Comparative analysis of phenol-soluble modulin production and Galleria mellonella killing by community-associated and healthcare-associated meticillin-resistant Staphylococcusaureus strains

J Med Microbiol. 2016 Dec;65(12):1429-1433. doi: 10.1099/jmm.0.000379. Epub 2016 Oct 26.

Abstract

Community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) have emerged globally and have been associated with more severe disease than healthcare-associated MRSA (HA-MRSA). The purpose of this study was to determine whether laboratory measures of virulence can distinguish dominant CA-MRSA clones from HA-MRSA clones. We compared the production of phenol-soluble modulins (PSMs) and ability to kill Galleria mellonella caterpillars for a range of CA- and HA-MRSA strains. Twenty-two HA-MRSA strains [ST22-IV (EMRSA-15), ST36-II (EMRSA-16) and ST239-III] and 26 CA-MRSA strains [ST1-IV (PVL+ USA400), ST1-IV (PVL-), ST8-IV (USA300), ST22-IV (PVL+), ST30-IV, ST59-IV and ST80-IV] were analysed. PSM production was measured using and compared using t-tests and ANOVA. A G mellonella (caterpillar) pathogenicity model was performed, and differences were compared using survival analysis and the log-rank test. There was no significant difference in overall PSM production between HA and CA strains (P=0.090), but there was significant variation between clones (P=0.003). G. mellonella caterpillar killing varied significantly by clone (P<0.001), and overall killing was greater for HA compared with CA clones (P=0.007). The increased acute virulence phenotype of CA-MRSA clones in humans is not associated with increased PSM production in vitro or increased killing in an in vivo caterpillar pathogenicity model.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Bacterial Toxins / biosynthesis*
  • Bacterial Toxins / metabolism
  • Community-Acquired Infections / microbiology*
  • Cross Infection / microbiology*
  • Disease Models, Animal
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / classification
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Methicillin-Resistant Staphylococcus aureus / pathogenicity*
  • Methicillin-Resistant Staphylococcus aureus / physiology*
  • Moths / microbiology*
  • Phenol
  • Solubility
  • Staphylococcal Infections / microbiology*
  • Virulence
  • Virulence Factors / biosynthesis
  • Virulence Factors / genetics

Substances

  • Bacterial Toxins
  • Virulence Factors
  • staphylococcal delta toxin
  • Phenol