Surveillance for enterotoxigenic & enteropathogenic Escherichia coli isolates from animal source foods in Northwest Iran

ABSTRACT

Background & objectives: Diarrhoeagenic Escherichia coli strains are common agents of diarrhoea particularly in developing countries. Food products of animal origin are considered as common carriers of E. coli. This study was undertaken to identify enterotoxigenic Escherichia coli (ETEC) and enteropathogenic E. coli (EPEC) pathotypes in animal-source foods (ASF). Methods: A total of 222 ASF samples were investigated. Based on the culture and biochemical tests, 109 E. coli isolates were identified. Duplex-polymerase chain reaction assay was used to detect ETEC and EPEC. The target genes selected for each category were the lt and st for the ETEC, and eae and bfp for the EPEC isolates. Results: The occurrence of E. coli in dairy and meat products was 45 and 52.5 per cent, respectively. Among the E. coli isolates, two ETEC, one typical EPEC and three atypical EPEC were detected in meat samples, whereas only one typical EPEC and one atypical EPEC were detected in dairy samples. Interpretation & conclusions: Our results showed presence of ETEC and EPEC strains in ASFs. The milk without pasteurization and traditional dairy products produced in unhygienic conditions are most likely the main sources of E. coli pathotypes and other zoonotic pathogens and thus can be considered a potential hazard to the health of the community.