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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
14:04

Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Published on: May 8, 2013

Identification and characterization of phage variants of a strain of epidemic methicillin-resistant Staphylococcus

G L O'Neill1, S Murchan, A Gil-Setas

  • 1Laboratory of Hospital Infection, Central Public Health Laboratory, London, NW9 5HT, United Kingdom.

Journal of Clinical Microbiology
|April 3, 2001
PubMed

Insights

Epidemic methicillin-resistant Staphylococcus aureus (EMRSA)-15 strains in the UK show genetic diversity. Pulsed-field gel electrophoresis (PFGE) revealed variations, highlighting the need to analyze profiles as a continuum.

Area of Science:

  • Microbiology
  • Genetics
  • Epidemiology

Background:

  • EMRSA-15 is a significant epidemic strain of methicillin-resistant Staphylococcus aureus in the UK.
  • Original EMRSA-15 strains had specific phage lysis and toxin profiles (enterotoxin C positive, urease negative).
  • Emergence of EMRSA-15 variants with broader phage patterns necessitates further characterization.

Purpose of the Study:

  • To compare classical EMRSA-15 and its phage variants using PFGE and molecular typing.
  • To assess the accuracy of phage typing for EMRSA-15 identification.
  • To investigate the genetic basis of enterotoxin C production in EMRSA-15.

Main Methods:

  • Pulsed-field gel electrophoresis (PFGE) with SmaI macrorestriction profiling.
  • Urease and enterotoxin C production assays.
  • Southern blotting to examine the enterotoxin C gene locus.

Main Results:

  • PFGE identified 22 distinct profiles among 145 EMRSA-15 isolates, with significant overlap and variation.
  • Phage typing misidentified 8% of isolates, misclassifying them as non-EMRSA-15.
  • The enterotoxin C gene appears located on a mobile DNA segment; enterotoxin C-negative strains often reacted with phage 81.

Conclusions:

  • PFGE is a robust method for characterizing EMRSA-15, revealing a continuum of genetic profiles.
  • Phage typing alone has limitations in accurately identifying EMRSA-15 strains.
  • Understanding the genetic diversity and mobile elements within EMRSA-15 is crucial for tracking its spread.

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