Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis - One species on the basis of genetic evidence

Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are members of the Bacillus cereus group of bacteria, demonstrating widely different p henotypes and pathological effects. B. anthracis causes the acute fatal dis ease anthrax and is a potential biological weapon due to its high toxicity. B. thuringiensis produces intracellular protein crystals toxic to a wide n umber of insect larvae and is the most commonly used biological pesticide w orldwide. B. cereus is a probably ubiquitous soil bacterium and an opportun istic pathogen that is a common cause of food poisoning. In contrast to the differences in phenotypes, we show by multilocus enzyme electrophoresis an d by sequence analysis of nine chromosomal genes that B. anthracis should b e considered a lineage of B. cereus. This determination is not only a forma l matter of taxonomy but may also have consequences with respect to virulen ce and the potential of horizontal gene transfer within the B. cereus group .