Extended Spectrum Beta Lactamases Detection Using Two Phenotypic Methods Among Uropathogenic Escherichia Coli.

Abstract

Background:Extended spectrum β-lactamase(ESBL) is an important mechanism of beta-lactam resistance among Gram negative bacteria. The ESBL detection method as described by Clinical Laboratory Standards Institute(CLSI) is used routinely. This method however is not able to detect ESBL in presence of AmpC which is another important mechanism of drug resistance among these bacteria. This study was thus undertaken to compare CLSI recommended method with Cefepime-clavulanic acid method. Materials and Methods:A total of 216 non repetitive (Escherichia coli) E.coli isolates from urine samples were screened for resistance to Cefpodoxime and Cefotaxime.Those with screening test positive isolates were confirmed for ESBL production using the two phenotypic detection methods. Results:Among total 216E.coli isolates only 128(59%) were potential ESBL producers. Of these 109 were positive by using CLSI recommended method while 112 by using Cefepime-clavulanic acid method.Conclusion:Use of Cefepime-clavulanic acid increases sensitivity for ESBL detection in presence of AmpC.