Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada
Citation
Essendoubi, S., Yang, X., King, R., Keenliside, J., Bahamon, J., Diegel, J., Lu, P., Cassis, R., Gensler, G., Stashko, N., Rolheiser, D. 83(11), 1909-1917. http://dx.doi.org/10.4315/JFP-20-146
Plain language summary
This study was carried out to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada, in response to the outbreaks associated with pork produced in Alberta in the last few year. In total, 504 samples were collected from carcasses and colon of healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were genetically related. Six E. coli O157:H7 isolates obtained over 8 month period from one PLA that only processed hogs and sourced hogs from one farm were of indistinguishable genoypes. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype. This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms. This information is important to the hog producers to implement control measures to reduce E. coli O157 originating from healthy pigs.
Abstract
Copyright ©, International Association for Food Protection. ABSTRACT: The objective of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for E. coli and aerobic colony count (ACC). Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. These positives were found in 5 (12.8%) of 39 PLAs from hogs originating from eight farms. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were clonal, as determined by pulsed-field gel electrophoresis. Six E. coli O157:H7 isolates obtained over 8 months from one PLA that only processed hogs and sourced hogs from one farm had indistinguishable pulsed-field gel electrophoresis patterns. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype, suggesting that swine can carry E. coli O157:H7 of importance to human health. All carcass sponge swabs (100%) were positive for ACC. E. coli was present in 72% of carcass swabs. Carcasses from PLAs slaughtering both beef and hogs had a numerically higher ACC mean value but not statistically different compared with the carcasses from PLAs slaughtering only swine (2,799 and 610 CFU/cm2, respectively). E. coli showed a similar trend with a mean value of 0.88 CFU/cm2 in PLAs slaughtering both species and 0.26 CFU/cm2 in PLAs slaughtering only swine (P ≤ 0.05). This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms.