Small intestinal bacterial overgrowth is common after gastrectomy but with little impact on nutritional status.

Background: Available evidence assessing the impact of small intestinal bacterial overgrowth (SIBO) following gastrectomy is limited.

Objectives: To evaluate the prevalence of SIBO after gastrectomy and its association with malnutrition. To describe the antibiotic treatment required to correct it and if nutritional status improves.

Material And Methods: A prospective cohort study was performed at the Agencia Sanitaria Costa del Sol (Costa del Sol Health Agency) from 2012 to 2015. A hydrogen-methane breath test with oral glucose overload was performed. Demographic variables and nutritional parameters were collected at baseline and one month after effective treatment of SIBO. The antibiotic regimens and the number of treatment lines used were assessed.

Results: Sixty gastrectomy patients were analysed, 58.3% of which were male. A sub-analysis of the curve was performed at 45min to minimise possible false positives, and SIBO was identified in 61.6% of cases. SIBO patients tended to have a lower BMI, although this trend was not statistically significant. After treatment with rifaximin, 94.6% of patients were still positive for SIBO, which fell to 85.7% after metronidazole. The rate of total antibiotic treatment failure was 67.6%. No statistically significant changes were found in nutritional parameters after treatment.

Conclusions: SIBO was identified in 61.6% of patients after gastrectomy. No correlation was found with any malnutrition parameter. Rifaximin and metronidazole were found to be largely ineffective in eradicating SIBO. When treatment was effective, the impact on malnutrition was negligible and may have been associated with other factors.