Determination of Carbapenem and Extended Spectrum Beta Lactamases in E. Coli from Commercial Broilers, Sri Lanka

Association between antimicrobial resistance in human and livestock have been widely discussed. The same or closely associated sequence type of E. coli has been reported in poultry and causing clinical infection in humans. The objective of this study was to determine phenotypic and genotypic antimicrobial resistance among E coli isolated from commercial broiler integrators (n=6) in the country. Ceacal samples (n=521) were collected from commercial broiler processing plants and E.coli was isolated and identified by conventional bacteriological methods followed by selected biochemical tests. Antimicrobial susceptibility testing and interpretation were done by disk diffusion tests as described in EUCAST. The conventional PCR tests were carried out for CTX-M for ESBL phenotypically resistant isolates and NDM for meropenem resistance isolates. NDM and CTX-M were found in 0.38% and 18.2 % in E. coli respectively. High frequency of phenotypic resistance was observed against neomycin (100%), tetracycline (99%), ampicillin/amoxycillin (98%), and quinolone (91.5%), gentamicin (79%), and over 50% of the frequency of antimicrobial resistance were shown against amoxycillin + Clavulanic acid, streptomycin and chloramphenicol. All these classes of antimicrobial are widely used in commercial broiler operations in the country. NDM has not been reported in E. coli from commercial poultry previously, although NDM had been reported in human clinical isolates. Prudent usage of antimicrobials, strengthening resistance surveillance, molecular epidemiological studies, and understanding the role of the mobile genetic elements are strongly recommended to minimize the risk of dissemination of antimicrobial resistance in humans.