Abstract

ISOLATION, IDENTIFICATION AND MOLECULAR CHARACTERIZATION OF THE CARBAPENEMASE PRODUCING GRAM-NEGATIVE BACILLI

Bagré Issa*, Gaurav Kumar, Debasish Kar and Anindya S. Ghosh

Abstract

The emergence and spread of Carbapenemase-Producing Enterobacteriaceae (CPE) has been identified as a public health threat, especially since recent studies on CPE and Carbapenem-Non- Susceptible Enterobacteriaceae (CNSE) have shown that infection or colonization has been associated with higher in-hospital mortality. The identification of Carbapenemase-producing Gram-negative bacilli (GNB) is mandatory, as they may cause severe infections, and carbapenems (imipenem - IMP and meropenem - MER) are the therapy of choice in many nosocomial infections. The objectives of the present study are the Isolation, identification and molecular characterization of the carbapenemase producing Gram-positive Bacilli. Six Gramnegative bacilli isolated in biological material cultures and Four E. coli strains were tested by disk-diffusion (Himedia) for DOR, MER, and IMP in Mueller-Hinton agar (Himedia). The interpretation criteria applied were those suggested by CLSI. All positive strains were subsequently analysed by PCR method using four different primers. Minimals Inibitory Concentrations (MICs) were determined by a broth macrodilution method with Mueller- Hinton broth (Himedia) and containing bacterial inoculum of 107 CFU per tube as per CLSI guidelines. All the six isolates of our study displayed resistance against carbapenem while E. coli control strains were observed to be sensitive against carbapenem. All the six isolates contain at least the NDM gene as the carbapemen resistance gene.

Keywords: Carbapenemase, Carbapenem, Gram-negative Bacilli, PCR.