Detection and Molecular Typing of Extended Spectrum Beta Lactamases (ESBLs) Producing Gram-Negative Bacteria from Wound Infections

Abstract

ABSTRACT: Extended spectrum β-lactamases (ESBLs) producing bacteria, which are mainly Gram-negative, have emerged as a major threat in recent years as they are resistant to most antimicrobials. This study was conducted to investigate the prevalence of ESBL producing Gram-negative bacteria in woundinfections and to map their antimicrobial resistance profile. A total of 100 samples were collected and identified from infected wounds. The Gram-negative bacteria were checked for identification as ESBL producers by using double disc diffusion test. The identified ESBL producers were subjected to PCR basedtyping of ESBLs. Out of 100 collected infected wound samples, 69 Gram-negativebacteria were isolated. The isolated pathogens were: Klebsiella pneumoniae (45%), Escherichia coli(29%), Enterobacter(10%), Proteus spp (9%) and Pseudomonas aeruginosa(7%).Twenty eight (40%) isolates were detected as ESBLproducers The ESBL producers were subjected to molecular analysis that showed CTX-M (82%) as most prevalent enzyme type responsible for ESBL production. One E. coli and one Proteus isolate was identified as GES and PER type ESBL producer respectively, where as one of the E. coli isolates was found to harborboth CTX-M and GES type ESBLs. TEM and OXA types were not found in any of the isolates. All ESBL producers showed multidrug resistance for eleven antimicrobials. Klebsiella (40%) was identified as the most prevalent ESBL producer followed by E. coli (35%). Most dominant ESBL type identified by PCR wasCTX-M and Klebseilla pneumoniae (83.3%) and E. coli (100%) were the dominant CTX-M type ESBL producers.