasmid-encoded antimicrobial resistance genes (ARGs), particularly when these ARGs provide only marginal resistance.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145138800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors affecting CRISPR-Cas defense against antibiotic resistance plasmids harboured by <i>Enterococcus faecalis</i> laboratory model strains and clinical isolates.","authors":"Tahira Amdid Ratna, Belle Marco Sharon, Cesar Alejandro Barros Velin, Kelli Palmer","doi":"10.1099/mic.0.001601","DOIUrl":"10.1099/mic.0.001601","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> is a Gram-positive bacterium and opportunistic pathogen that acquires resistance to a wide range of antibiotics by horizontal gene transfer (HGT). The rapid increase of multidrug-resistant (MDR) bacteria including MDR <i>E. faecalis</i> necessitates the development of alternative therapies and a deeper understanding of the factors that impact HGT. CRISPR-Cas systems provide sequence-specific defense against HGT. From previous studies, we know that <i>E. faecalis</i> CRISPR-Cas provides sequence-specific anti-plasmid defense during agar plate biofilm mating and in the murine intestine. Those studies were mainly conducted using laboratory model strains with a single, CRISPR-targeted plasmid in the donor. MDR <i>E. faecalis</i> typically possess multiple plasmids that are diverse in sequence and may interact with each other to impact plasmid transfer and CRISPR-Cas efficacy. Here, we altered multiple parameters of our standard <i>in vitro</i> conjugation assays to assess CRISPR-Cas efficacy, including the number and genotype of plasmids in the donor, and laboratory model strains as donor versus recent human isolates as donor during conjugation. We found that the plasmids pTEF2 and pCF10, which are not targeted by CRISPR-Cas in our recipient, enhance the conjugative transfer of the CRISPR-targeted plasmid pTEF1 into both WT and CRISPR-Cas-deficient (via deletion of <i>cas9</i>) recipient cells. However, the effect of pTEF2 on pTEF1 transfer is much more pronounced, with a striking 6-log increase in pTEF1 conjugation frequency when pTEF2 is also present in the donor and recipients are deficient for CRISPR-Cas (compared with 4-log for pCF10). Overall, this study provides insight about the interplay between plasmids and CRISPR-Cas defence, opening avenues for developing novel therapeutic strategies to curb HGT among bacterial pathogens and highlighting pTEF2 as a plasmid for additional mechanistic study.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12476151/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145126300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Enterococcus faecalis</i> requires unsaturated fatty acids to overcome toxicity of environmental saturated fatty acids.","authors":"Qi Zou, Huijuan Dong, John E Cronan","doi":"10.1099/mic.0.001602","DOIUrl":"10.1099/mic.0.001602","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> synthesizes phospholipids from either <i>de novo</i> synthesized or exogenous fatty acids. However, environmental saturated fatty acids are toxic to <i>E. faecalis</i>. The mechanism of toxicity is unknown. We report that saturated acids block growth by efficiently repressing transcription of the fatty acid biosynthesis (<i>fab</i>) genes, resulting in blockage of the synthesis of unsaturated fatty acyl chains. Saturated fatty acid toxicity depends on the chain length of the acyl chains. Growth was restored in the presence of toxic saturated fatty acids by the increased <i>de novo</i> unsaturated fatty acid synthesis, resulting from the deletion of the <i>fabT</i> gene, the repressor that regulates (<i>fab</i>) gene transcription. The addition of unsaturated fatty acids to the medium also restored growth in the presence of toxic saturated fatty acids. Overexpression of AcpA, the fatty acid synthesis acyl carrier protein, also gave increased <i>de novo</i> synthesis of unsaturated fatty acids and restored growth.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12408189/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144976383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Common food preservatives induce an oxidative stress response in <i>Salmonella enterica</i> serovar Typhimurium.","authors":"Emma R Holden, Joshua C I Horton, Mark A Webber","doi":"10.1099/mic.0.001609","DOIUrl":"10.1099/mic.0.001609","url":null,"abstract":"<p><p>Despite their frequent use, the mechanisms of action of common food preservatives are poorly understood. As there is a drive to develop alternative preservatives, understanding the mechanisms of action of current preservatives can inform the development of novel food preservatives to ensure their efficacy. Here, we used TraDIS-<i>Xpress</i>, a large-scale, genome-wide unbiased screen to determine the mechanisms of action of common food preservatives by determining the genes that affect preservative susceptibility in <i>Salmonella enterica</i> serovar Typhimurium. We identified genes associated with central metabolism and oxidative stress responses that were important for all four preservatives. Formate dehydrogenase activity and synthesis was crucial for survival in the presence of both sodium chloride and potassium chloride. We found some preservative-specific effects on pathogen susceptibility, for example, LPS synthesis which improved survival upon exposure to sodium nitrite but harmed survival when exposed to sodium chloride or potassium chloride. This research expands our understanding of how some current preservatives act and can inform the effective use of preservatives in current and emerging food products to ensure high standards of food safety.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12440568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145070903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disulphide bond-forming enzymes in clostridial species.","authors":"Claudia Antonika, Jocelyne Mendoza, Cristina Landeta","doi":"10.1099/mic.0.001603","DOIUrl":"10.1099/mic.0.001603","url":null,"abstract":"<p><p>Disulphide bond formation is critical for the folding and stability of proteins involved in bacterial cell envelope processes yet remains understudied in clostridial pathogens. While a few Clostridia-derived toxins and virulence factors are known to depend on disulphide bonds, the enzymes catalysing their formation are poorly characterized. Here, we performed a bioinformatic search to identify ten putative disulphide bond-forming enzymes in Clostridia. We cloned and codon-optimized these genes, testing their ability to complement <i>Escherichia coli dsb</i> mutants. Our analysis revealed a VKOR homologue, a VKOR-DsbA fusion and three DsbA homologues capable of complementing <i>E. coli dsb</i> mutants. Notably, <i>Clostridium botulinum</i> DsbA functioned independently of a regenerating partner, with its activity recycled by glutathione disulphide or ergothioneine. In contrast, <i>Clostridium tetani</i> and <i>Clostridioides difficile</i> DsbA proteins required <i>E. coli</i> DsbB for regeneration, suggesting reliance on distinct thiol or enzyme partners. Understanding oxidative protein folding in Clostridia could reveal new targets for antibacterial intervention.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12453122/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145056230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}