Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
Project description:OXA-427 is a new class D carbapenemase encountered in different species of Enterobacteriaceae in a Belgian hospital. To study the dispersal of this gene, we performed a comparative analysis of two plasmids containing the blaOXA-427 gene, isolated from a Klebsiella pneumoniae strain and an Enterobacter cloacae complex strain. The two IncA/C2 plasmids containing blaOXA-427 share the same backbone; in the K. pneumoniae strain, however, this plasmid is cointegrated into an IncFIb plasmid, forming a 321-kb megaplasmid with multiple multiresistance regions.
Project description:BACKGROUND:Bacterial isolates with multiple plasmids harbouring different carbapenemase genes have emerged and been identified repeatedly, despite a general notion that plasmids confer fitness cost in bacterial host. In this study, we investigated the effects of plasmids with carbapenemase genes on the fitness and virulence of bacteria. METHODS:Different plasmids harbouring the carbapenemase genes, blaNDM-1 and blaOXA-232, were isolated from a carbapenem-resistant K. pneumoniae strain. Each plasmid was conjugated into the Escherichia coli strain DH5?, and a transconjugant with both plasmids was also obtained by transformation. Their in vitro competitive ability, biofilm formation, serum resistance, survival ability within macrophage and fruit fly, and fly killing ability were evaluated. RESULTS:The transconjugants with a single plasmid showed identical phenotypes to the plasmid-free strain, except that they decreased fly survival after infection. However, significantly increased fitness, virulence and biofilm production were observed consistently for the transconjugant with both plasmids, harbouring blaNDM-1 and blaOXA-232. CONCLUSIONS:Our data indicate that bacteria carrying multiple plasmids encoding different carbapenemases may have increased fitness and virulence, emphasizing the need for diverse strategies to combat antimicrobial resistance.
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.
Project description:The increasing resistence and/or bacterial tolerance to bactericides, such as chlorhexidine, causes worrisome public health problems. Using transcriptomical and microbiological studies, we analysed the molecular mechanisms associated with the adaptation to chlorhexidine in two carbapenemase-producing strains of Klebsiella pneumoniae belonging ST258-KPC3 and ST846-OXA48.
Project description:To describe an outbreak due to an extensively drug-resistant Klebsiella pneumonia harbouring blaNDM-1 and/or blaOXA-48 in Barcelona (2015-2017)