Prevalence of extended spectrum β-lactamase, AmpC β-lactamase and metallo β-lactamase mediated resistance in Escherichia coli from diagnostic and tertiary healthcare centers in south Bangalore, India

Background: The increasing reports on multidrug resistant Escherichia coli has become a potential threat to global health. Here, we present a cross-sectional study to characterize extended spectrum β-lactamase, AmpC β-lactamase and metallo β-lactamase producing E. coli isolated from different human clinical samples.Methods: A total of 300 clinical Gram negative bacterial isolates were collected and re-characterized for the identification of E. coli following standard microbiological techniques. The antimicrobial susceptibility of E. coli isolates was initially screened by Kirby-Bauer disk diffusion and MIC methods. The resistant isolates were confirmed to be ESBL, AmpC and MBL producers by their respective phenotypic confirmatory tests of combined disc method.Results: We identified 203 (68%) E. coli and 97 (32%) Non-E. coli isolates. The highest recovery of E. coli was from urine samples 72 (35%). Combined disc method using ceftazidime/ceftazidime+clavulanic acid and cefotaxime/cefotaxime+clavulanic acid confirmed 156 (79%) and 144 (73%) E. coli as ESBL producers, respectively. Thirty-four (34%) and 16 (27%) resistant E. coli isolates were confirmed to be AmpC and MBL producers, likewise.Conclusions: Increased prevalence of ESBL, AmpC and MBL producing E. coli were observed. Beta-lactamase mediated resistance appears to be prime mechanism in the multidrug resistant E. coli. Thus, early detection of beta lactamase producing E. coli is necessary to avoid treatment failure and prevent the spread of MDR