Detection of Extended Spectrum β-lactamases Producing Genes among Third Generation Cephalosporins Sensitive Bacterial Strains from a Medical College Hospital in Bangladesh

Abstract

Background: Extended Spectrum β-lactamases (ESBLs) are rapidly evolving group of β-lactamase enzymes produced by the gram-negative bacteria which is very important to detect in clinical laboratory for effective treatment. The aim of the present study was to see the ESBL genes among Third Generation Cephalosporins (3GCs) sensitive bacterial strains. Methods: This cross sectional study was undertaken in non-repetitive clinical isolates collected from Mymnesingh Medical College Hospital, Mymensingh, Bangladesh from both the outpatient and inpatient departments over a period of six months from January 2011 to June 2011. The ESBL status was confrmed by double discdiffusion test and minimum inhibitory concentration by agar dilution method as recommended by Clinical and Laboratory Standard Institute 2010 and multiplex polymerase chain reaction for TEM, SHV and CTX-M genes. Results: A total of 300 Gram negative bacilli were included in the study; among them 236 were resistant and 64 were sensitive to 3GCs by disc diffusion test. Multidrug resistant ESBL production was found 75.8% from resistant isolates and 54.6% from sensitive isolates. Rate of TEM, SHV and CTX-M genes present among sensitive strains were 36.4%, 24.2% and 21.1%, respectively. Conclusion: Both common and new ESBLs genes were detected from 3GCs sensitive bacteria of which TEM is most common. Routine ESBLs screening for all Gram-negative isolates both from sensitive and resistant to 3GCs strains might be useful for the physicians in selecting effective antibiotics.