Small intestinal bacterial overgrowth is a condition in which the small bowel is colonised by excessive bacteria. A tertiary hospital guidelines recommend three cycles of fortnightly Rifaximin and Biokult.

This retrospective study aims to review the indications and outcomes of Rifaximin in gut decontamination. Patients were identified through electronic patient records over a five-year period. Data was collected from clinical notes and letters.

74 patients identified with positive documentation to initiate ‘gut decontamination’ and received either Rifaximin [8%], Rifaximin with Biokult [88%] and Rifaximin with over-the counter probiotics [4%]. Background included, short gut [20%], genetic disorders [8%], irritable bowel syndrome (IBS) [43%] and neurodisability [27%]. Analysis of symptoms based on background; Short gut: Abdominal pain [15], Loose stools [9], Flatus [5], Nausea/Vomiting [4], Dystonia [1], Constipation [1], Feed intolerance [1]; Neurodisability: Abdominal pain [15], Loose stools [11], Flatus [5], Dystonia [4], Constipation [3], Nausea/vomiting [2], Feed intolerance [2], Offensive stools [1]; Genetic: Abdominal pain [8], Loose stools [4], Flatus [3], Dystonia [2], Constipation [2], Nausea/Vomiting [1], Feed intolerance [1]; IBS: Abdominal Pain [35], Loose stools [17], Flatus [10], Constipation [5], Nausea/Vomiting [3], Feed intolerance [3]. Treatment response based on follow up physician global assessment. No improvement [36%], partial response [26%], full response [26%], Unknown [12%]. Responses for background diagnoses; Short gut: full response [4], partial [9], no [2]; Neurodisability: full response [7], partial [5], no [6], unknown [2]; Genetic: full response [2], no [3], unknown [1]; IBS: full response [6], partial [5], no [16], unknown [6].

40%- 60% of neurodisability or genetic condition patients had symptomatic improvement (either full or partial) post treatment. However, only 33% of IBS patients responded (either full or partial). Given these results and Rifaximin cost; investigations (plasma d-lactate and hydrogen breath test) should be done prior to therapy to avoid over-treatment.

References

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2. Grace E, Shaw C, Whelan K, Andreyev HJN. Review article: small intestinal bacterial overgrowth – prevalence, clinical features, current and developing diagnostic tests, and treatment. Aliment Pharmacol Ther, 2013;38:674–688. https://doi.org/10.1111/apt.12456

3. Koo HL, DuPont HL. Rifaximin: a unique gastrointestinal-selective antibiotic for enteric diseases. Curr Opin Gastroenterol. 2010 Jan;26(1):17–25. doi: 10.1097/MOG.0b013e328333dc8d. PMID: 19881343; PMCID: PMC4737517.