Infantile botulism caused by Clostridium butyricum type E toxin.

The case of a 9-month-old boy with infantile botulism caused by Clostridium butyricum type E toxin is reported. Because infantile botulism is rare in Japan, it was difficult to diagnose it at an early stage. Electrophysiologic findings were useful for the diagnosis, and were characterized by incremental responses (waxing) to short intervals and rapid repetitive nerve stimulation. A bioassay for botulism in mice indicated that the patient had botulism due to type E or F botulinum toxin. C. butyricum type E was isolated from his feces, confirming the diagnosis. This is the first known case of infantile botulism due to C. butyricum type E toxin in Japan.