Prevalence and Molecular Epidemiology of Clinical Isolates of and Harboring Extended-Spectrum Beta-Lactamase and Carbapenemase Genes in Bangladesh.

Spread of Gram-negative bacteria producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases constitutes a growing challenge in control of bacterial infections. In this study, prevalence and genetic characteristics of and harboring ESBL and/or carbapenemase genes, with other beta-lactamase/resistance genes, were investigated for a total of 375 clinical isolates in Mymensingh located in north-central Bangladesh. The major ESBL gene was group, which was detected in 33.9% and 51.4% of and , respectively, with CTX-M-15 gene being dominant. SHV-type beta-lactamase genes, including newly identified alleles (SHV-201 and SHV-202) were detected at higher rate in (27%). Nine isolates of (3.9%) harbored carbapenemase genes; (phylogenetic group A-sequence type 2104 (A-ST2104), B2-ST73), (A-ST167, B2-ST38/ST2659-related STs), and (B1-ST101/ST224, D-ST6682). AmpC beta-lactamase genes ( and ) were detected in , which mostly harbored and plasmid-mediated quinolone resistance (PMQR) determinants (, , , , and ). A new CMY allele (CMY-160) belonging to CMY-2 group was identified in phylogenetic group D . Among , carbapenemase gene was detected in three isolates (2%); in ST11 and ST1322, and in ST43 isolate. As well as higher rate of in (39%), PMQR gene was also commonly found among isolates analyzed. These findings indicated spread of genes to diverse clones and emergence of in , with increased prevalence of ESBLs represented by CTX-M-15 in Bangladesh.