Publication:

Detection of extended spectrum β-lactamase among gram negative clinical isolates from a tertiary care hospital in South India

Background The β lactamase enzymes produced by the organisms break down the structural beta-lactam ring of β lactam antibiotics. Many genera of gram negative bacteria possess a naturally occurring, chromosomally mediated β lactamase and also some are plasmid mediated β lactamases. The objective of the study was to detect extended spectrum β lactamases among gram negative clinical isolates.

Methods 200 clinical were subjected to routine disc diffusion technique and zone diameter of ≤27mm for Cefotaxime and ≤22mm for Ceftazidime or ≤25mm for Ceftriaxone were included in this study. The strains are subjected to double disc synergy test.

Results Of 200 samples, 174 yielded organisms belonging to enterobacteriaceae and 26 yielded growth of nonfermenters. Out of 174 members of enterobacteriaceae family, 122 were E. coli, 36 Klebsiella spp, 8 Proteus spp, 5 Enterobacter spp and 3 Citrobacter spp. Out of 26 nonfermenters, 18 were Pseudomonas spp and 8 were Acinetobacter.

Conclusions In the present study prevalence of ESBL was 23.3%, the high prevalence may be due to irrational use of third generation cephalosporins in both the hospital and community.