Isolation and Molecular Characterization of Non-Sorbitol Fermenting Escherichia coli Isolated From Fresh Ground Beef

Abstract

Background: Escherichia coli O157:H7 (EHEC) has been traditionally associated with foodborne infections from consumption of foods with animal origin such as ground beef and burgers. Objectives: The objective of this study was to investigate the contamination of fresh ground beef with non-sorbitol fermenting Escherichia coli and presence of virulence genes in isolates obtained from butchers located in Ahvaz, Iran. Materials and Methods: A total of 200 fresh ground beef were sampled during a six-month period. All samples were enriched in Tryptic Soy Broth (TSB) with novobiocin and plating on Cefixime Telluride-Sorbitol MacConkey (CT-SMAC). The suspected colonies were subjected to Polymerase Chain Reaction (PCR) analysis to identify virulence genes containing rfbE O157, flic H7, stx1 and stx2 genes. Results: Overall, 1.5% of ground beef samples were contaminated with the O157 E. coli strain meanwhile 1% of samples contained the O157:H7 strain and 0.5% of samples had the O157:H7 with virulent stx1 and stx2 genes. Conclusions: The observed results indicated the necessity of good care in abattoir, butcheries and during food distribution, mainly ground beef. Also, a zero tolerance policy could be useful to control E. coli O157 in meat products nationwide.