Distinction between Clostridium botulinum type A strains associated with food-borne botulism and those with infant botulism in Japan in intraintestinal toxin production in infant mice and some other properties.

Two strains of Clostridium botulinum type A associated with food-borne botulism and six strains associated with infant botulism in Japan were compared in intraintestinal toxin production in infant mice, in vitro toxin and hemagglutinin production, molecular sizes of the toxins, and some other properties. The infant botulism-associated strains, producing M toxin (Mr 300 kDa) but no hemagglutinin, showed significantly lower 50% infective doses in infant mouse intestines. The antigenicities of the toxin differed between the two groups, while the biochemical properties of the cultures did not. Besides infant botulism-associated strains, this set of properties were found only in a strain isolated from honey of South American origin.