Microbiology, Epidemiology, and Pathogenesis

Botulism is a paralytic disease caused by neurotoxins elaborated by Clostridium botulinum, an anaerobic spore-forming gram-positive bacterium, as well as a few other toxigenic Clostridium spp.

• Botulism is caused by the toxin’s inhibition of acetylcholine release at the neuromuscular junction through an enzymatic mechanism.
  • C. botulinum toxin types A, B, E, and (rarely) F cause human disease, with toxin type A causing the most severe syndrome.
  • Toxin type E is associated with foods of aquatic origin.
• Transmission is usually due to consumption of foods contaminated with botulinum toxin, but contamination of wounds with spores also can result in disease.
  • Most U.S. food-borne cases (average, 23 cases per year) are associated with home-canned food.
  • Infant botulism results from toxigenic clostridial colonization of the intestine of children <1 year of age and is the most common form of the disease in the United States, with ~80–100 cases reported annually.
• Toxin is heat-labile, and spores are heat-resistant; these properties underscore the importance of properly heating foods.
• Botulinum toxin is among the most toxic substances known and thus is of concern as a potential weapon of bioterrorism.