title: A novel hybrid SCCmec-mecC region in Staphylococcus sciuri.
abstract: OBJECTIVE
  Methicillin resistance in Staphylococcus spp. results from the expression of an alternative penicillin-binding protein 2a (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA known as mecC (formerly mecALGA251) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified two Staphylococcus sciuri subsp. carnaticus isolates from bovine infections that harbour three different mecA homologues: mecA, mecA1 and mecC.
  
  
  METHODS
  We subjected the two isolates to whole-genome sequencing to further understand the genetic context of the mec-containing region. We also used PCR and RT-PCR to investigate the excision and expression of the SCCmec element and mec genes, respectively.
  
  
  RESULTS
  Whole-genome sequencing revealed a novel hybrid SCCmec region at the orfX locus consisting of a class E mec complex (mecI-mecR1-mecC1-blaZ) located immediately downstream of a staphylococcal cassette chromosome mec (SCCmec) type VII element. A second SCCmec attL site (attL2), which was imperfect, was present downstream of the mecC region. PCR analysis of stationary-phase cultures showed that both the SCCmec type VII element and a hybrid SCCmec-mecC element were capable of excision from the genome and forming a circular intermediate. Transcriptional analysis showed that mecC and mecA, but not mecA1, were both expressed in liquid culture supplemented with oxacillin.
  
  
  CONCLUSIONS
  Overall, this study further highlights that a range of staphylococcal species harbour the mecC gene and furthers the view that coagulase-negative staphylococci associated with animals may act as reservoirs of antibiotic resistance genes for more pathogenic staphylococcal species.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Ewan M
authors.initials: EM
authors.lastname: Harrison
authors.forename: Gavin K
authors.initials: GK
authors.lastname: Paterson
authors.forename: Matthew T G
authors.initials: MT
authors.lastname: Holden
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Ba
authors.forename: Joana
authors.initials: J
authors.lastname: Rolo
authors.forename: Fiona J E
authors.initials: FJ
authors.lastname: Morgan
authors.forename: Bruno
authors.initials: B
authors.lastname: Pichon
authors.forename: Angela
authors.initials: A
authors.lastname: Kearns
authors.forename: Ruth N
authors.initials: RN
authors.lastname: Zadoks
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
authors.forename: Julian
authors.initials: J
authors.lastname: Parkhill
authors.forename: Mark A
authors.initials: MA
authors.lastname: Holmes
mesh_terms: D000818:Animals; D002417:Cattle; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020869:Gene Expression Profiling; D023061:Gene Order; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D005838:Genotype; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013210:Staphylococcus / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial
keywords: MRSA; mecA; β-lactams