Antibiogram assay of pathogenic verotoxic E. coli isolated from poultry cloacal swabs

Abstract

The present study was conducted to isolate pathogenic Escherichia coli from cloacal swab of apparently healthy poultry and to determine their susceptibility to commonly used antibiotics. A total of 200 cloacal swab samples were collected aseptically and processed under required conditions for the isolation of E. coli. To confirm the isolates as E. coli, various biochemical tests like IMViC were performed. VTEC isolates were confirmed by using multiplex PCR. To assess the virulence of VTEC isolates, they were also subjected to Congo red dye assay. Antibiotic sensitivity pattern of pathogenic isolates was studied by Disc diffusion method. The percent positivity of E. coli was observed 80% (160/200) in cloacal swab samples. Based on multiplex PCR 23 isolates were found positive for VTEC. The percentage positivity on Congo red dye assay was 25.92%.The antibiogram of all 23 VTEC isolates against 15 antibiotics showed that majority of VTEC strains exhibited high level of sensitivity to Chloramphenicol, Imipenem and Amikacin. All isolates were 100% resistant to Clindamycin and Enrofloxacin.