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NJBMS - Volume 1, Issue 3, January - March 2011

Pages: 142-145
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Author: R.Indra Priyadharsini, K. R. Rajesh, S. Mathavi, Reena Rajan, K. S. Seetha

Category: Microbiology


Background :

Antimicrobial resistance is an emerging problem in health care settings. One of the common mechanisms of antimicrobial resistance is production of Extended- Spectrum Beta-Lactamase (ESBL) by Gram Negative Bacilli. Knowledge about the prevalence of ESBL producing strains in the local area must be obtained for proper therapeutic interventions in infections caused by them.

Aims and Objectives :

The purpose of the study was to detect the prevalence of Extended-Spectrum Beta-Lactamase producing Enterobacteriaceae isolates from various infections in a Tertiary Care Hospital, which guides in therapeutic management of such infections.

Materials andMethods :

A total of 2456 various clinical samples from hospitalized patients were recovered over a period of five months (Nov.2009 to March 2010). Clinical specimens were cultured and isolates were identified by conventional biochemical reactions. A total of 778 isolates were obtained, out of which 480 isolates were Enterobacteriaceae. The isolates were subjected to antimicrobial susceptibility test by standard methods. The Enterobacteriaceae isolates with reduced susceptibility to any of the third generation

Cephalosporins (3GC) were selected for further study. Phenotypic detection of ESBL production was done by Double Disc Synergy Test and confirmed by MIC by agar dilutionmethod.


In our study, among the 480 i s o l ates of Enterobacteriaceae, 91 (18.95 %) were positive for ESBL by Double Disc Synergy Test (DDST) and confirmed by Minimum Inhibitory Concentration (MIC). Among the 91 ESBL producing isolates, 65 (26.42 %) were Escherichia coli and 26 (16.6 %) were Klebsiella spp. Eighty two isolates (90.10%)showed multidrug resistance.


The ESBL production is associated with resistance to other antibiotics in our study. Prudent use of antibiotics and continuous surveillance programmes are mandatory to curb the dissemination of multidrug resistant strains in the hospital set up.

Keywords: ESBL, Enterobacteriaceae, Hospitalizedpatients.