High diversity of Panton-Valentine leukocidin-positive, methicillin-susceptible isolates of Staphylococcus aureus and implications for the evolution of community-associated methicillin-resistant S. aureus

Clin Microbiol Infect. 2007 Dec;13(12):1157-64. doi: 10.1111/j.1469-0691.2007.01833.x. Epub 2007 Oct 19.

Abstract

In total, 100 Staphylococcus aureus isolates from diverse cases of skin and soft-tissue infection at a university hospital in Saxony, Germany, were characterised using diagnostic microarrays. Virulence factors, including Panton-Valentine leukocidin (PVL), were detected and the isolates were assigned to clonal groups. Thirty isolates were positive for the genes encoding PVL. Only three PVL-positive methicillin-resistant S. aureus (MRSA) isolates were found, two of which belonged to European clone ST80-MRSA IV and one to USA300 strain ST8-MRSA IV. The remaining methicillin-susceptible PVL-positive isolates belonged to a variety of different multilocus sequence types. The predominant strains were agrI/ST22, agrII/CC5, agrIII/CC30 and agrIV/ST121. In order to check for possible bias caused by regional or local outbreak strains, an additional 18 methicillin-susceptible, PVL-positive isolates from the UK were tested. Approximately two-thirds of the UK isolates belonged to types that also comprised approximately two-thirds of the isolates from Saxony. Some methicillin-susceptible PVL-positive isolates (agrI/ST152, agrIII/ST80 and agrIII/ST96) closely resembled known epidemic community-acquired MRSA (CaMRSA) strains. These findings indicate that the current rise in PVL-positive CaMRSA could be caused by the dissemination of novel SCCmec elements among pre-existing PVL-positive strains, rather than by the spread of PVL phages among MRSA strains.

MeSH terms

  • Bacterial Toxins / genetics*
  • Bacterial Typing Techniques
  • Community-Acquired Infections / microbiology*
  • Evolution, Molecular*
  • Exotoxins / genetics*
  • Gene Transfer, Horizontal
  • Genetic Variation*
  • Genotype
  • Germany
  • Humans
  • Leukocidins / genetics*
  • Methicillin Resistance / genetics*
  • Microarray Analysis
  • Oligonucleotide Array Sequence Analysis
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / classification*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification
  • Virulence Factors / genetics

Substances

  • Bacterial Toxins
  • Exotoxins
  • Leukocidins
  • Panton-Valentine leukocidin
  • Virulence Factors