PCR-RFLP analysis of the coagulase gene of Staphylococcus aureus: application to the differentiation of epidemic and sporadic methicillin-resistant strains

J Hosp Infect. 1999 Jul;42(3):205-12. doi: 10.1053/jhin.1999.0595.

Abstract

Preventing cross-infection with epidemic strains of methicillin-resistant Staphylococcus aureus (MRSA) requires effective control measures. These call for simple, rapid, discriminatory and reproducible methods for typing this pathogen. In this study 140 isolates/strains from 105 hospitals in England and Wales, representing 72 diverse phage types, were analysed by bacteriophage typing and PCR coagulase (coa) gene restriction fragment length polymorphism (RFLP). Isolates gave a coa gene PCR product that was either 660 base pairs (bp), 603 bp or 547 pb in size. The PCR products were digested with Alu I and Cfo I, and the fragments separated by gel electrophoresis. Eight coa gene RFLP patterns, numbered 1 to 8, were observed. Pattern 3 was most common (N = 25 isolates), followed by patterns 2 and 5 (18 isolates each), pattern 1 (14 isolates), pattern 4 (11 isolates), pattern 7 (10 isolates), pattern 8 (eight isolates) and pattern 6 (six isolates). Isolates of the same phage type often gave different coa gene RFLP patterns, and the patterns within the epidemic types EMRSA-03, EMRSA-15 and EMRSA-16 were heterogeneous. Thus, representatives of EMRSA-03 were subtyped to coa RFLP patterns 1 and 2, those of EMRSA-05 to coa RFLP patterns 1, 2, 7 and 8, and those for EMRSA-16 to coa RFLP patterns 2, 3, 4, 5 and 6. The range of patterns within single phage types of S. aureus could help to discriminate between isolates/strains, and in a hierarchical approach coa gene RFLP could occupy an intermediate position between phage typing and pulsed-field gel electrophoresis (PFGE).

MeSH terms

  • Bacteriophage Typing
  • Chromosomes, Bacterial / genetics
  • Coagulase / genetics*
  • DNA, Bacterial / genetics
  • England
  • Genes, Bacterial / genetics*
  • Humans
  • Methicillin Resistance / genetics*
  • Polymerase Chain Reaction / methods*
  • Polymorphism, Restriction Fragment Length*
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / enzymology
  • Staphylococcus aureus / genetics*
  • Staphylococcus aureus / isolation & purification
  • Wales

Substances

  • Coagulase
  • DNA, Bacterial