Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada.

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.

Antimicrobial resistance of bovine Salmonella enterica ssp. enterica isolates from the Alberta Agriculture and Forestry Disease Investigation Program (2006-2014).

The objectives of this study were to describe the antimicrobial susceptibility and serotypes of clinical Salmonella spp. isolates from Alberta cattle, to inform antimicrobial stewardship decisions for Alberta bovine veterinarians and to provide data for national surveillance. Isolates were collected from cattle and serotyped by Alberta Agriculture and Forestry from 2006 to 2014. Susceptibility testing was completed using Canadian surveillance breakpoints. There were 81 unique Salmonella isolates from 72 visits to 27 farms. The majority of isolates were S. Typhimurium (66.7%) and S. Dublin (19.8%). The prevalence of multidrug resistance was high in S. Typhimurium (89.1%) and S. Dublin (93.8%), including ceftiofur resistance (43.6% and 68.8%, respectively), while there was no resistance in other serotypes. As ceftiofur is a recommended treatment option for enteritis and septicemia caused by Salmonella in cattle, these results reinforce that obtaining bacterial culture and susceptibility results is critical for suspected cases of bovine salmonellosis in Alberta.

Antibiorésistance des isolats bovins de Salmonella enterica ssp. enterica provenant du Programme d'enquête du ministère de l'Agriculture et des Forêts de l'Alberta (2006­2014). Les objectifs de cette étude consistaient à décrire la susceptibilité antimicrobienne et les sérotypes des isolats cliniques de Salmonella spp. provenant du bétail de l'Alberta afin de fournir des données nationales de surveillance et d'informer les décisions d'antibiogouvernance des vétérinaires bovins de l'Alberta. Les isolats ont été prélevés du bétail et sérotypés par le ministère de l'Agriculture et des Forêts de l'Alberta de 2006 à 2014. Les tests de susceptibilité ont été réalisés en utilisant des points de référence de la surveillance canadienne. Il y avait 81 isolats uniques de Salmonella provenant de 72 visites à 27 fermes. La majorité des isolats étaient S. Typhimurium (66,7 %) et S. Dublin (19,8 %). La prévalence de la multirésistance aux médicaments était élevée pour S. Typhimurium (89,1 %) et S. Dublin (93,8 %), y compris la résistance au ceftiofur (43,6 % et 68,8 %, respectivement), tandis qu'il n'y avait pas de résistance pour d'autres sérotypes. Vu que le ceftiofur est une option de traitement recommandée pour l'entérite et la septicémie causées par Salmonella chez le bétail, ces résultats servent de renforcement pour confirmer qu'il est crucial d'obtenir des cultures bactériennes et des résultats de susceptibilité pour les cas suspectés de salmonellose bovine en Alberta.(Traduit par Isabelle Vallières).

Prevalence of Salmonella spp. in environmental samples from table egg barns in Alberta.

Some Salmonella spp. are zoonotic, a frequent cause of foodborne illness in Canada, and known to infect humans through contaminated poultry and poultry products. Certain serotypes of Salmonella spp. have been demonstrated to be vertically transmitted from hen to egg. The incidence of Salmonella spp. isolation in the flock has been correlated to its isolation from the environment. Twenty-one producers were enrolled in this study to examine the occurrence of Salmonella spp. in 48 table egg layer flocks housed in 35 barns in Alberta. The purpose of this study was to: (i) identify Salmonella serotypes isolated from the environment of table egg layer facilities in Alberta and (ii) record the prevalence of Salmonella spp. across eight defined environmental sampling points. Salmonella spp. were isolated from the environment of 20/35 barns representing 29/48 flocks. The most common serotypes isolated were S. Heidelberg, S. Kentucky and S. Mbandaka. The order of most to least contaminated sample location was manure belts (54.1%), feeders (47.9%), feed motors (45.8%), egg belts and walls (41.7%), fans (35.0%), cage bottoms (31.3%) and lobbies (27.1%). Salmonella spp. were isolated from 7/7 barns post cleaning and disinfection, demonstrating the persistence of this organism in the environment and the need for effective eradication protocols.

Antimicrobial resistance of Salmonella enterica serovar Heidelberg isolated from poultry in Alberta.

Salmonella enterica serovar Heidelberg is one of the top three serovars implicated in human infections in Canada. In 2003, the Canadian Integrated Program for Antimicrobial Resistance Surveillance reported antimicrobial resistance (AMR) in S. Heidelberg in Canada. The study objective was to investigate the AMR of S. Heidelberg isolated from poultry in Alberta. We examined 951 S. Heidelberg poultry isolates obtained during 1996 to 2010 and tested against 18 antibiotics using the Sensititre AVIAN1F system. Temporal resistance patterns were analysed using single-level logistic regression models. Continuous variables were included in the multivariable models. Multivariable models were built and variables and interactions were included in these final models. Data were analysed using Stata 11 Intercooled. Ceftiofur resistance ranged annually from 0 to 10.5% and gentamicin resistance ranged annually from 0 to 33.3%; no isolates were enrofloxacin resistant. Resistance to amoxicillin (annual range 0 to 42.6%) varied significantly by time and interaction with commodity type. Meat turkey S. Heidelberg isolates had higher ceftiofur resistance compared with chickens: layers plus layer breeders (odds ratio = 22.6, P < 0.01) and broiler breeders (odds ratio = 9.1, P < 0.01). Gentamicin resistance decreased significantly over the study period (odds ratio = 0.72 per year, P < 0.01). Tetracycline (TET) resistance changed significantly over time (annual range 0 to 39.6%), interacting with poultry commodity type. Meat turkey isolate TET resistance, higher overall than that of chicken, increased throughout the study. All turkey breeder isolates were resistant to TET. In conclusion, this study provides AMR data for S. Heidelberg isolates from the Alberta poultry industry and demonstrated significant trends in resistance, both temporal and between poultry commodities.