The RM Test for Determining Methicillin-Resistant Staphylococcus aureus Lineages

  • Jodi A. Lindsay
  • Julia M.-L. Sung
Part of the Methods in Molecular Biology book series (MIMB, volume 642)


Staphylococcus aureus lineages evolve independently and differ in hundreds of genes. Identification of lineages can be useful for epidemiological typing and infection control at the local or global level, and can also be useful when investigating differences in pathogenesis between strains. MLST (multilocus sequence typing) and spa typing (polymorphisms in the protein A gene) are useful methods for identifying lineages but can be time-consuming and expensive. Here, we describe a method for identifying lineages using PCR, which is very easy to perform and can generate results within hours. It can also be adapted to commercial or real-time platforms. The RM (restriction modification) test is based on unique sequences found in each lineage that determine the specificity of an RM system, which detects and digests foreign DNA, thereby controlling the independent evolution of the lineages; thus, it is the ideal single gene to target for a rapid lineage test.

Key words

Methicillin-resistant Staphylococcus aureus MRSA Restriction modification RM test Lineages Typing PCR 



We are indebted to Joshua Cockfield who developed these tests, and trained many colleagues in their use. This project was funded by a joint grant to JAL and Jonathan Edgeworth, from the Guy’s and St Thomas’ Hospital Charitable Foundation.


  1. 1.
    Gordon RJ, Lowy FD (2008) Pathogenesis of methicillin-resistant Staphylococcus aureus infection. Clin Infect Dis 46(Suppl 5):S350–S359CrossRefPubMedGoogle Scholar
  2. 2.
    Lindsay JA, Holden MT (2006) Understanding the rise of the superbug: investigation of the evolution and genomic variation of Staphylococcus aureus. Funct Integr Genomics 6:186–201CrossRefPubMedGoogle Scholar
  3. 3.
    Robinson DA, Enright MC (2003) Evolutionary models of the emergence of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 47:3926–3934CrossRefPubMedGoogle Scholar
  4. 4.
    Ito T, Kuwahara K, Hiramatsu K (2007) Staphylococcal cassette chromosome mec (SCCmec) analysis of MRSA. Methods Mol Biol 391:87–102CrossRefPubMedGoogle Scholar
  5. 5.
    Gould IM (2005) The clinical significance of methicillin-resistant Staphylococcus aureus. J Hosp Infect 61:277–282CrossRefPubMedGoogle Scholar
  6. 6.
    Sievert DM, Rudrik JT, Patel JB, McDonald LC, Wilkins MJ, Hageman JC (2008) Vancomycin-resistant Staphylococcus aureus in the United States, 2002–2006. Clin Infect Dis 46:668–674CrossRefPubMedGoogle Scholar
  7. 7.
    Loeffler A, Boag AK, Sung J, Lindsay JA, Guardabassi L, Dalsgaard A, Smith H, Stevens KB, Lloyd DH (2005) Prevalence of methicillin-resistant Staphylococcus aureus among staff and pets in a small animal referral hospital in the UK. J Antimicrob Chemother 56:692–697CrossRefPubMedGoogle Scholar
  8. 8.
    van Loo I, Huijsdens X, Tiemersma E, de Neeling A, van de Sande-Bruinsma N, Beaujean D, Voss A, Kluytmans J (2007) Emergence of methicillin-resistant Staphylococcus aureus of animal origin in humans. Emerg Infect Dis 13:1834–1839PubMedGoogle Scholar
  9. 9.
    Lindsay JA, Moore CE, Day NP, Peacock SJ, Witney AA, Stabler RA, Husain SE, Butcher PD, Hinds J (2006) Microarrays reveal that each of the ten dominant lineages of Staphylococcus aureus has a unique combination of surface-associated and regulatory genes. J Bacteriol 188:669–676CrossRefPubMedGoogle Scholar
  10. 10.
    Cockfield JD, Pathak S, Edgeworth JD, Lindsay JA (2007) Rapid determination of hospital-acquired meticillin-resistant Staphy-lococcus aureus lineages. J Med Microbiol 56:614–619CrossRefPubMedGoogle Scholar
  11. 11.
    Enright MC, Day NP, Davies CE, Peacock SJ, Spratt BG (2000) Multilocus sequence typing for characterization of methicillin-resistant and methicillin-susceptible clones of Staphylococcus aureus. J Clin Microbiol 38:1008–1015PubMedGoogle Scholar
  12. 12.
    Harmsen D, Claus H, Witte W, Rothgänger J, Claus H, Turnwald D, Vogel U (2003) Typing of methicillin-resistant Staphylococcus aureus in a university hospital setting by using novel software for spa repeat determination and database management. J Clin Microbiol 41:5442–5448CrossRefPubMedGoogle Scholar
  13. 13.
    Waldron DE, Lindsay JA (2006) Sau1: a novel lineage-specific type I restriction-modification system that blocks horizontal gene transfer into Staphylococcus aureus and between S. aureus isolates of different lineages. J Bacteriol 188:5578–5585CrossRefPubMedGoogle Scholar
  14. 14.
    Robinson DA, Enright MC (2004) Evolution of Staphylococcus aureus by large chromosomal replacements. J Bacteriol 186:1060–1064CrossRefPubMedGoogle Scholar
  15. 15.
    Moore PC, Lindsay JA (2001) Genetic variation among hospital isolates of methicillin-sensitive Staphylococcus aureus: evidence for horizontal transfer of virulence genes. J Clin Microbiol 39:2760–2767CrossRefPubMedGoogle Scholar
  16. 16.
    Lina G, Piémont Y, Godail-Gamot F, Bes M, Peter MO, Gauduchon V, Vandenesch F, Etienne J (1999) Involvement of Panton-Valentine leukocidin-producing Staphylococcus aureus in primary skin infections and pneumonia. Clin Infect Dis 29:1128–1132CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Jodi A. Lindsay
    • 1
  • Julia M.-L. Sung
    • 2
  1. 1.Department Cellular & Molecular Medicine, Centre for InfectionSt George’s University of LondonLondonUK
  2. 2.Division of Cell Biology and ImagingNational Institute for Biological Standards and ControlHertfordshireUK

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