RAPID IDENTIFICATION OF BACTERIA BY DIRECT MATRIX-ASSISTED LASER DESORPTION IONIZATION MASS-SPECTROMETRIC ANALYSIS OF WHOLE CELLS/

Several characteristic ions were observed during the direct analysis o f a variety of both gram-negative and grampositive intact bacterial ce lls by the matrix-assisted laser desorption/ionization mass spectromet ry (MALDI-MS) technique. The entire process, involving absolutely no s ample processing, could be completed in less than ten minutes. A numbe r of specific biomarkers, generated reproducibly for each type of cell from the corresponding mass spectrum, permitted the identification, a s well as the distinction, of pathogenic bacteria from their nonpathog enic counterparts. In addition, individual strains of a specific organ ism could also be differentiated easily. Some of these biomarkers corr espond to those observed earlier during the MALDI-MS analysis of prote in extracts of the same bacteria. This approach, which can yield valua ble data for rapid classification and detection of microorganisms, rep resents a substantial breakthrough for rapid screening of environmenta l as well as biological samples.