Traditionally, culture, biochemical, and molecular methods have been at the forefront in the detection of Staphylococci, but recently diagnostic bacterial protein analysis by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has gained increasing acceptance as a rapid, simultaneous detection method. However, with the emergence of coagulase-negative Staphylococci (CoNS) infections in clinical studies there remains a need to accurately screen patients at the species, and even strain, level while also determining antibiotic resistance. A new bacterial profiling approach, developed in our lab, using fatty acids as diagnostic biomarkers rather than proteins was recently introduced. To demonstrate the utility of this method, we employed MALDI-TOF MS with CeO2 (MOLI-MS) as a saponification catalyst and matrix replacement coupled with multivariate statistics to analyze an extensive strain-level study of various Staphylococci species. Principal components analysis was used to classify 13 different species of Staphylococci as well as 10 S. aureus strains. Overall, the cross validation (CV) yielded a percent accuracy of 98% and 96% at the species and strain level respectively, while also revealing the capability to differentiate antibiotic resistant (MRSA) and sensitive (MSSA) strains of S. aureus.

Differentiation of Staphylococci by CeO2-facilitated fatty acid metal oxide laser ionization-mass spectrometry profiling

249th National Meeting (2015)

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