The effectiveness of rotating versus single course antibiotics for small intestinal bacterial overgrowth

United European Gastroenterol J. 2021 Jul;9(6):645-654. doi: 10.1002/ueg2.12116. Epub 2021 Jul 9.


Background: Small intestinal bacterial overgrowth treatment is usually based on antibiotics with no guidelines available.

Objective: This study aimed to investigate the efficacy of different antibiotics to treat small intestinal bacterial overgrowth.

Methods: Consecutive patients referred to our tertiary center and diagnosed with intestinal bacterial overgrowth were retrospectively included. Patients were diagnosed using a 75 g glucose breath test. Patients were treated either with a single antibiotic (quinolone or azole) or rotating antibiotics (quinolone and azole, one after the other) for 10 consecutive days per month for 3 months. A negative glucose breath test after antibiotic treatment was considered as remission. Quality of life (GIQLI) and gastrointestinal severity (IBS-SSS) were assessed before and after antibiotic treatment. Symptomatic evaluation was realized in simple blind of glucose breath test result: patients were unaware of their results.

Results: Between August 2005 and February 2020, 223 patients were included in the analysis (female 79.8%, mean age 50.2 ± 15.7 years). Remission was observed in 119 patients (53.4%) after one course of antibiotics and was more frequent in patients receiving rotating antibiotics than in patients receiving a single antibiotic (70.0% vs. 50.8%, p = 0.050). Remission was associated with a significant improvement in quality of life (p = 0.035) and in bloating (p = 0.004).

Conclusion: In this study, the treatment of small intestinal bacterial overgrowth using rotating antibiotics was more effective than treatment using a single course of antibiotic. Remission was associated with improvement in both quality of life and bloating.

Keywords: SIBO; antibiotics; bacterial overgrowth; breath tests; ciprofloxacin; metronidazole; norfloxacin; quality of life; remission; rotating antibiotics; single course; small intestinal bacterial overgrowth.

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / therapeutic use*
  • Azoles / therapeutic use*
  • Bacterial Infections / diagnosis
  • Bacterial Infections / drug therapy*
  • Breath Tests
  • Drug Administration Schedule
  • Female
  • Humans
  • Intestine, Small / microbiology*
  • Male
  • Middle Aged
  • Quality of Life
  • Quinolones / therapeutic use*
  • Retrospective Studies


  • Anti-Bacterial Agents
  • Azoles
  • Quinolones