Diarrhea we can treat: antibiotic-associated colitis

C. difficile, a gram-positive anaerobic bacillus, has emerged in the past five years as a common cause of hospital-acquired diarrhea. The organism usually gains entry to the host during or after antibiotic treatment, which presumably alters the normal barrier function of the colonic microflora. The organism produces a cytotoxin that can be identified in stool samples by its ability to alter the cellular morphology of tissue culture cells. Infection with C. difficile produces a spectrum of diseases ranging from mild diarrhea to fulminating colitis. An important bedside clue is the presence of pseudomembranes in the rectum or sigmoid at proctosigmoidoscopy. The disease may also occur in patients with chronic inflammatory bowel disease where it may be confused with a relapse of the underlying disease. Treatment with vancomycin is effective, but 10% to 15% of patients may experience relapse. The major mode of transmission appears to be environmental acquisition rather than person-to-person spread.