Molecular Profile of Emerging Multidrug Resistant Klebsiella pneumoniae Clinical Isolates from Southern India

Abstract

Introduction: Multidrug Resistance (MDR) in Klebsiella pneumoniae isolates is an increasingly recognised threat to hospital infection control. It is known to produce a wide array of cephalosporinase and carbapenemase enzymes. Aim: This study was done to determine the prevalence of MDR in K. pneumoniae with phenotypic and genotypic characterisation of Extended Spectrum Beta-Lactamase (ESBL), AmpC and carbapenemase mediated resistance mechanisms. Materials and Methods: Out of 562 K. pneumoniae isolates recovered during November 2014 to June 2015 in our tertiary care hospital in Pondicherry, 117 MDR strains were phenotypically analysed for presence of various types of beta lactamases and carbapenemases by ceftazidime-clavulanic acid combined disc test, AmpC disc test, Modified Hodge's test and meropenemEDTA combined disc test. These isolates were further screened for ESBL (blaCTX-M, blaSHV-1, blaTEM) and Carbapenemase genes (blaNDM-1, blaIMP-1, blaVIM-2, blaSIM-1 and blaKPC) by multiplex PCR. Results: Prevalence of MDR strains of K. pneumoniae was 20.8%. Out of 117 MDR K. pneumoniae, ESBL, AmpC and MBL mediated resistance was identified by phenotypic method in 91, 27 and 16 isolates respectively. Among the ESBL and MBL genes, blaCTX-M (60.6%), blaSHV-1 (69%), blaNDM-1 (33%) and blaIMP-1 (9%) genes were detected. Co-production of multiple enzymes was observed in 32% isolates. Conclusion: Beta-lactam hydrolysing enzymes are prevalent among MDR K. pneumoniae stains in our region. Co-expression of ESBL and MBL genes are found in a large proportion of clinical isolates of K. pneumoniae.

Keywords

• extended spectrum beta-lactamase gene
• metallo beta-lactamase gene
• molecular characterisation