Criteria for the identification of Bacillus anthracis.

The identification of Bacillus anthracis involves its differentiation from other aerobic sporeformers, particularly Bacillus cereus. Smith et al. (1952), in a study of aerobic sporeforming bacteria, concluded that B. anthracis is a pathogenic variety of B. cereus. They also stated that strains of B. anthracis which had lost their virulence could not be differentiated from B. cereus. This apparent relationship between B. anthracis and B. cereus was supported by Brown et al. (1958). Burdon (1956) listed characteristics for the identification of pathogenic strains of B. anthracis, but indicated that attenuated and avirulent strains presented properties closely approaching those of B. cereus. The report which follows presents data showing that the combination of a few simple tests serves to identify both virulent and avirulent strains of B. anthracis and in addition differentiates them from B. cereus, Bacillus cereus var. mycoides, Bacillus thuringiensis, and Bacillus subtilis. Data will be presented to show that pathogenic strains of B. anthracis which lose their pathogenicity remain B. anthracis and can be differentiated from B. cereus and the other sporeformers tested. Such a differentiation is of taxonomic and medical importance.