Toxicity of cecal filtrates from guinea pigs with penicillin-associated colitis

Lethal enterocolitis was induced in guinea pigs by intramuscular injection of penicillin. The presence of filterable toxic substance in the cecal contents of penicillin-treated guinea pigs was demonstrated. The toxin was heat-labile and produced enterosorption activity in rabbit intestinal loops and morphologic changes in Y-1 adrenal cell cultures. The cecal filtrates were lethal for mice when injected intraperitoneally and lethal for guinea pigs when injected intraperitoneally or intracecally. Cecal filtrates from saline-treated guinea pigs were not lethal to experimental animals. Filtrates prepared from broth cultures of cecal contents from penicillin or saline-treated guinea pigs also showed the presence of a lethal toxic substance. The study demonstrated that bacteremia is minimal, nonspecific and probably a terminal event in penicillin-associated deaths in guinea pigs.