Botulinum neurotoxin

Definition

Botulinum neurotoxin is a potent toxin produced by the bacterium Clostridium botulinum. It causes the paralytic illness botulism by blocking neurotransmitter release at neuromuscular junctions.

5 Must Know Facts For Your Next Test

1. Botulinum neurotoxin is one of the most lethal substances known, with a lethal dose in humans estimated at around 1 nanogram per kilogram.
2. The toxin functions by cleaving SNARE proteins, which are essential for neurotransmitter vesicle fusion and release.
3. There are seven serotypes of botulinum neurotoxin, labeled A through G, with types A, B, E, and F being the most commonly associated with human disease.
4. Botulism can be contracted through ingestion of contaminated food, wound infections, or intestinal colonization in infants.
5. The primary treatment for botulism includes administration of antitoxins and supportive care such as mechanical ventilation.

Review Questions

• What mechanism does botulinum neurotoxin use to cause paralysis?
• What are the common routes of transmission for botulism?
• Which serotypes of botulinum neurotoxin are most commonly associated with human disease?

Related terms

Clostridium botulinum: Gram-positive, anaerobic bacterium that produces botulinum neurotoxin.

SNARE proteins: Proteins involved in mediating vesicle fusion during neurotransmitter release.

Antitoxin: A substance used to neutralize toxins in cases of poisoning or infection.