title: Methicillin-resistant Staphylococcus aureus genotyping using a small set of polymorphisms.
abstract: The aim of this study was to identify a set of genetic polymorphisms that efficiently divides methicillin-resistant Staphylococcus aureus (MRSA) strains into groups consistent with the population structure. The rationale was that such polymorphisms could underpin rapid real-time PCR or low-density array-based methods for monitoring MRSA dissemination in a cost-effective manner. Previously, the authors devised a computerized method for identifying sets of single nucleotide polymorphisms (SNPs) with high resolving power that are defined by multilocus sequence typing (MLST) databases, and also developed a real-time PCR method for interrogating a seven-member SNP set for genotyping S. aureus. Here, it is shown that these seven SNPs efficiently resolve the major MRSA lineages and define 27 genotypes. The SNP-based genotypes are consistent with the MRSA population structure as defined by eBURST analysis. The capacity of binary markers to improve resolution was tested using 107 diverse MRSA isolates of Australian origin that encompass nine SNP-based genotypes. The addition of the virulence-associated genes cna, pvl and bbp/sdrE, and the integrated plasmids pT181, pI258 and pUB110, resolved the nine SNP-based genotypes into 21 combinatorial genotypes. Subtyping of the SCCmec locus revealed new SCCmec types and increased the number of combinatorial genotypes to 24. It was concluded that these polymorphisms provide a facile means of assigning MRSA isolates into well-recognized lineages.
authors.affiliation: Cooperative Research Centre for Diagnostics, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Stephens
authors.affiliation: Cooperative Research Centre for Diagnostics, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Flavia
authors.initials: F
authors.lastname: Huygens
authors.affiliation: Cooperative Research Centre for Diagnostics, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Inman-Bamber
authors.affiliation: Cooperative Research Centre for Diagnostics, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Erin P
authors.initials: EP
authors.lastname: Price
authors.affiliation: Queensland Health Pathology Services, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Nimmo
authors.affiliation: Queensland Health Pathology Services, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Schooneveldt
authors.affiliation: Infection Management Services, Princess Alexandra Hospital and District Health Service, Brisbane, Australia.
authors.forename: Wendy
authors.initials: W
authors.lastname: Munckhof
authors.affiliation: Cooperative Research Centre for Diagnostics, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Giffard
mesh_terms: D001315:Australia; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D005838:Genotype; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D013211:Staphylococcus aureus / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics
chemical_list: C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D015534:Trans-Activators