Which toxin types of Clostridium botulinum are associated with human botulism?

• A. Types C and D
• B. Types A, B, E, and F
• C. Type G
• D. Types B and C

Answer: (B)

Botulinum neurotoxin serotypes that cause disease in humans are A, B, E, and F. These are the serotypes repeatedly linked to human foodborne botulism and clinical illness around the world. Type E is especially noted in fish and marine environments, while types A and B are the most common culprits in many regions. Type F also causes human botulism, though less frequently. The other serotypes—C and D—are mainly associated with botulism in animals, not humans, and Type G has not been clearly linked to human disease. Therefore, the serotypes associated with human botulism are A, B, E, and F.