THE CHARACTERIZATION OF MICROORGANISMS BY MATRIX-ASSISTED-LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY/

A variety of gram-positive and gram-negative intact bacterial cells ha ve been analysed by matrix-assisted laser desorption/ionization mass s pectrometry (MALDI-MS) and shown to provide fingerprint mass spectra w ith discrete peaks being observed over the mass range from 3 to 40 kDa , The spectra show both more peaks and peaks at a higher mass/charge r atio than have hitherto been reported for these micro-organisms and wo uld appear to provide a profile of cellular proteinaceous material, Th e spectra are shown to be reproducible over variable time periods of u p to three months and factors affecting reproducibility pre discussed, The procedure, which requires minimal sample preparation, yields resu lts in 30-40 minutes and allows visual identification of species-and s train-specific biomarkers for the characterization of the organisms. T he importance of accurately defining sample preparation methodologies is central to the ability of the technique to generate reliable and re producible data. (C) 1998 John Wiley & Sons, Ltd.