[Report of "lethal factor" synthetized by Bacillus cereus (author's transl)]

Abstract

Bacillus cereus growing in nutrition broth produces during logarithmic growth and in stationary phase a lethal factor extremely toxic for rodents. This toxin is only produced in the presence of oxygen and depends on bacterial replication. The highest titers of toxin are obtained using bacteria in a concentration of 10(7) to 10(9) per ml of nutrition broth. During regression phase of Bacillus cereus the titer of toxin declines to zero. Toxicity of the lethal factor becomes not altered in an alcaline or acidic medium. Temperatures exceeding 65 degrees C inactivate the toxin indicating its thermolability. Oral and rectal dispension of large quantities of the lethal factor does not induce toxic symptoms in rodents. However, when applicating toxin containing cultural filtrate of Bacillus cereus as an i.v., i.p., i.n. or s.c. injection it becomes highly toxic for mice, rats, hamsters, guinea pigs and rabbits. All animals injected by the different ways parenterally died.