Colitis induced by Clostridium difficile.

Clostridium difficile has been implicated as the major cause of antibiotic-associated pseudomembranous colitis. The current laboratory diagnostic test of choice is a tissue culture assay that demonstrates the presence of a cytopathic toxin neutralized by antitoxin to Clostridium sordellii. This toxin was found in stools from 42 of 43 patients with antibiotic-associated pseudomembranous colitis and in stools from 12 of 78 patients with antibiotic-associated diarrhea. Specimens from patients with gastrointestinal conditions unrelated to administration of antibiotics and those from healthy controls were uniformly negative. Neutralization of toxin by antitoxin to C. sordellii appears to represent antigenic cross-reactivity, since broth cultures of C. difficile also contain a cytopathic toxin neutralized by this antitoxin. Strains of C. difficile are susceptible to vancomycin, and the initial clinical experience with oral administration of this agent shows promising results.