title: Characterization of methicillin-resistant non-Staphylococcus aureus staphylococci carriage isolates from different bovine populations.
abstract: OBJECTIVE
  This study aimed at investigating bovine non-Staphylococcus aureus staphylococci for their role as a potential reservoir for methicillin resistance.
  
  
  METHODS
  Nasal swab samples were collected from 150 veal calves on 15 veal farms, 100 dairy cows on 10 dairy farms and 100 beef cows on 10 beef farms. Suspected staphylococcal isolates were investigated by PCR for the presence of the classic mecA and mecA(LGA251). Methicillin-resistant non-S. aureus staphylococci (MRNAS) were genotypically identified and were characterized by broth microdilution antimicrobial susceptibility testing and staphylococcal cassette chromosome mec (SCCmec) typing.
  
  
  RESULTS
  The MRNAS (n = 101) carriage rate was estimated as 30.29% (95% CI 6.14%-74.28%) in veal calves, 13.1% (95% CI 1.28%-63.72%) in dairy cows and 24.8% (95% CI 11.97%-44.42%) in beef cows. Carriage rates were not significantly different between the three populations (P > 0.05). mecA(LGA251) was not detected. Most (n = 80) MRNAS were identified as Staphylococcus sciuri, Staphylococcus lentus or Staphylococcus fleurettii. Resistance to aminoglycosides, macrolide-lincosamide-streptogramin antimicrobials, tetracycline and ciprofloxacin was frequently detected. Two linezolid-resistant MRNAS from veal calves carried the multidrug-resistance gene cfr. SCCmec cassettes of type III predominated (n = 46); another 40 SCCmec cassettes harboured a class A mec complex without identifiable ccr complex; type IVa, type V and several other non-typeable cassettes were detected in low frequencies, especially in methicillin-resistant Staphylococcus epidermidis.
  
  
  CONCLUSIONS
  The SCCmec types predominating in bovine MRNAS differ from those mostly detected in livestock-associated methicillin-resistant S. aureus strains. Yet, the detection of cfr and the high level of other antimicrobial resistances suggest a potentially important role of bovine MRNAS as a reservoir for resistance determinants other than SCCmec.
authors.affiliation: Operational Directorate Bacterial Diseases, Veterinary and Agrochemical Research Centre, Groeselenbergstraat 99, B-1180 Ukkel, Belgium. Wannes.Vanderhaeghen@coda-cerva.be
authors.forename: Wannes
authors.initials: W
authors.lastname: Vanderhaeghen
authors.forename: Stien
authors.initials: S
authors.lastname: Vandendriessche
authors.forename: Florence
authors.initials: F
authors.lastname: Crombé
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Nemeghaire
authors.forename: Marc
authors.initials: M
authors.lastname: Dispas
authors.forename: Olivier
authors.initials: O
authors.lastname: Denis
authors.forename: Katleen
authors.initials: K
authors.lastname: Hermans
authors.forename: Freddy
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: Patrick
authors.initials: P
authors.lastname: Butaye
mesh_terms: D000818:Animals; D002353:Carrier State / Q000382:microbiology / Q000662:veterinary*; D002417:Cattle; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D009297:Nasal Mucosa / Q000382:microbiology; D058974:Phylogeography; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013210:Staphylococcus / Q000187:drug effects* / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial