title: Prevalence and characterization of human mecC methicillin-resistant Staphylococcus aureus isolates in England.
abstract: OBJECTIVE
  There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates.
  
  
  METHODS
  Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011-12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits.
  
  
  RESULTS
  Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%-0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays.
  
  
  CONCLUSIONS
  mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK.
authors.forename: G K
authors.initials: GK
authors.lastname: Paterson
authors.forename: F J E
authors.initials: FJ
authors.lastname: Morgan
authors.forename: E M
authors.initials: EM
authors.lastname: Harrison
authors.forename: E J P
authors.initials: EJ
authors.lastname: Cartwright
authors.forename: M E
authors.initials: ME
authors.lastname: Török
authors.forename: R N
authors.initials: RN
authors.lastname: Zadoks
authors.forename: J
authors.initials: J
authors.lastname: Parkhill
authors.forename: S J
authors.initials: SJ
authors.lastname: Peacock
authors.forename: M A
authors.initials: MA
authors.lastname: Holmes
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D004739:England / Q000453:epidemiology; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification*; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial
keywords: MRSA; S. aureus; mec genes; surveillance