Antibiotics are effective in the treatment of bacterial overgrowth-related diarrhea.

This cross-over, randomized controlled trial evaluates the efficacy of antibiotic therapy in the treatment of chronic diarrhea secondary to bacterial overgrowth. Ten patients with a mean age of 62 yr (range 27-83), female to male ratio 1.5:1, and 10-yr mean duration of diarrhea comprise the study group. All patients had conditions which predisposed to bacterial overgrowth: jejunal diverticulosis, partial gastrectomy with vagotomy, scleroderma, idiopathic intestinal pseudoobstruction, duodenopancreatectomy, and diabetic autonomic neuropathy. They had a positive glucose ingestion hydrogen (H 2 ) breath test at inclusion. Study subjects underwent the following five 7-day treatment periods: no treatment (control), followed by placebo, then, in randomized order, norfloxacin (800 mg/day), amoxicillin clavulanic acid (1500 mg/day), and Saccharomyces Boulardii, a probiotic with purported beneficial effect in overgrowth. The authors noted a significant (p < 0.01) decrease in stool frequency in both antibiotic treatment groups. Expired H 2 decreased in some patients of each group. There was comparatively no change in the mean daily number of stools in the placebo (3.9 ± 0.6) and S. boulardii treatment periods (3.8 ± 0.5, p = 0.15). Based on these results, the authors concluded that the antibiotics norfloxacin and amoxicillin-clavulanic acid are effective in the treatment of bacterial-overgrowth related diarrhea.