DISCRIMINATION AMONG THE BACILLUS-CEREUS GROUP, IN COMPARISON TO BACILLUS-SUBTILIS, BY STRUCTURAL CARBOHYDRATE PROFILES AND RIBOSOMAL-RNA SPACER REGION PCR

The B. cereus group (B. anthracis, B. thuringiensis and B. cereus) and B. subtilis were physiologically, molecularly and chemically characte rized. Within the B. cereus group, strains grew anaerobically and were not lysozyme susceptible. B. anthracis strains were non-hemolytic unl ike B. cereus or B. thuringiensis. Only B. thuringiensis produced para sporal bodies. The 16S/23S rRNA spacer region was amplified giving 3 m ajor produces. The PCR products found in strains of B. subtilis were a pproximately 270, 400, and 430 nucleotides, with the corresponding ban ds in the B. cereus group at 250, 430, and 480. These patterns allowed B. subtilis to be differentiated from the other 3 species. Using gas chromatography-mass spectrometry, sugar profiles of vegetative cells w ere indistinguishable for B. cereus and B. thuringiensis. B. anthracis contained high levels of galactose which generally distinguished it f rom B. cereus/B. thuringiensis, while B. subtilis was distinguished fr om the B. cereus group by low mannosamine levels. Spore profiles diffe red from vegetative profiles in all 4 species. Like vegetative profile s, spore profiles were distinctive for B. cereus/B. thuringiensis, B. anthracis, and B. subtilis. B. cereus and B. thuringiensis spores both contained rhamnose, fucose, 2-O-methyl rhamnose and 3-O-methyl rhamno se, unlike B. anthracis spores which contained only rhamnose and 3-O-m ethyl rhamnose. B. subtilis strains were heterogeneous with some resem bling B. anthracis and others B. cereus/B. thuringiensis, although B. subtilis strains typically contained quinovose, The B. cereus group ca n be easily distinguished from B. subtilis, however, differentiation w ithin this group has always been problematic. Using carbohydrate profi ling, B. anthracis is readily distinguished from B. cereus (B. thuring iensis. Additionally, changes in carbohydrate composition between vege tative cells and spores occurs in the B. cereus group and B. subtilis.