Detection of carbapenem resistant enterobacteriaecae and the comparison between phenotypic methods and multiplex PCR

Abstract

Introduction: Carbapenem resistant Enterobacteriacea (CRE) has created a remarkable health distress. Definitive detection of Carbapenemase producing CRE is the first step in combating this problem. Objective: To detect and compare CP- CRE both by phenotypic and molecular methods. Materials and Methods: A total of 52 carbapenem resistant clinical isolates were screened for the presence of carbapenemase genes by routine phenotypic methods like modified hodge test and combined disc test as well by multiplex PCR. Results: Out of the total 52 meropenem resistant isolates, 35 were modified hodge test positive and 33 were combined disc test positive. 42 isolates were found harbouring one or more than one gene. blaKPC alone was present in 38 isolates, while as blaKPC with blaNDM were present in 1 isolate and blaKPC with blaIMP was seen in 1 isolate. blaNDM alone in 2 isoates, blaIMP and blaVIM alone in none of the isolates. Conclusion: Accurate detection of carbapenemase producing genes by molecular methods overcomes the problem related to CRE. Though there is no signal method that is ideal for all situations. Keywords: Modified hodge test, Combined disc test, Multiplex PCR, Carbapenem resistant Enterobacteriaecae.