Pyrolysis mass spectrometry studies on Bacillus anthracis, Bacillus cereus and their close relatives

Pyrolysis mass spectrometry was used to examine strains of B. anthracis, of B. cereus, of B. cereus either proven to cause emetic illness or connected with outbreaks of emetic food poisoning and of B. thuringiensis. Analysis of the data-set for all strains allowed differentiation between B. anthracis, the emetic B. cereus and B. thuringiensis but B. cereus strains could not be clearly discriminated. Removal of data for the B. thuringiensis and the emetic B. cereus strains, followed by re-analysis, allowed clear separation of the B. anthracis and B. cereus groups. Furthermore, PyMS was found to be capable of discriminating between some strains of B. anthracis, and demonstrating sub-groupings of others. This work provides further evidence of the ability of PyMS to distinguish rapidly between very closely related organisms and indicates its potential in epidemiology.