Characterization of a Staphylococcus aureus USA300 protein signature using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
Staphylococcus aureus strain type USA300 is an important human pathogen. Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry has been used successfully for rapid identification of S. aureus at the genus and species levels. Here, it was hypothesized that MALDI-TOF could be used to identify USA300 organisms at the strain level. A genetic algorithm model using ClinProTools software (Bruker Daltonics) was built using 47 isolates of USA300 S. aureus and 77 non-USA300 S. aureus isolates. Three mass/charge peaks (5932, 6423 and 6592) were found to be discriminators between the groups of isolates. The model was validated using 224 test isolates: 197 of 224 test isolates were correctly classified as 'USA300 family' or 'non-USA300'. The sensitivity of the model was 0.87, with a specificity of 0.89, positive likelihood ratio of 8.19 and negative likelihood ratio of 0.15. The three-peak intensity MALDI-TOF model designed and tested in the current study can be used to rapidly identify USA300 family S. aureus isolates with reasonable sensitivity and specificity.
Department of Pediatrics, Eastern Virginia Medical School, Norfolk, VA 23510, USA.|Division of Infectious Diseases, Children's Hospital of The King's Daughters, Norfolk, VA 23510, USA.
Sarah R
SR
Boggs
Department of Microbiology and Immunology, Eastern Virginia Medical School, Norfolk, VA 23510, USA.
Lisa H
LH
Cazares
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29403, USA.
Richard
R
Drake
D001426:Bacterial Proteins / Q000032:analysis*; D015373:Bacterial Typing Techniques / Q000379:methods*; D006801:Humans; D020543:Proteome / Q000032:analysis*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013211:Staphylococcus aureus / Q000737:chemistry*
D001426:Bacterial Proteins; D020543:Proteome