OCCURRENCE, VIRULENCE GENES AND ANTIMICROBIAL RESISTANCE OF ESCHERICHIA COLI O157 IN BOVINE, CAPRINE, OVINE AND PORCINE CARCASSES IN GREECE

Abstract

ABSTRACTOne thousand and two hundred carcasses (620 bovine, 130 caprine, 230 ovine and 220 porcine) from several slaughterhouses throughout Greece were examined for the presence of Escherichia coli O157 after evisceration and before chilling. Twelve E. coli O157 strains (1.0%) were isolated of which eight were from bovine (1.3%), one from caprine (0.8%) and three from ovine (1.3%) meat. None was isolated from pork meat. Six out of the 12 E. coli O157 isolates (50.0%) could be classified as Shiga‐toxigenic based on polymerase chain reaction (PCR), belonged to the E. coli O157:H7 serotype and were PCR‐positive for the stx1, stx2 and eae genes except one isolate that was stx1‐negative. The remaining six E. coli O157 isolates tested negative for Shiga‐toxin production, both by immunoassay and by PCR, were PCR‐negative for the eae gene, and all except one (strain LFH34, a bovine carcass isolate) were also PCR‐negative for the H7 flagellar gene. Among the 15 antimicrobials tested, the E. coli O157 isolates were the most frequently resistant to ticarcillin (9 out of the 12 isolates, 75%).PRACTICAL APPLICATIONSThe Shiga toxin‐producing Escherichia coli (STEC) strains are severe human pathogens. Although the prevalence of STEC in bovine meat has been investigated in several countries worldwide, no such study has been conducted previously in Greece. In addition, very few studies in the literature have reported on the prevalence and characterization of STEC isolated from animal carcasses other than bovine. The findings of the present study are also useful for epidemiological purposes (monitoring the evolution and spread of STEC worldwide).