Identification and discrimination of Staphylococcus aureus strains using matrix-assisted laser desorption/ionization-time of flight mass spectrometry

Proteomics. 2002 Jun;2(6):747-53. doi: 10.1002/1615-9861(200206)2:6<747::AID-PROT747>3.0.CO;2-V.


Staphylococcus aureus is an important human pathogen frequently resistant to a wide range of antibiotics. Methicillin-resistant S. aureus (MRSA) strains are common nosocomial pathogens that pose a world-wide problem. Rapid and accurate discrimination between methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus is essential for appropriate therapeutic management and timely intervention for infection control. We report here the application of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for monitoring the bacterial fingerprints expressed by two well characterized S. aureus strains ATCC 29213 (MSSA) and ATCC 43330 (MRSA). Consistent strain-specific data were obtained from subcultures analyzed over a period of three months as well as after changing the growth media from Mueller-Hinton to blood agar indicating the reliability of the method. The bacterial fingerprints of these two strains were compared to independent clinical isolates of S. aureus. A uniform signature profile for MRSA could not be identified. However, the bacterial fingerprints obtained proved to be specific for any given strain. This study demonstrates that MALDI-TOF MS is a powerful method for rapid identification of clonal strains of S. aureus, which might be useful for tracking nosocomial outbreaks of MRSA and for epidemiologic studies of infections diseases in general.

MeSH terms

  • Electrophoresis, Gel, Pulsed-Field
  • Humans
  • Methicillin Resistance*
  • Reproducibility of Results
  • Species Specificity
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / classification*
  • Staphylococcus aureus / metabolism*