Panton-Valentine leukocidin-positive Staphylococcus aureus in Ireland from 2002 to 2011: 21 clones, frequent importation of clones, temporal shifts of predominant methicillin-resistant S. aureus clones, and increasing multiresistance

J Clin Microbiol. 2014 Mar;52(3):859-70. doi: 10.1128/JCM.02799-13. Epub 2013 Dec 26.

Abstract

There has been a worldwide increase in community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) infections. CA-MRSA isolates commonly produce the Panton-Valentine leukocidin toxin encoded by the pvl genes lukF-PV and lukS-PV. This study investigated the clinical and molecular epidemiologies of pvl-positive MRSA and methicillin-susceptible S. aureus (MSSA) isolates identified by the Irish National MRSA Reference Laboratory (NMRSARL) between 2002 and 2011. All pvl-positive MRSA (n=190) and MSSA (n=39) isolates underwent antibiogram-resistogram typing, spa typing, and DNA microarray profiling for multilocus sequence type, clonal complex (CC) and/or sequence type (ST), staphylococcal cassette chromosome mec type assignment, and virulence and resistance gene detection. Where available, patient demographics and clinical data were analyzed. The prevalence of pvl-positive MRSA increased from 0.2% to 8.8%, and that of pvl-positive MSSA decreased from 20% to 2.5% during the study period. The pvl-positive MRSA and MSSA isolates belonged to 16 and 5 genotypes, respectively, with CC/ST8-MRSA-IV, CC/ST30-MRSA-IV, CC/ST80-MRSA-IV, CC1/ST772-MRSA-V, CC30-MSSA, CC22-MSSA, and CC121-MSSA predominating. Temporal shifts in the predominant pvl-positive MRSA genotypes and a 6-fold increase in multiresistant pvl-positive MRSA genotypes occurred during the study period. An analysis of patient data indicated that pvl-positive S. aureus strains, especially MRSA strains, had been imported into Ireland several times. Two hospital and six family clusters of pvl-positive MRSA were identified, and 70% of the patient isolates for which information was available were from patients in the community. This study highlights the increased burden and changing molecular epidemiology of pvl-positive S. aureus in Ireland over the last decade and the contribution of international travel to the influx of genetically diverse pvl-positive S. aureus isolates into Ireland.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Toxins / genetics*
  • Child
  • Child, Preschool
  • Cluster Analysis
  • Exotoxins / genetics*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Ireland / epidemiology
  • Leukocidins / genetics*
  • Male
  • Microarray Analysis
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Epidemiology
  • Molecular Typing*
  • Multilocus Sequence Typing
  • Prevalence
  • Staphylococcal Infections / epidemiology*
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification*
  • Virulence Factors / genetics
  • Young Adult

Substances

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