Brevibacillus brevis (formerly known as Bacillus brevis[2]) is a Gram-positive, aerobic, motile, spore-forming, rod-shaped bacterium commonly found in soil, air, water, and decaying matter.

It is rarely associated with infectious diseases.

[3] The antibiotics gramicidin and tyrocidine were first isolated from it.

[4] Brevibacillus brevis is catalase positive, amylase negative, casein negative, gelatinase positive, and indole negative; most strains are citrate users.

Some strains are capable of oxidizing carbon monoxide aerobically.