Which statement about Clostridium botulinum is true?

Which statement about Clostridium botulinum is true?

• A. Infant botulism is the most common clinical form.
• B. Pathogenicity is related to a potent exotoxin destroying host tissue.
• C. Oval spores are located centrally.
• D. Of the seven toxogenic types, types C and D are associated with human botulism.

Answer: (A)

Infant botulism being the most common clinical form reflects how the disease arises when botulinum spores are ingested and can colonize the immature gut, producing toxin there. In infants under one year, the normal gut microbiota isn’t fully established, allowing spores—often acquired from environmental sources like honey—to germinate and generate botulinum toxin in the intestine. The toxin then enters the bloodstream and blocks acetylcholine release at neuromuscular junctions, causing the characteristic flaccid paralysis, without causing direct tissue destruction. This mode of disease is more frequently seen in this age group than other forms because adults typically have gut flora that suppresses spore colonization and because exposures leading to toxin ingestion are less common in infants. The other statements don’t fit because the disease mechanism is neurotoxin-mediated interference with neurotransmitter release rather than destruction of host tissue, so it doesn’t destroy tissue directly. Spores of Clostridium botulinum are usually subterminal (near the end of the spore) rather than centrally located. And among the seven toxin types, humans are most commonly affected by types A, B, and E; types C and D more often cause botulism in animals.

Infant botulism being the most common clinical form reflects how the disease arises when botulinum spores are ingested and can colonize the immature gut, producing toxin there. In infants under one year, the normal gut microbiota isn’t fully established, allowing spores—often acquired from environmental sources like honey—to germinate and generate botulinum toxin in the intestine. The toxin then enters the bloodstream and blocks acetylcholine release at neuromuscular junctions, causing the characteristic flaccid paralysis, without causing direct tissue destruction. This mode of disease is more frequently seen in this age group than other forms because adults typically have gut flora that suppresses spore colonization and because exposures leading to toxin ingestion are less common in infants.

The other statements don’t fit because the disease mechanism is neurotoxin-mediated interference with neurotransmitter release rather than destruction of host tissue, so it doesn’t destroy tissue directly. Spores of Clostridium botulinum are usually subterminal (near the end of the spore) rather than centrally located. And among the seven toxin types, humans are most commonly affected by types A, B, and E; types C and D more often cause botulism in animals.