title: Prevalence, risk factors and genetic diversity of methicillin-resistant Staphylococcus aureus carried by humans and animals across livestock production sectors.
abstract: OBJECTIVE
  This study aimed to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in animals and humans on veal, dairy, beef and broiler farms and to compare the risk for human MRSA carriage with that of strictly horticulture farmers. The genetic background, resistance phenotypes and genotypes and toxin gene content of the isolated MRSA strains were compared with MRSA collected on MRSA clonal complex (CC)398-positive pig farms.
  
  
  METHODS
  MRSA carriage isolates were genotyped (spa, SCCmec and multilocus sequence typing), resistance to 16 antimicrobials was determined and resistance and toxin genes were detected.
  
  
  RESULTS
  MRSA carriage rates were higher (P<0.01) on veal farms (calves, 64%; farmers, 72%) compared with on dairy (cows, 1%), beef (cows, 5%; farmers, 11%), broiler (pooled broths, 5%; farmers, 3%) and horticulture (farmers, 3%) farms. The intensity of animal contact was identified as a risk factor for human MRSA carriage. The vast majority of MRSA (n=344), including those from pigs, were CC398 (98%). SCCmec V(5C2), V(5C2&5)c, IV(2B) and IV(2B&5) predominated. MRSA CC130 and CC599 carrying mecC were detected in beef and dairy cattle. MRSA from veal calves were significantly more resistant than MRSA from pigs (P<0.01). A few isolates, including mecC-carrying MRSA, harboured pyrogenic superantigen toxins. Human- and animal-derived MRSA from individual farms showed similar characteristics.
  
  
  CONCLUSIONS
  This systematic cross-sector survey revealed a high prevalence of multiresistant livestock-associated MRSA on Belgian veal calf farms as compared with other farm types. MRSA harbouring mecC was detected at a low frequency in beef and dairy cows, but not in humans.
authors: Laboratoire de Référence MRSA-Staphylocoques, Department of Microbiology, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium. stien.vandendriessche@gmail.com
authors: Stien
authors: S
authors: Vandendriessche
authors: Wannes
authors: W
authors: Vanderhaeghen
authors: Filomena Valente
authors: FV
authors: Soares
authors: Marie
authors: M
authors: Hallin
authors: Boudewijn
authors: B
authors: Catry
authors: Katleen
authors: K
authors: Hermans
authors: Patrick
authors: P
authors: Butaye
authors: Freddy
authors: F
authors: Haesebrouck
authors: Marc J
authors: MJ
authors: Struelens
authors: Olivier
authors: O
authors: Denis
mesh_terms: D000818:Animals; D001530:Belgium / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology / Q000662:veterinary*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D058751:Livestock; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000662:veterinary*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D037521:Virulence Factors
keywords: MRSA; S. aureus; antimicrobial resistance epidemiology; food animals; molecular epidemiology; public health