Prevalence of CTX-M β lactamases among Gram negative bacteria in a tertiary care hospital in Bangladesh

Abstract

Extended spectrum beta lactamases (ESBLs) produced by Gram negative bacteria are mainly mediated by three important genes, namely TEM, SHV and CTX-M. In this study, we used a multiplex PCR to determine the prevalence of CTX-M and its subgroups CTX-M-3, CTX-M-14, among the members of Enterobacteriaceae family and in Pseudomonas spp that were isolated from different clinical samples in a tertiary care hospital in Bangladesh. A total of 300 culture positive clinical isolates were selected for the study. Out of these, 216 from urine, 45 from wound swab, 39 from pus aspirates. The ESBL status was determined by double disc diffusion test (DDDT) as recommended by Clinical Laboratory Standard Institute 2010 (CLSI) and by multiplex PCR for TEM, SHV and CTX-M, CTX-M-3, CTX-M-14 genes. Out of 300 isolates tested, 71.3% were positive for ESBL production by DDDT. The rate of positivity for TEM, SHV and CTX-M genes in 107 randomely selected isolates was 83.2%. Among these, 56.2% (50/89) was positive for CTX-M. Among the CTX-M positive isolates, CTX-M-3 and CTX-M-14 were 78.0% (39/50) and 80.0% (40/50) respectively. Our study demonstrated that CTX-M variants were common in Enterobacteriaceae and Pseudomonas spp prevalent in the hospital of Bangladesh. Ibrahim Med. Coll. J. 2015; 9(1): 26-30