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PROVIDER: PRJEB44819 | ENA |
REPOSITORIES: ENA
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Project description:The population phylogenomics of increased virulence and antibiotic resistance in human commensal Escherichia coli over 30 years in France
| PRJEB44872 | ENA
Project description:The population phylogenomics of increased virulence and antibiotic resistance in human commensal Escherichia coli over 30 years in France
| PRJEB44873 | ENA
Project description:Antibiotic resistance is one of the most pressing threats to human health, yet recent work highlights how loss of resistance may also drive pathogenesis in some bacteria. In two recent studies, we found that in vitro beta-lactam antibiotic and nutrient stresses faced during infection selected for the genetic inactivation of the Pseudomonas aeruginosa (Pa) antibiotic efflux pump mexEFoprN. Unexpectedly, efflux pump mutations increased Pa virulence during infection; however, neither the prevalence of efflux pump inactivating mutations in real human infections, nor the mechanisms driving increased virulence of efflux pump mutants were known. We hypothesized that human infection would select for efflux pump mutations that drive increased virulence in Pa clinical isolates. Using genome sequencing of hundreds of Pa clinical isolates, we show that mexEFoprN efflux pump inactivating mutations are enriched in Pa cystic fibrosis isolates relative to Pa intensive care unit clinical isolates. Combining RNA-seq, metabolomics, genetic approaches, and infection models we show that efflux pump mutants increase expression of two key Pa virulence factors, elastase and rhamnolipids, which increased Pa virulence and lung damage during both acute and chronic infections. We show that increased virulence factor production was driven by increased Pseudomonas quinolone signal levels, and this mechanism of increased virulence held true in both a representative ICU clinical isolate and the notorious CF Pa Liverpool epidemic strain. Together, our findings suggest that mutations inactivating antibiotic resistance mechanisms could increase patient mortality and morbidity.
2024-11-12 | MSV000096391 | MassIVE
Project description:The release of cells from S. epidermidis biofilms formed on medical devices has been associated with the onset of bloodstream infections, resulting in increased morbidity and mortality rates. This has to do, in part, with the difficulty to accurately diagnose S. epidermidis bloodstream infections. S. epidermidis is a ubiquitous commensal of human skin and mucosa and, thus, a positive blood culture does not always represent an infection, possibly being the result of contamination during blood collection. As such, there is a high demand to find markers that can help clinicians to distinguish infection (clinical isolates) from contamination (commensal strains). With that in mind, several studies comparing phenotypic or genetic characteristics of clinical and commensal isolates have been performed over the years. However, because S. epidermidis virulence factors seem to be the same that confer its fitness as a commensal, we hypothesized that the ability of S. epidermidis strains to adapt to the host environment may not depend on a specific phenotypic and/or genetic makeup, but rather on the regulation of gene transcription. Thus, using RNA-Sequencing (RNA-seq), we characterized the transcriptome of commensal and clinical isolates in the context of infection to try to uncover differences and, thus, identify markers that could be used for the diagnostics. Several markers with the potential to discriminate between both groups were highlighted. Nevertheless, when the results obtained were confirmed in a wider collection of clinical and commensal isolates the discriminatory power of the genes initially identified was lost. Although we cannot rule out that the characterization of a larger collection of isolates would identify potential candidates, our transcriptomic data was not able to confirm our initial hypothesis, evidencing S. epidermidis opportunistic nature.
2022-12-09 | GSE179407 | GEO
Project description:Antibiotic resistance is exacerbated by the exchange of antibiotic resistance genes (ARGs) between microbes from diverse habitats. Plasmids are important ARGs mobile elements and are spread by horizontal gene transfer (HGT). In this study, we demonstrated the presence of multi-resistant plasmids from inhalable particulate matter (PM) and its effect on gene horizontal transfer. Three transferable multi-resistant plasmids were identified from PM in a hospital, using conjugative mating assays and nanopore sequencing. pTAir-3 contained 26 horizontal transfer elements and 10 ARGs. Importantly pTAir-5 harbored carbapenem resistance gene (blaOXA) which shows homology to plasmids from human and pig commensal bacteria, thus indicating that PM is a media for antibiotic resistant plasmid spread. In addition, 125 μg/mL PM2.5 and PM10 significantly increased the conjugative transfer rate by 110% and 30%, respectively, and augmented reactive oxygen species (ROS) levels. Underlying mechanisms were revealed by identifying the upregulated expressional levels of genes related to ROS, SOS, cell membranes, pilus generation, and transposition via genome-wide RNA sequencing. The study highlights the airborne spread of multi-resistant plasmids and the impact of inhalable PM on the horizontal transfer of antibiotic resistance.
