From Farm to Table: Follow-Up of Shiga Toxin-Producing Escherichia coli Throughout the Pork Production Chain in Argentina

RUIZ, M.J.; PADOLA, N.L.; COLELLO, R.; SANZ, M.; CACERES, M.E.; ETCHEVERRÍA, A.I.

fRONTIERS IN MICROBIOLOGY

New York, Springer International.

Año: 2016 vol. 7 p. 1 - 7

1664-302X

Pigs are important reservoirs of Shiga toxin-producing Escherichia coli (STEC). The entrance of these strains into the food chain implies a risk to consumers because of the severity of hemolytic uremic syndrome. This study reports the prevalence of Shiga toxin-producing Escherichia coli (STEC) throughout the pork production chain and the characterization of the isolates. From 764 samples, 31 (4.05%) were stx positive by PCR screening. At farms from rectal swabs from different animals at production stages we found 2.86% of STEC prevalence; in carcasses we detected 4.08% and 6% of STEC at the slaughter and boning rooms, respectively. These percentages decreased in pork meat ready for sale at sales markets (4.59%). From positive samples, 50 isolates could be characterized. In farms 37.5% of the isolates carried stx1/stx2 genes, 37.5% possessed stx2e and 25% carried stx2 only. At slaughter we detected 50% of isolates positive for stx2, 33% for stx2e and 16% for stx1/stx2. At boning rooms 59% of the isolates carried stx1/stx2 genes, 14% stx2e and 5% stx1/stx2/stx2e. At retail markets we detected 66% of isolates positive for stx2, 17% stx2e and 17% stx1/stx2. For the other virulence factors, ehxA and saa were not detected and eae gene was detected in 12% of the isolates. Putatives adhesins were also detected, where agn43 was found in 72% of isolates, ehaA in 26%, aida in 8% and iha in 6%. The strains were typed into 14 E. coli O groups (O1, O2, O8, O15, O20, O35, O69, O78, O91, O121, O138, O142, O157, O180) and ten H groups (H9, H10, H16, H21, H26, H29, H30, H32, H45, H46). These results highlight the need to implement an integrated STEC control system based on good management practices on the farm and critical control point systems in the food chain.