title: Genetic diversity of methicillin-resistant Staphylococcus aureus carrying type IV SCCmec in Orebro County and the western region of Sweden.
abstract: BACKGROUND
  Recent studies have shown a predominance of type IV SCCmec among the methicillin-resistant Staphylococcus aureus (MRSA) isolated in the low endemic areas of Orebro County and the western region of Sweden. However, many of these isolates were not possible to classify as existing subtypes IVa, IVb, IVc or IVd.
  
  
  METHODS
  We analysed 16 such MRSA isolates by multilocus sequence typing, spa typing, staphylocoagulase (SC) typing and detection of type IVg and IVh SCCmec. MRSA that remained as unknown type IV SCCmec were investigated by long-range PCR covering the J1 region; however, only two isolates were possible to amplify by PCR. The nucleotide sequences of the entire SCCmec of these two MRSA were determined. In addition, isolates that had unknown SC types were investigated by nucleotide sequencing of the coa genes.
  
  
  RESULTS
  Five of 16 isolates were classified as type IVg SCCmec, and four isolates had type IVh SCCmec. Two subtypes of type IV SCCmec shared J1 regions previously identified in other types of SCCmec, types I.2 and II.2. The novel elements were designated as type IVi and IVj SCCmec. In addition, the genetic backgrounds of these Swedish MRSA were diverse and constituted at least nine sequence types and eight SC types, including four new types of SC.
  
  
  CONCLUSIONS
  Type IV SCCmec is occurring in heterogeneous clones of MRSA in Sweden, and the majority of the type IV SCCmec were identified in community-acquired MRSA. We describe two novel subtypes of type IV SCCmec with common J1 regions shared by other types of SCCmec, which indicate that J1 regions occurred as primordial SCC.
authors.affiliation: Department of Clinical Microbiology, Orebro University Hospital, Orebro, Sweden.
authors.forename: Carolina
authors.initials: C
authors.lastname: Berglund
authors.forename: Teruyo
authors.initials: T
authors.lastname: Ito
authors.forename: Xiao Xue
authors.initials: XX
authors.lastname: Ma
authors.forename: Megumi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Shinya
authors.initials: S
authors.lastname: Watanabe
authors.forename: Bo
authors.initials: B
authors.lastname: Söderquist
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hiramatsu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D023061:Gene Order; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013548:Sweden / Q000453:epidemiology; D026801:Synteny
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial