Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspicuous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound, and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia. These two strains, when analyzed by amplified fragment length polymorphism within a collection of over 300 of B. cereus, B. thuringiensis, and B. anthracis isolates, appear closely related to B. anthracis. The B. cereus E33L isolate appears to be the nearest relative to B. anthracis identified thus far. Whole-genome sequencing of B. thuringiensis 97-27and B. cereus E33L was undertaken to identify shared and unique genes among these isolates in comparison to the genomes of pathogenic strains B. anthracis Ames and B. cereus G9241 and nonpathogenic strains B. cereus ATCC 10987 and B. cereus ATCC 14579. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms.While Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related members of the B. cereus group (22), individual isolates exhibit differences in terms of host range and virulence. B. anthracis is the causal agent of anthrax, a zoonotic disease that can be lethal to humans. B. cereus is a ubiquitous soil organism and an opportunistic human pathogen most commonly associated with food poisoning (10). B. thuringiensis is an insect pathogen that is widely used as a biopesticide (36). Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound (17), and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia (P. C. B. Turnbull, personal communication). To facilitate the comparison of these two isolates with other members of the B. cereus group, we compiled a core genome of over 3,900 B. cereus group genes. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms (see Table 1, below), supporting the idea that differential regulation modulates virulence rather than simple acquisition of virulence factor genes. Our analysis of the genome sequences of B. thuringiensis 97-27 and B. cereus E33L provides insight into the evolutionary relationships among these B. cereus group organisms, as well as the molecular mechanisms contributing to their host range and virulence. MATERIALS AND METHODSSequencing of the B. thuringiensis 97-27 and B. cereus E33L genomes. The random shotgun method of cloning, sequencing, an...

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Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (E. Schnepf, N. Crickmore, J. Van Rie, D. Lereclus, J. Baum, J. Feitelson, D. R. Zeigler, and D. H. Dean, Microbiol. Mol. Biol. Rev. 62:775-806, 1998). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (L. Radnedge, P. Agron, K. Hill, P. Jackson, L. Ticknor, P. Keim, and G. Andersen, Appl. Environ. Microbiol. 69:2755-2764, 2003).