Routine Screening For ESBL Production, A Necessity Of Today

Background: Extended spectrum beta lactamases (ESBL) are plasmid mediated enzymes capable of hydrolyzing broad spectrum cephalosporins and monobactams. ESBL producing organisms also show cross resistance to many other antibiotics, limiting therapeutic options. Aim: To study the frequency of ESBL producers among Enterobacteriaciae, their prevalence in the hospital and their susceptibility pattern to other antibiotics. Materials And Methods: Between July 2004 to Dec. 2004, a total of 1889 clinically significant Gram negative bacilli belonging to Enterobacteriaciae isolated from various clinical specimens were subjected to screening for ESBL production by standard techniques. Results: ESBL production was noted in 60.98% (n=1152/1889) of the isolates tested. Percentage of ESBL producers within a species was highest in Enterobacter species 70.9% (n=105/148) followed by Klebsiella species 67.4% (n=439/651) and E.coli 62.34% (n= 568/911). The most frequent ESBL producer was E.coli from ambulatory and ward samples, while from intensive care units it was Klebsiella species. Sensitivity of these isolates to Meropenem was 99.8%, piperacillin tazobactam 96.8%, cefoperazone sulbactam 93.3%. Conclusion: There is a high prevalence rate of ESBL producers among Enterobacteriaciae. E.coli and Klebsiella species pose a major concern among these. Routine detection of ESBL production in clinical laboratories gives valuable information to the clinician in appropriate selection of antibiotics.