ANTIBIOTIC-ASSOCIATED DIARRHEA AND COLITIS

Pseudomembranous colitis has markedly increased in frequency since 1977, when Clostridium difficile was found to be its cause. Relapsing colitis has also become a common problem, but studies suggest that a nonpathogenic yeast, Saccharomyces boulardii, may terminate multiple relapses in about 50% of patients. This yeast also appears useful in the prevention of antibiotic-associated diarrhea. Studies on the mechanisms of action of toxins A and B, both of which play important roles in causing human disease, are yielding clinically useful information. Although we still lack a rapid and reliable diagnostic test, a polymerase chain reaction test to detect mRNA of toxins in stools of patients is promising. Metronidazole has become the preferred therapy for most patients with C. difficile-associated diarrheal syndromes.