A randomized double-blind study was carried out in patients with unresolving
antibiotic-associated colitis due to Clostridium difficile, to compare the effect of
bacitracin (80,000 U/day) with
vancomycin (500 mg/day) on the resolution of symptoms, clearance of organism, and prevention of relapse. Forty-two patients with
colitis, 9 of whom had a pseudomembrane, were randomized, 21 patients to each treatment group. The two groups were comparable in age, disease severity, and
antibiotic exposure. For a 50% reduction in stool frequency the mean times (+/- SE) were 4.1 +/- 0.4 days for
bacitracin and 4.2 +/- 0.4 days for
vancomycin. Sixteen patients (76%) had symptom resolution after 7 days of treatment with
bacitracin, compared with 18 patients (86%) given
vancomycin. Patients who failed to respond were crossed over (blind) to the alternative
antibiotic, but tended to be refractory to the alternative medication as well.
Vancomycin-treated patients had negative toxin (83% vs. 53%, p = 0.04) and negative stool cultures (81% vs. 52%, p = 0.02) more frequently than did those patients given
bacitracin. Similar numbers of patients in each group had symptomatic relapse during 1 mo of follow-up, but most of them relapsed yet again after blinded crossover
therapy. Although
bacitracin was significantly less effective than
vancomycin in clearing C. difficile from the stools, both were of similar value in the control of symptoms in a group of patients with predominantly nonpseudomembranous
colitis. In view of its low cost,
bacitracin is a reasonable first-line alternative to
vancomycin in the treatment of
antibiotic-associated colitis.