Which bacterium produces the botulinum toxin responsible for botulism?

Clostridium botulinum produces the botulinum toxin responsible for botulism.

Clostridium botulinum is an anaerobic, spore-forming bacterium found in soil and aquatic environments. Under suitable conditions, some strains produce botulinum neurotoxins, which block the release of acetylcholine at neuromuscular junctions. The resulting illness causes weakness and descending, flaccid paralysis.

Foodborne botulism can occur when toxin forms in improperly processed food, especially in low-acid foods sealed without adequate heating. Infant botulism has a different route: spores can grow in an infant’s intestine. Wound botulism occurs when spores contaminate damaged tissue.

Botulinum toxin is extremely dangerous in uncontrolled exposure, but carefully purified and diluted forms are also used medically and cosmetically. It is important not to confuse botulism with tetanus. Clostridium tetani produces a toxin that causes rigid muscle spasms, whereas C. botulinum toxin generally causes flaccid paralysis.