Antibiotic treatment of small bowel bacterial overgrowth in patients with Crohn's disease

Background: Small bowel bacterial overgrowth is common in Crohn's disease but its treatment is not clearly defined. Metronidazole and ciprofloxacin are effective antibiotics in active Crohn's disease. Aim: To investigate the efficacy of metronidazole and ciprofloxacin in the treatment of bacterial overgrowth in patients with Crohn's disease. Patients and methods: We performed the lactulose breath test in 145 consecutive patients affected by Crohn's disease. Patients positive to the lactulose breath test underwent a glucose breath test to confirm the overgrowth. These patients were randomized in two treatment groups: metronidazole 250 mg t.d.s. (Group A) and ciprofloxacin 500 mg b.d. (Group B), both orally for 10 days. The glucose breath test was repeated at the end of treatment. The clinical outcome after therapy was also recorded. Results: Bacterial overgrowth was present in 29 patients (20%). Breath test normalization occurred in 13 out of 15 patients treated by metronidazole and in all 14 patients treated by ciprofloxacin (P = ns). In both groups antibiotic treatment induced an improvement of intestinal symptoms: bloating (Group A 85% and Group B 83%), stool softness (44% and 50%), and abdominal pain (50% and 43%). Conclusions: Small bowel bacterial overgrowth is a frequent condition in Crohn's disease which can be effectively treated by metronidazole or ciprofloxacin.