Molecular characterization of diarrheagenic Escherichia coli isolated from meat products sold at Mansoura city, Egypt

Abstract

This study was carried out to determine the serological characteristics and virulence-associated genes of 32 Escherichia coli strains isolated from different meat products. Serotyping of somatic (O) and flagellar (H) antigens reveled that 3 strains were typed into 2 serogroups; O121:H19 (2 strains) and O148:H8 (1 strain), while the other 29 strains were not agglutinated with any serum. For molecular characterization, multiplex PCR has been performed by combining seven primer pairs specific for enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), and enteroinvasive E. coli (EIEC). The targets selected for each group were the genes encoding heat-labile (LT) and heat-stable (ST) toxins for ETEC isolates, eae, stx1 and stx2 for EHEC isolates, eae and bfpA for EPEC isolates, and ipaH for EIEC isolates. This facilitates simultaneous identification of the four different categories of diarrheagenic E. coli in a single reaction. Amongst the 32 E. coli strains tested, eleven (37.5%) were potentially diarrheagenic. Five of which (15.63%) were ETEC, three (9.38%) were EHEC, two (6.26%) were EPEC, and one strain (3.13%) was EIEC. The results appear to indicate that virulence gene-carrying E. coli strains are a normal part of intestinal bacterial populations that may be present among high numbers of E. coli contaminating meat products which do not necessarily correlate with disease.