Concerning toxic byproducts of bacillus botulinus

Attempting to shorten the incubation period of botulinus toxin by injecting gradually increasing amounts of toxin into mice, one of us (Orr) has observed early that when the amount of culture filtrate injected reach 0.5 c.c. animals frequently died within a few minutes after injection. Further study of the nature of this intoxication has brought out that when B. botulinus is grown on suitable medium there are produced, in addition to the specific toxin, other poisonous products. If such a culture is filtered through a Berkfeld candle and the filtrate treated with alcohol these secondary toxic products remain in solution. The alcoholic extract equivalent to 0.5 c.c. of the original filtrate is fatal when injected intraperitoneally into mice of 17-22 grams.

The first symptoms are noted immediately after injection and consist of restlessness and marked contraction of the abdominal muscles. Within a minute or two the animal shows increased response to external stimuli especially to sharp sound. Shortly the animal becomes prostrated. The increased excitability persists a few minutes longer, the respiration increases in depth and decreases in frequency, and may become as infrequent as 5 inspirations a minute. The animal goes into coma interrupted by sharp convulsive seizures with contraction of the extensor muscles throughout the body. Death occurs in 5 to 15 minutes after the injection and during one of these convulsive seizures. If less than a lethal dose is injected the animal may exhibit all the symptoms described above but will recover completely in 2 to 4 hours.

The toxic substances responsible for these acute symptoms are quite distinct from the specific botulinus toxin and are not neutralized by the specific antitoxin. Besides we obtained similar products from the cultures of “atoxic” strains of B. botulinus, as well as from those of B. sporogenes, B. tetani and B. proteus when these organisms were grown on medium composed of minced meat broth. 1