Bacillus anthracis seems to be the only obligate bacillus that is poisonous to vertebrates. Bacillus. But the article makes it sound as if it would be easy to bioengineer new obligate bacilli. Who knows whether a new such bacillus might not be at least as poisonous as bacillus anthracis?
Bacillus cereus can cause food poisoning and sometimes more serious disease in people with damaged immune systems, but is not considered a major threat. B. thuringiensis kills insects and is widely used as an environmentally friendly pesticide. But just a few changes could turn them into something as deadly as anthrax, the work suggests.