Molecular and Serotyping Characterization of Shiga Toxogenic Escherichia coli Associated with Food Collected from Saudi Arabia

Abstract

Shiga toxin-producing Escherichia coli (STEC) strains are considered as one of the major food-borne disease agents in humans worldwide. STEC strains, also called verotoxin-producing E. coli strains. The objectives of this study were serotyping and   molecular characterization of shiga toxogenic E. coli associated with raw meat and milk samples collected from Riyadh, Saudi Arabia. A total of 540 milk samples were collected from 5 dairy farms and 150 raw meat samples were collected from different abattoirs located in Riyadh, Saudi Arabia. E. coli were recovered from 86 milk samples (15.93%), serotyping of the E. coli isolates revealed, 26 (4.81%) strains O157: H7, 23 (4.26%) strains O111, 20 (3.70%) strains O113: H21, 10 (1.85%) strains O22: H8 and 7 (1.3%) strains O172: H21. Meanwhile, 17 (11.33%) strains of E. coli were recovered from raw meat samples, serotyping of the E. coli isolates revealed, 6 (4%) strains O157: H7, 5 (3.33%) strains  O111 and 4 (2.67%) strains O174: H2 and only two (1.33%) strains were identified as O22: H8.  Stx1 gene was detected in 35 (33.98%) strains and stx2 was detected in 85 (82.52%) strains. Enterohemorrhagic E. coli (EHEC) types O157:H7, and only 8 (7.77%) strains of the STEC recovered from food were positive for the intimin eae gene, which is considered to be a marker gene for EHEC The results of this study revealed the efficiency of combination between serotyping and molecular typing of the E. coli isolates recovered from food of animal origin for rapid detection and characterization of STEC.

Keywords:  Foodborne, E. coli, Raw meat, Milk samples, Shiga toxin genes, intimin gene.