2022-10-31 | GSE159850 | GEO
Project description:In light of the antibiotic crisis, emerging strategies to sensitize bacteria to available antibiotics should be explored. Several studies on the mechanisms of killing suggest that bactericidal antibiotic activity is enforced through the generation of reactive oxygen species (ROS lethality hypothesis). Here, we artificially manipulated the redox homeostasis of the model opportunistic pathogen Pseudomonas aeruginosa using specific enzymes that catalyze either the formation or oxidation of NADH. Increased NADH levels led to the activation of antibiotic efflux pumps and high levels of antibiotic resistance. However, higher NADH levels also resulted in increased intracellular ROS and amplified antibiotic killing. Our results demonstrate that growth inhibition and killing activity are mediated via different mechanisms. Furthermore, the profound changes in bioenergetics produced low virulence phenotypes characterized by reduced inter-bacterial signaling controlled pathogenicity traits. Our results pave the way for a more effective infection resolution and add an anti-virulence strategy to maximize chances to combat devastating P. aeruginosa infections while reducing the overall use of antibiotics.
2021-11-17 | GSE188801 | GEO
Project description:Staphylococcus haemolyticus is a skin commensal emerging as an opportunistic pathogen. Nosocomial isolates of S. haemolyticus are the most antibiotic resistant members of the coagulase negative staphylococci (CoNS), but information about other S.haemolyticus virulence factors is scarce. Bacterial virulence is mediated by membrane vesicles (MVs) which enable secretion and long distance delivery of bacterial effector molecules while protecting the cargo from proteolytic degradation from the environment. We wanted to determine if the MV protein cargo of S.haemolyticus is strain specific and enriched in certain MV associated proteins compared to the totalsecretome. The present study shows that both clinical and commensal S. haemolyticus isolates produce membrane vesicles. The MV cargo of both strains was enriched in proteins involved in adhesion and in acquisition of iron. The MV cargo of the clinical strain was further enriched in antimicrobial resistance proteins.
2018-11-30 | PXD010389 | Pride
Project description:Evolution of invasive Streptococcus pneumoniae PMEN3 clone over 30 years in Barcelona, Spain
| PRJEB24965 | ENA
Project description:The mammalian gut is inhabited by a large and complex microbial community that lives in a mutualistic relationship with its host. Innate and adaptive mucosal defense mechanisms ensure a homeostatic relationship with this commensal microbiota. Secretory antibodies are generated from the active polymeric Ig receptor (pIgR)-mediated transport of IgA and IgM antibodies to the gut lumen and form the first line of adaptive immune defense of the intestinal mucosa. We probed mucosal homeostasis in pIgR knockout (KO) mice, which lack secretory antibodies. We found that in pIgR KO mice, colonic epithelial cells, the cell type most closely in contact with intestinal microbes, differentially expressed (>2-fold change) more than 200 genes compared with wild type mice, and upregulated the expression of anti-microbial peptides in a commensal-dependent manner. Detailed profiling of microbial communities based on 16S rRNA genes revealed differences in the commensal microbiota between pIgR KO and wild type mice. Furthermore, we found that pIgR KO mice showed increased susceptibility to dextran sulfate sodium (DSS)-induced colitis, and that this was driven by their conventional intestinal microbiota. In conclusion, secretory antibodies or the pIgR itself are required to maintain a stable commensal microbiota. In the absence of these humoral effector components, gut homeostasis is disturbed and the outcome of colitis significantly worsened. 4 groups: wild type mice treated with antibiotic (5 replicates), wild type mice left untreated (5 replicates), pIgR KO mice treated with antibiotic (6 replicates), and pIgR KO mice left untreated (6 replicates).
2013-12-28 | E-GEOD-34630 | biostudies-arrayexpress
Project description:The most clinically relevant risk factor for Clostridioides difficile-associated disease (CDAD) is recent antibiotic treatment. Though most broad-spectrum antibiotics significantly disrupt the structure of the gut microbiota, only particular ones increase CDAD risk, suggesting additional factors might increase the risk from certain antibiotics. Here we show that commensal-independent effects of antibiotics collectively prime an in vitro germ-free human gut for CDAD. We found a marked loss of mucosal barrier and immune function with CDAD-associated antibiotic pretreatment distinct from pretreatment with an antibiotic unassociated with CDAD, which did not reduce innate immune or mucosal barrier functions. Importantly, pretreatment with CDAD-associated antibiotics sensitized mucosal barriers to C. difficile toxin activity in primary cell-derived enteroid monolayers. These data implicate commensal-independent host changes in the increased risk of CDAD with specific antibiotics. Our findings are contrary to the previously held belief that antibiotics allow for CDAD solely through disruption of the microbiome. We anticipate this work to suggest potential avenues of research for host-directed treatment and preventive therapies for CDAD, and to impact human tissue culturing protocols.
2019-08-06 | GSE135383 | GEO