title: Distribution and characterization of staphylococcal interspersed repeat units (SIRUs) and potential use for strain differentiation.
abstract: Variable-number tandem repeats (VNTRs) have been shown to be a powerful tool in the determination of evolutionary relationships and population genetics of bacteria. The sequencing of a number of Staphylococcus aureus genomes has allowed the identification of novel VNTR sequences in S. aureus, which are similar to those used in the study of the evolution of Mycobacterium tuberculosis clades. Seven VNTRs, termed staphylococcal interspersed repeat units (SIRUs), distributed around the genome are described, occurring in both unique and multiple sites, and varying in length from 48 to 159 bp. Variations in copy numbers were observed in all loci, within both the sequenced genomes and the UK epidemic methicillin-resistant S. aureus (EMRSA) isolates. Clonally related UK EMRSA isolates were clustered using SIRUs, which provided a greater degree of discrimination than multi-locus sequence typing, indicating that VNTRs may be a more appropriate evolutionary marker for studying transmission events and the geographical spread of S. aureus clades.
authors.affiliation: West Midlands Public Health Laboratory, Health Protection Agency, Heartlands Hospital, Bordesley Green East, Birmingham B9 5SS, UK. Katie.Hardy@heartsol.wmids.nhs.uk
authors.forename: K J
authors.initials: KJ
authors.lastname: Hardy
authors.forename: D W
authors.initials: DW
authors.lastname: Ussery
authors.forename: B A
authors.initials: BA
authors.lastname: Oppenheim
authors.forename: P M
authors.initials: PM
authors.lastname: Hawkey
mesh_terms: D015373:Bacterial Typing Techniques; D001483:Base Sequence; D004196:Disease Outbreaks; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D006801:Humans; D016106:Methicillin Resistance; D018598:Minisatellite Repeats / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D006113:United Kingdom / Q000453:epidemiology