Cultural and physiological characteristics of Clostridium botulinum type G and the susceptibility of certain animals to its toxin

Abstract

Strain 89 of C. botulinum type G, isolated by Gimenez and Ciccarelli in 1969, was characterized culturally, biochemically, and toxigenically. It was motile, hemolytic, asaccharolytic, weakly proteolytic, lipase and lecithinase negative, and it produced acetic, isobutyric, butyric, and isovaleric acids in peptone-yeast extract-glucose broth. No spores were seen in smears from solid or liquid media. Very low levels of toxin were produced in regular broth cultures, but dialysis cultures yielded 30,000 mouse 50% mean lethal doses (LD50) per ml. Dogs and lambs were resistant to intragastric challenges of up to 75,000 mouse LD50 per kg of body weight. Rhesus monkeys, chickens, and guinea pigs were susceptible to enteral and parenteral challenge with the toxin. These species showed signs of botulism after challenge that were similar to, if not identical with, those observed in other studies with other botulinal toxin types. The lethal doses for monkeys were 33,000 and 120 mouse LD50 per kg, intragastrically and intravenously, respectively, for chickens, 3,125 and 1,200 to 2,600 mouse LD50 per kg, orally and subcutaneously, respectively; and for guinea pigs, 10,000 to 20,000 and 100 mouse LD50 per kg, intragastrically and intraperitoneally, respectively.