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Published on: February 19, 2019

Emergence, spread, and characterization of phage variants of epidemic methicillin-resistant Staphylococcus aureus 16

S Murchan1, H M Aucken, G L O'neill

  • 1Laboratory of Healthcare-Associated Infection, Specialist and Reference Microbiology Division, Health Protection Agency, London, UK.

Journal of Clinical Microbiology
|November 6, 2004
PubMed

Insights

Epidemic methicillin-resistant Staphylococcus aureus 16 (EMRSA-16) spread from a single hospital to 136 others within 2 years, primarily affecting males aged 60-80. This study details its characteristics and genetic variants.

Area of Science:

  • Medical Microbiology
  • Infectious Diseases
  • Epidemiology

Background:

  • Epidemic methicillin-resistant Staphylococcus aureus (EMRSA) strains, particularly EMRSA-16 and EMRSA-15, are significant healthcare-associated pathogens in the UK, Europe, and the US.
  • Understanding the transmission dynamics and genetic characteristics of prevalent EMRSA strains is crucial for effective infection control.

Purpose of the Study:

  • To document the interhospital and intraregional spread of EMRSA-16 from its initial hospital emergence.
  • To characterize the clinical and microbiological features of EMRSA-16 and its phage variants.
  • To investigate the genetic relatedness of EMRSA-16 isolates using molecular typing methods.

Main Methods:

  • Phage typing and pulsed-field gel electrophoresis (PFGE) for molecular characterization of EMRSA-16 isolates.
  • Antimicrobial susceptibility testing, urease production assays, and PCR for toxin gene detection (sea, tst).
  • Analysis of 129 clinical isolates from 52 hospitals collected between March 1998 and April 1999.

Main Results:

  • EMRSA-16 demonstrated significant spread to 136 hospitals within 18 months of its initial detection.
  • The strain was more prevalent in males aged 60-80 years and frequently isolated from sputum and throat samples.
  • PFGE analysis identified 29 distinct profiles, indicating genetic diversity among EMRSA-16 isolates, including phage variants.
  • Key characteristics included carriage of enterotoxin A (sea) and toxic shock syndrome toxin (tst) genes, and urease production.

Conclusions:

  • EMRSA-16 exhibits a propensity for rapid interhospital and regional dissemination.
  • Molecular typing methods like PFGE are essential for tracking the spread and understanding the genetic relationships of EMRSA strains.
  • The emergence of phage variants highlights the evolving nature of EMRSA strains and the need for ongoing surveillance.

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