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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
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An invasive marker Staphylococcus epidermidis surface protein I (SesI) harboured by a ST239 methicillin-resistant

Yamuna Devi Bakthavatchalam1, Amala Arumugam1, Balaji Veeraraghavan1

  • 1Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.

Journal of Global Antimicrobial Resistance
|February 24, 2019
PubMed
Abstract

Insights

A novel sasX homologue, sesI, was identified in a methicillin-resistant Staphylococcus aureus (MRSA) ST239 strain, suggesting its transfer from Staphylococcus epidermidis. This finding highlights the spread of virulence factors between bacterial species.

Area of Science:

  • Microbiology and Molecular Biology
  • Genetics and Genomics
  • Infectious Diseases

Background:

  • The virulence factor sasX, located on the φSPβ prophage, has been recently identified in a methicillin-resistant Staphylococcus aureus (MRSA) ST239-SCCmecIII clone.
  • Understanding the genetic basis of MRSA virulence is crucial for developing effective treatment strategies.

Purpose of the Study:

  • To identify sesI, a homologue of the sasX gene, within an MRSA ST239 strain.
  • To investigate the potential dissemination of virulence factors between Staphylococcus species.

Main Methods:

  • Isolation and characterization of MRSA strain VB1490 from a patient with MRSA bacteraemia.
  • Staphylococcal cassette chromosome mec (SCCmec) typing and whole-genome shotgun sequencing of the isolate.
  • Phylogenetic analysis and amplification/sequencing of the sasX gene for allele homology.

Main Results:

  • The identified sasX gene in VB1490 showed higher similarity to the sesI gene of Staphylococcus epidermidis RP62A than to the sasX gene in other ST239 MRSA strains.
  • Whole-genome analysis confirmed the presence of the sasX gene on a φSPβ-like prophage with high sequence identity to that found in S. epidermidis RP62A.

Conclusions:

  • The findings suggest the horizontal transfer of the invasion-determining virulence factor, sesI, from Staphylococcus epidermidis to a ST239 MRSA strain.
  • This highlights a potential mechanism for the dissemination of virulence factors contributing to MRSA pathogenicity.
Keywords:
MRSAST239hVISAsasXsesI

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