A Simple and Safe Protocol for Preparing Brucella Samples for Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Analysis

Abstract

We describe a simple protocol to inactivate the biosafety level 3 (BSL3) pathogens Brucella prior to their analysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. This method is also effective for several other bacterial pathogens and allows storage, and eventually shipping, of inactivated samples; therefore, it might be routinely applied to unidentified bacteria, for the safety of laboratory workers.

FIG 1

Representative MALDI-TOF MS spectrum obtained for Brucella melitensis strain 16M that had been inactivated using the solvent-based protocol. Resolution (Resol.) values and signal/noise (S/N) ratios for the main masses are given in the table. Int., intensity.

FIG 2

MALDI-TOF MS spectra for Brucella melitensis strain 16M samples that had been stored in solvent at 4°C or 25°C for up to 2 weeks before analysis. Shown are the number of successful identifications/number of spectra analyzed, as well as the rate of success. For each condition, a representative spectrum is also shown.