Accurate differentiation of novel Staphylococcus argenteus from Staphylococcus aureus using MALDI-TOF MS.

Abstract

We evaluated a Staphylococcus argenteus-specific diagnostic profile of matrix-assisted laser desorption/ionization time-of-flight mass spectrometer for accurate identification of this novel bacterium. Staphylococcus argenteus was identified based on negative crtM gene and presence of specific sequence types. A classification model was generated by cluster analysis of matrix-assisted laser desorption/ionization time-of-flight mass spectrometer results and ClinProTools software for 25 S. argenteus and 25 methicillin-susceptible S. aureus (MSSA). The performance of the classification model was validated against 72 S. argenteus and 72 MSSA isolates. With cluster analysis and classification model, differentiation of 72 S. argenteus from 72 MSSA had 100.0% accuracy by chemical extraction method and 87.5% sensitivity and 100.0% specificity by direct smear method. The classification model could accurately differentiate S. argenteus from MSSA.