title: Prevalence of methicillin-resistant Staphylococcus aureus in Canadian commercial pork processing plants.
abstract: OBJECTIVE
  This study investigated the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA), their spa-types, and antimicrobial resistance profiles at various steps during commercial pork production from three plants designated as A, B and C.
  
  
  RESULTS
  Over a period of 1 year 2640 samples from three commercial pork plants were obtained on a rotating basis. Sample sources were: nasal swabs after bleeding (NSAB), nasal swab after scalding (NSASs, plant C) or skinning (NSASk, plants A, B), carcass swabs after pasteurization (CSAP, plant C) or washing (CSAW, plants A, B) and retail pork (RP). Overall MRSA prevalence at each sampling point in the pork plants after adjusting for clustering was: 61·93, 28·38 7·58 and 1·21% for NSAB, NSASc/Sk, CSAP/CSAW and RP respectively. The majority of MRSA isolates from the three pork plants belonged to livestock-associated MRSA spa-types t034 and t011 (3·8%; ST398). The mainly human spa-type t002 (15%) was also recovered. All MRSA isolates were resistant to β-lactam and tetracycline antibiotics. Overall resistance to tigecycline was found in about 10% of MRSA isolates while <3% isolates were resistant to daptomycin, gentamicin, quinupristin/dalfopristin and trimethoprim/sulfamethoxazole.
  
  
  CONCLUSIONS
  A higher prevalence of MRSA in the nasal cavity of incoming pigs was observed at all three plants, but a notable reduction in MRSA along the pork processing steps occurred.
  
  
  CONCLUSIONS
  The highest prevalence of MRSA was found in the nasal cavity of incoming pigs in three commercial pig slaughter and pork processing plants. A reduction in MRSA prevalence occurred along the processing chain, and pork products from these plants showed significantly lower MRSA than the initial steps of slaughter and processing, suggesting a reduction in MRSA during the slaughter process with minimal cross-contamination.
authors.affiliation: Department of Food Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Narvaez-Bravo
authors.affiliation: Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, AB, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Toufeer
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON, Canada.
authors.forename: S J
authors.initials: SJ
authors.lastname: Weese
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada.
authors.forename: M S
authors.initials: MS
authors.lastname: Diarra
authors.affiliation: Public Health Agency of Canada, Guelph, ON, Canada.
authors.forename: A E
authors.initials: AE
authors.lastname: Deckert
authors.affiliation: Public Health Agency of Canada, Guelph, ON, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Reid-Smith
authors.affiliation: Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, AB, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Aslam
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002170:Canada; D003257:Consumer Product Safety; D005506:Food Contamination / Q000706:statistics & numerical data; D005511:Food Handling / Q000295:instrumentation; D006801:Humans; D008460:Meat / Q000191:economics / Q000382:microbiology*; D008712:Methicillin / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D015995:Prevalence; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D008712:Methicillin
keywords: antimicrobial resistance; methicillin-resistant Staphylococcus aureus; pork processing plant; retail pork; spa-typing