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Transfer of verocytotoxigenic Escherichia coli O157, O26, O111, O103 and O145 from fleece to carcass during sheep slaughter in an Irish export abattoir

Thomas, K M, McCann, M S, Collery, M M, Moschonas, G, Whyte, P, McDowell, D.A. and Duffy, G. (2013) Transfer of verocytotoxigenic Escherichia coli O157, O26, O111, O103 and O145 from fleece to carcass during sheep slaughter in an Irish export abattoir. Food Microbiology, 34 (1). pp. 38-45. [Journal article]

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DOI: dx.doi.org/10.1016/j.fm.2012.11.014

Abstract

The purpose of this study was to investigate carriage and transfer of verocytotoxigenic Escherichia coli (VTEC) O157, O26, O111, O103 and O145 from fleece to dressed carcasses of 500 sheep, and to establish the virulence potential of recovered VTEC. Individual sheep were tracked and sampled (10 g fleece, full carcass swab) through the slaughter process. Samples were examined for the presence of verotoxin (vt1 and vt2) genes using a duplex real-time PCR assay and positive samples were further screened for the presence of the above five serogroups by real-time PCR. VTEC cells were recovered from PCR positive samples by serogroup specific immunomagnetic separation and confirmed by serogroup specific latex agglutination and PCR. Isolates were subject to a virulence screen (vt1, vt2, eaeA and hlyA) by PCR and isolates carrying vt genes were examined by Pulsed-Field Gel Electrophoresis (PFGE). VTEC O26 was recovered from 5/500 (1.0%) fleece and 2/500 (0.4%) carcass samples. VTEC O157was isolated from 4/500 (0.8%) fleece samples and 3/500 (0.6%) carcass samples. E. coli O103 was recovered from 84/500 (16.8%) fleece and 68/500 (13.6%) carcasses, but only one E. coli O103 isolate (0.2%) carried vt genes. E. coli O145 was recovered from one fleece sample, but did not carry vt genes. E. coli O111 was not detected in any samples. For the four serogroups recovered, the direct transfer from fleece to carcass was not observed with PFGE showing that VTEC O26 isolates from a matched fleece/carcass “pair” were not identical. This study shows that while VTEC O157 are being carried by sheep presented for slaughter in Ireland, other potentially clinically significant verotoxin producing strains (particularly VTEC O26) are emerging.

Item Type:Journal article
Keywords:Verocytotoxigenic, Escherichia coli, Sheep, Abattoir, Fleece, Carcass
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Health Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
ID Code:24967
Deposited By: Professor David McDowell
Deposited On:15 Feb 2013 14:45
Last Modified:10 May 2017 11:28

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