Treatment of Small Intestinal Bacterial Overgrowth (SIBO) in Gastrointestinal, Hepatic, Endocrine, Neurological, and Postoperative Diseases: A Comprehensive Narrative Review

Small Intestinal Bacterial Overgrowth (SIBO) is characterized by an abnormal increase in bacterial populations within the small intestine. While historically diagnosed via bacterial culture, modern clinical practice relies on breath tests that detect hydrogen and methane gases produced by these bacteria after carbohydrate ingestion. SIBO is not merely a local digestive issue; it is increasingly recognized as a systemic factor in conditions ranging from liver disease and metabolic disorders to neurological conditions like Parkinson’s disease.

Treatment strategies vary significantly depending on the underlying cause, such as anatomical changes from surgery, motility disorders, or the use of proton pump inhibitors. Rifaximin, a non-absorbable antibiotic, is the most widely studied intervention. While meta-analyses suggest a 63% eradication rate, its performance in placebo-controlled trials has been inconsistent, often showing no significant superiority over placebo in small-scale studies.

Other antibiotics, including neomycin, norfloxacin, ciprofloxacin, and metronidazole, have demonstrated efficacy in specific contexts. However, these are often supported by uncontrolled studies or small trials. Probiotics, such as VSL#3 and Saccharomyces boulardii, have also shown promise in randomized trials, suggesting that modulating the gut microbiome may be a viable strategy for some patient populations.

Because SIBO often presents as a secondary complication of other diseases, the authors emphasize that there is no one-size-fits-all treatment. Clinicians should tailor therapy to the patient's specific concomitant disease. For instance, prokinetic agents may be necessary for patients with motility-related SIBO, whereas antibiotic therapy alone may be insufficient in cases of anatomical disruption. The high rate of recurrence—often linked to the persistence of the underlying pathology—highlights the need for long-term management strategies rather than simple, one-time eradication attempts.