Antibiotic Resistance in Diarrheagenic Escherichia coli Isolated from Broiler Chickens in Pakistan

Background: Diarrheagenic Escherichia coli (DEC) strains are predominant cause of gastrointestinal tract illnesses. The main objective of the study was to determine antibiotic resistance in various types of DEC isolated from chicken broilers farmed in Pakistan. Methods: A total of 200 feces and 200 meat samples from broiler chickens were collected from the slaughtering shops in Southern Punjab, Pakistan. The confirmed fecal (n=150) and meat (n=150) E. coli isolates were investigated against 16 antibiotics. Fourteen virulence genes specific for Enteropathogenic (EPEC), Shiga Toxin-producing (STEC), Enteroinvasive (EIEC), Enteroaggregative (EAEC), and Enterotoxigenic (ETEC) E. coli were identified using Polymerase Chain Reaction. Results: EPEC was the most detected pathotype in both feces (76%) and meat (90%) samples, followed by STEC, EIEC, and ETEC. The highest resistance (40-90%) was observed against penicillin, oxytetracycline, and nalidixic acid in fecal isolates. More than 50% EPEC and EAEC fecal isolates, and 60% EAEC meat isolates were simultaneously resistant to 6 or more antibiotics. Conclusion: Conclusively, the broiler meat sold in open markets of Pakistan was considerably contaminated with multi-drug resistant DEC. To mitigate the issue, the gov- ernment should regulate the use of antibiotics at poultry farms and monitor slaughtering practices in slaughterer houses.