Disclosed are methods and kits for identifying a virulent bacteria in a sample, which may include virulent bacteria belonging to the Bacillus genus (e.g., Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis). Typically, the methods include (a) reacting a mixture that includes, in addition to nucleic acid isolated from the sample, (i) at least one oligonucleotide capable of specifically hybridizing to nucleic acid of plasmid pX01; and (ii) at least one oligonucleotide capable of specifically hybridizing to nucleic acid of plasmid pX02. In addition, the mixture may include control nucleic acid. In the methods, nucleic acid of plasmid pX01 and nucleic acid of plasmid pX02 are detected, and optionally control nucleic acid is detected, thereby identifying the virulent bacteria.