Cell Wall Carbohydrate Compositions of Strains from the Bacillus cereus Group of Species Correlate with Phylogenetic Relatedness

Members of theBacillus cereus group contain cell wall carbohydrates that vary in their glycosyl compositions. Recent multilocus sequence typing (MLST) refined the relatedness ofB. cereus group members by separating them into clades and lineages. Based on MLST, we selected severalB. anthracis ,B. cereus , andB. thuringiensis strains and compared their cell wall carbohydrates. The cell walls of differentB. anthracis strains (clade 1/Anthracis) were composed of glucose (Glc), galactose (Gal),N -acetyl mannosamine (ManNAc), andN -acetylglucosamine (GlcNAc). In contrast, the cell walls from clade 2 strains (B. cereus type strain ATCC 14579 andB. thuringiensis strains) lacked Gal and containedN -acetylgalactosamine (GalNAc). TheB. cereus clade 1 strains had cell walls that were similar in composition toB. anthracis in that they all contained Gal. However, the cell walls from some clade 1 strains also contained GalNAc, which was not present inB. anthracis cell walls. Three recently identified clade 1 strains ofB. cereus that caused severe pneumonia, i.e., strains 03BB102, 03BB87, and G9241, had cell wall compositions that closely resembled those of theB. anthracis strains. It was also observed thatB. anthracis strains cell wall glycosyl compositions differed from one another in a plasmid-dependent manner. When plasmid pXO2 was absent, the ManNAc/Gal ratio decreased, while the Glc/Gal ratio increased. Also, deletion ofatxA , a global regulatory gene, from a pXO2− strain resulted in cell walls with an even greater level of Glc.