Rapid Microbial Identification by Mass Spectrometry

For microorganisms identification, protein mass patterns are compared within few minutes with commercially available reference databases (Bruker Daltonics for Microflex LT spectrometer), which include species-specific fingerprints of several bacterial and yeast isolates. Through a pattern matching procedure, mass peaks in the experimental spectra are matched with reference spectra included in the database; through this comparison, a numerical value is generated that allows accurate and rapid identification of the microorganisms to species level when score values obtained are in the range of the threshold values defined by the instrument manufacturer (score values higher than 2.0 for Bruker Biotyper software). A value higher than 2.0 is generally related to a valid identification to species level; a value between 2.0 and 1.7 is reliable identification to genus level. The identification process is performed in real-time, as soon as the sample is analyzed by the spectrometer [22 (link)].