Prevalence of Extended Spectrum Beta Lactamase (ESBL) Producing Gram Negative Bacilli from various clinical isolates

Abstract

Rapid emergence of ESBL production in GNB has put forward a major challenge in their detection as well as treatment options. Therefore for proper management of these resistant bacteria it is very important and necessary to correctly identify them. Aim: To know the prevalence of ESBL producing GNBs in all clinical isolates received in the Microbiology Laboratory of GMCH Aurangabad. Method: The study was conducted from June 2008 to July 2009. Our study group included 711 GNB,s identified by Grams staining, colony morphology and biochemical reactions. AST was done on MHA by Kirby Beurs disc diffusion method. All the organisms suspected of producing ESBL by the CLSI screening criteria were confirmed by the phenotypic confirmatory disc diffusion test (PCDDT). Result: Out of the 711 GNB tested, 433(61%) were found to be ESBL positive by the PCDDT method. The different GNB's identified were Klebsiella pneumoniae (47%) E. coli (23%), Pseudomonas spp. (21.37%), etc. ESBL production was most common in Klebsiella pneumoniae (74%), followed by E. coli (62%), Enterobacter spp. (60%) etc. Imepenem showed the highest rate of sensitivity (97%). Conclusion: Since ESBL producing GNBs are on a constant rise, it is very necessary to test all the organisms for ESBL production by the screening and confirmatory methods. Spread of these ESBL producers should be prevented by infection control policy and empirical use of antibiotics.