Production of Enterotoxin by Vibrio vulnificus Isolates

Abstract

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. Enterotoxin activity did not correlate with the hemolysin or protease activities. Only one of three enterotoxigenic isolates caused diarrhea when administered to temporarily ligated rabbit ileal loops, suggesting involvement of some other pathogenic determinant(s) such as colonization.