PHENOTYPIC AND GENOTYPIC CHARACTERISATION OF CARBAPENEM RESISTANT Klebsiella pneumoniae CLINICAL ISOLATES FROM A TERTIARY CARE HOSPITAL

Background: The evolution of multidrug resistant Klebsiella pneumoniae is a global threat in treating nosocomial infections. Carbapenem resistant Klebsiella pneumoniae (CRKP) are a group of emerging highly drug-resistant Gram-negative bacilli that produces class A, B and D beta lactamases which help in hydrolyzing carbapenems thereby warranting alternate drug therapy. This study was aimed to determine the prevalence of CRKP phenotypically and genotypically.

Methods: The identification and antibiotic susceptibility testing of K. pneumoniae isolates were performed by vitek 2 systems version 7.0 as per CLSI guidelines. Phenotypic detection of carbapenemase was performed by combined-disc test using meropenem alone and with both phenyl boronic acid and EDTA. Genotypic detection was performed by multiplex PCR and conventional PCR. The blaKPC, blaNDM, blaOXA-48, blaIMP, blaVIM, blaSPM, blaGIM and blaSIM genes were screened.

Results: The MIC value obtained for carbapenems by vitek 2 showed carbapenem resistance in 19 isolates. All these isolates were positive phenotypically. While, only 11 isolates were positive genotypically showing blaNDM (n=2), blaOXA-48 (n=7) and blaIMP (n=4) gene. All the isolates were susceptible to colistin. Most of the isolates were resistant to cephalosporins and significant resistance to tigecycline was also observed.

Conclusion: The emergence and spread of CRKP is a global threat which hampers the effective control of infections particularly in developing countries. The present study has shown a low prevalence (9.09%) of carbapenem resistance. However the resistance of clinically isolated carbapenem resistant strains can primarily be ascribed to production of carbapenemases there are also other mechanisms like deletion of OMP proteins, production of beta lactamases like ESBL or AmpC contributing significantly. Judicious use of antibiotics and surveillance to detect CRKP strains early will help in reducing the spread of such strains.