Production of Enterotoxin by Vibrio vulnificus Isolates.

Weakly virulent isolates of Vibrio vulnificus that were lethal only to simultaneously iron-overloaded and immunosuppressed mice were tested for ability to cause fluid accumulation in the permanently ligated rabbit ileal loop. Unlike the highly virulent isolates, which caused septicemia and death in rabbits, these isolates caused significant fluid accumulation in the rabbit loops. Fluid accumulation was also observed when culture filtrates were tested, indicating the existence of an enterotoxin.

Oral Infectivity of Vibrio vulnificus in Suckling Mice.

Lethal doses of 11 clinical and environmental isolates of Vibrio vulnificus were determined in suckling mice after oral challenge. With one exception, isolates that were virulent to iron-overloaded adult mice after intraperitoneal inoculation were highly lethal to the infant mice (>50% lethality at 10 CFU/mouse). The virulent isolate that failed to kill infant mice at 10 CFU had lost its invasiveness.

Evidence That Clostridium perfringens Produces Only One Enterotoxin.

Thirteen Clostridium perfringens isolates classified as nonenterotoxigenic by radioimmunoassay (RIA) were tested for biological activity in rabbit ileal loops to determine whether these organisms produced enterotoxins serologically unrelated to the classical C. perfringens enterotoxin. None of these strains was active in the ileal loop assays.