The emergence of plasmid mediated quinolone resistance qnrA2 in extended spectrum β-lactamase producing Klebsiella pneumoniae in the Middle East

Abstract

Background: Klebsiella pneumoniae is one of the most important opportunistic pathogens causing serious complications in patients in hospitals and community. The clinical significance of K. pneumoniae is mainly due to its ability to acquire multiple antibiotic resistance genes. In this study we report the findings of a survey of plasmid mediated quinolone resistance in Extended-Spectrum β-lactamase (ESBL)-producing K. pneumoniae in Kuwait. Methods: Clinical samples were collected from the microbiology laboratories of three major hospitals. Isolates were confirmed as ESBL-producers by disc diffusion method and PCR for the presence of bla genes. Antimicrobial susceptibility testing and genetic analysis were performed to detect the presence of a number of genes conferring resistance to β-lactam and fluoroquinolone antimicrobial agents including blaSHV, blaTEM, aac (6′)-Ib-cr, qnrA, qnrB and qnrS. Pulsed-field gel electrophoresis (PFGE) was used for typing the isolates. Results: In total 173 ESBL-producing K. pneumoniae were detected. qnr genes were identified in 27 (15.6 %) isolates and aac(6′)-Ib Ib-cr gene in 26 (96 %). One (3.7 %) contained qnrA2, 21 harbored qnrB1 (78 %) and 5 (18.5 %) contained qnrS. Twenty one (78 %) isolates contained all three bla genes. PFGE showed diverse profiles. Conclusion: We identified for the first time the emergence of the mobile fluoroquinolone resistance qnrA2 in a clinical isolate in the middle east and also showed the dissemination of aac (6′)-Ib-cr, qnrB, and qnrS genes among ESBL-producing K. pneumoniae in Kuwait. The abundance of plasmid mediated resistance to fluoroquinolones among ESBL-producing K. pneumoniae is alarming as it facilitates therapy failure. Preventing the spread of these isolates is crucial if we are to sustain the effectiveness of the limited choices we have left in antimicrobial therapy.