Phenotypic detection of ESBL and Amp C beta lactamase among clinical isolates of Enterobacteriaceae

Abstract

Emergence of ESBL & amp C β-Lactamase enzymes among clinical isolates of poses a significant public health concern. Antimicrobial agents like 3 generation cephalosporins, clavulanic acid, imipenem etc. can induce amp C enzyme production. Sometimes the automated antimicrobial susceptibility testing systems fails to detect Amp C phenotype due to presence of multiple resistance mechanisms in gram negative bacilli. To overcome such difficulty, the study was undertaken to detect the presence ESBL and Amp C enzymes among clinical isolates of by phenotypic methods. strains isolated from various clinical samples were included in the study. Strains resistant to two or three groups of antibiotics (MDR) were further tested for the presence of ESBL enzyme by combination disk method. Amp C enzymes were detected by cefoxitin- cloxacillin disc method.A total1059 strains were isolated from various clinical samples. Out of these, 170 MDR strains were further processed. ESBL enzymes were detected in 104 (61%) strains and Amp C in 35 (20.5%) strains. 26(15.2%) strains were co-producers. Detection of ESBL and Amp C enzymes will help clinician in choosing the right antimicrobial treatment for the patient. Routine reporting of presence of Amp C & ESBL enzymes by phenotypic methods can be easily implemented by clinical microbiology laboratory. Cefoxitin-cloxacillin disk test is simple & rapid method for detection of Amp C β- lactamase enzyme.