Fig. 6.

Rapid identification of potential bioterrorism agents in the clinical laboratory.

The spectral display of a Brucella melitensis isolate, a biosafety level 3 (BSL-3) and Category B bioterrorism agent classified by the US Center for Disease Control and Prevention (CDC). Showing the acquired mass spectra range from 2,000 to 20,000 m/z, which corresponds to a mass range of 2 to 20 kDa as most of the ions produced by MALDI are of charge 1⁺. It should be noted that, unlike chemical identification, the exact protein or peptide fragment identity of the m/z peaks is often not known; usually, only a database search of standard spectra from definitively identified organisms is performed and no attempt is made to identify individual fragments. This seemingly simply approach nevertheless allows the early and rapid identification of microorganisms, hence facilitate clinical management and epidemiological investigation. The MALDI-TOF biotyping method also reduces the potential risks to the laboratory professional as the matrix solvent often inactivates the organism (see text), and that the minimal handling steps further reduces aerosolization and infective risks.