Study of Small Intestinal Bacterial Overgrowth in a Cohort of Patients with Abdominal Symptoms Who Underwent Bariatric Surgery

Obes Surg. 2020 Jun;30(6):2331-2337. doi: 10.1007/s11695-020-04477-5.


Introduction: Small intestinal bacterial overgrowth (SIBO) is a common complication of bariatric surgery. Digestive decontamination treatments with oral antibiotic therapy vary and are not codified. This retrospective study was conducted to analyse the characteristics of bariatric surgery patients who underwent a glucose breath test (GBT) and to analyse the effectiveness of the antibiotic decontamination therapy.

Materials and methods: A total of 101 operated patients (Roux-en-Y bypass (RYB), omega bypass (ΩB) and sleeve gastrectomy (SG)) who underwent a GBT (75 g/250 mL) were included. Anthropometric data, symptoms of SIBO, type of surgery, use of proton pump inhibitors (PPIs) and antibiotic therapy were analysed. The effectiveness of the antibiotic treatment, defined by improvement of the symptoms, was evaluated during the follow-up.

Results: Of the 85 women and 16 men included (48.5 ± 3.6 years old), 63 underwent RYB, 31 underwent ΩB and 7 underwent SG. The GBT was positive in 83% of the patients. A positive test was associated with age (p < 0.001), female sex (p < 0.01) and PPI use (p < 0.01), but there was no significant difference according to the type of surgery. Sixty-one percent of patients treated with gentamicin/metronidazole sequential antibiotic therapy and 58% of patients treated with metronidazole alone achieved treatment efficacy (with no significant difference in efficacy between these treatments).

Conclusion: SIBO should be systematically considered in the context of abdominal symptoms in bariatric surgery patients, regardless the type of surgery, particularly in patients who are older or female and after PPI treatment. Digestive decontamination appears to be similar between gentamycin/metronidazole and metronidazole treatments.

Keywords: Antibiotic therapy; Bariatric surgery; Glucose breath test; Obesity; Small intestinal bacterial overgrowth (SIBO).

MeSH terms

  • Adult
  • Anti-Bacterial Agents / therapeutic use
  • Bariatric Surgery*
  • Female
  • Gastrectomy
  • Humans
  • Male
  • Middle Aged
  • Obesity, Morbid* / surgery
  • Retrospective Studies


  • Anti-Bacterial Agents