title: Occurrence and characterization of methicillin-resistant staphylococci from bovine mastitis milk samples in Finland.
abstract: BACKGROUND
  Methicillin-resistant staphylococci (MRS) are increasingly being isolated in bovine mastitis. The aim of our study was to evaluate the occurrence of MRS in Finnish mastitis milk samples and characterize the MRS isolates using molecular methods.
  
  
  RESULTS
  Methicillin-resistant S. aureus (MRSA) was a rare finding in bovine mastitis in Finland. Only two out of 135 (1.5%) S. aureus isolates were positive for mec genes. One of these carried mecA and was of spa type t172, SCCmec type IV and ST375, and the other harboured mecC, being spa type t3256, and ST130. MRSA ST375 is common among human MRSA isolates in Finland, but this is the first report in the country of bovine mecC MRSA. In coagulase-negative staphylococci (CoNS) originating from bovine mastitis, methicillin resistance was more common. In the two CoNS collections studied, 5.2% (17/324) and 1.8% (2/110) of the isolates were mecA positive. Eighteen of these were methicillin-resistant S. epidermidis (MRSE), which were divided into 6 separate PFGE clusters. One pulsotype was detected in different parts of the country, indicating clonal spread. Most MRSE (13/18) were of SCCmec type IV, one was of type V and four were non-typeable. Comparison with a human staphylococcal database indicated that bovine MRSE strains were not closely related to human MRSE isolates.
  
  
  CONCLUSIONS
  The occurrence of MRS, especially MRSA, in bovine mastitis in Finland was low. Most methicillin-resistant bovine CoNS are MRSE, and we found evidence of a bovine MRSE strain that may spread clonally. This is the first report of a Finnish bovine isolate of MRSAmecC ST130. The study provides a baseline for further MRS monitoring.
authors.affiliation: Faculty of Veterinary Medicine, Department of Production Animal Medicine, University of Helsinki, Koetilantie 7, 00014 Helsinki, Finland. veera.gindonis@helsinki.fi.
authors.forename: Veera
authors.initials: V
authors.lastname: Gindonis
authors.forename: Suvi
authors.initials: S
authors.lastname: Taponen
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Myllyniemi
authors.forename: Satu
authors.initials: S
authors.lastname: Pyörälä
authors.forename: Suvi
authors.initials: S
authors.lastname: Nykäsenoja
authors.forename: Saara
authors.initials: S
authors.lastname: Salmenlinna
authors.forename: Laura
authors.initials: L
authors.lastname: Lindholm
authors.forename: Merja
authors.initials: M
authors.lastname: Rantala
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D005260:Female; D005387:Finland / Q000453:epidemiology; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000382:microbiology*; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*
chemical_list: D000900:Anti-Bacterial Agents; D008712:Methicillin