Real-time PCR to distinguish livestock-associated (ST398) from non-livestock-associated (methicillin-resistant) Staphylococcus aureus

Infection. 2013 Apr;41(2):339-46. doi: 10.1007/s15010-012-0319-5. Epub 2012 Sep 1.


Background: The Netherlands is one of the most densely populated countries in the world, with extensive livestock of pigs. In 2005, the emergence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was a fact, with a relatively high MRSA colonisation among pig farmers. These MRSA isolates mostly belonged to sequence type 398 (ST398). Compared to hospital-associated MRSA (HA-MRSA), severe infections due to LA-MRSA and transmission between individuals are still relatively rare. Therefore, LA-MRSA may warrant less stringent containment measures than HA-MRSA in hospital settings.

Results: The aim of this study was to develop a rapid diagnostic tool to distinguish LA-MRSA from non-LA-MRSA in aid of infection control. Here, we show that ST398 strains can be readily detected with real-time polymerase chain reaction (PCR). Analysis of a large panel of related and unrelated microorganisms confirmed that the real-time ST398 PCR (ST398-qPCR) assay does not cross-react with other microorganisms or with non-LA-S. aureus strains. ST398-qPCR analysis of MRSA isolates collected in 2010, 2011 and 2012 at the Jeroen Bosch Hospital (n = 275) showed that an average of 78 % of MRSA belonged to sequence type ST398.

Conclusion: We conclude that the ST398 real-time PCR is a reliable assay to detect LA-S. aureus and anticipate that the use of this assay can prevent the unnecessary closing of hospital wards, which may lead to substantial savings for the health care system.

MeSH terms

  • Animals
  • Bacterial Typing Techniques
  • Cross Infection / diagnosis
  • Cross Infection / transmission
  • Cross Reactions
  • DNA, Bacterial / analysis
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / classification*
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Netherlands
  • Real-Time Polymerase Chain Reaction / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Staphylococcal Infections / diagnosis*
  • Swine / microbiology


  • DNA, Bacterial