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:New and rapid antimicrobial susceptibility/resistance testing methods are required for bacteria from positive blood cultures. In the current study we developed and evaluated a targeted LC-MS/MS assay for the detection of beta-lactam, aminoglycoside and fluoroquinolone resistance mechanisms in blood cultures positive for E. coli or K. pneumoniae. Selected targets were the beta-lactamases SHV, TEM, OXA-1-like, CTX-M-1-like, CMY-2-like, chromosomal E. coli AmpC, OXA-48-like, NDM, VIM and KPC, the aminoglycoside modifying enzymes AAC(3)-Ia, AAC(3)-II, AAC(3)-IV, AAC(3)-VI, AAC(6’)-Ib, ANT(2”)-I and APH(3’)-VI, the 16S-RMTases ArmA, RmtB, RmtC and RmtF, the quinolone resistance mechanisms QnrA, QnrB, AAC(6’)-Ib-cr, the wildtype QRDR of GyrA, and for E. coli, the porins OmpC and OmpF. The developed assay was evaluated using 100 prospectively collected positive blood cultures, 100 negative blood cultures inoculated with isolates that were previously collected from blood cultures, and 48 isolates inoculated with isolates carrying genes of less prevalent resistance mechanisms.
Project description:The emergence and spread of polymyxin resistance, especially among Klebsiella pneumoniae isolates threaten the effective management of infections. This study profiled for polymyxin resistance mechanisms and investigated the activity of polymyxins plus vancomycin against carbapenem- and polymyxin-resistant K. pneumoniae.
Project description:The increasing antibiotic resistance of Klebsiella pneumoniae poses a serious threat to global public health. To investigate the antibiotic resistance mechanism of Klebsiella pneumonia, we performed gene expression profiling analysis using RNA-seq data for clinical isolates of Klebsiella pneumonia, KPN16 and ATCC13883. Our results showed that mutant strain KPN16 is likely to act against the antibiotics through increased increased butanoate metabolism and lipopolysaccharide biosynthesis, and decreased transmembrane transport activity.