Laboratory findings in four cases of adult botulism suggest colonization of the intestinal tract.

There was laboratory evidence of intestinal colonization in four cases of adult botulism confirmed by the Centers for Disease Control. No performed toxin was detected in available foods, but Clostridium botulinum was isolated from foods in two instances. Botulinal toxin was detected in the sera of all four patients, in one case at 47 days after ingestion of suspected food. C. botulinum was demonstrated in the stool of all four patients and persisted for 119 days after the onset of illness in one patient. Two patients had surgical alterations of the gastrointestinal tract, which may have promoted the colonization. The apparent lack of ingestion of performed toxin in these cases and the persistence of botulinal toxin or C. botulinum, or both, for long periods in three of the patients suggest that colonization of the intestinal tract occurred.