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

Small intestinal bacterial overgrowth (SIBO) refers to an abnormal increase in the number of bacteria in the small intestine and is observed in various diseases. SIBO can also develop after long-term use of proton pump inhibitors (drug-induced SIBO), bariatric surgery, gastrectomy, and other surgeries (postoperative SIBO). The aim of this narrative review is to summarize all of the published information on the treatment of SIBO in as much detail as possible and present it separately for each specific disease and intervention associated with SIBO. The most extensively studied drug for the treatment of SIBO is rifaximin. It eliminates SIBO in 63% of cases; however, most studies lack a control group. Small RCTs assessing the effects of this antibiotic on SIBO have reported conflicting results, and a meta-analysis showed no effect. A large RCT is required to verify the results of uncontrolled studies. Neomycin and norfloxacin showed efficacy in the treatment of SIBO in single RCTs, with elimination rates of 20 and 100%, respectively. Ciprofloxacin, rifamycin, metronidazole, and other antibiotics, as well as ursodeoxycholic acid, showed positive effects for the treatment of SIBO, but only in uncontrolled studies or in comparison with rifaximin or other drugs. The reported elimination rates were 54%, 67%, 79%, and 75%, respectively. Eradication therapy for Helicobacter pylori infection eliminated SIBO at a rate of approximately 70%. Probiotics have been tested for treatment of SIBO in various diseases. VSL#3 and Saccharomyces boulardii CNCM I-745 were effective in RCTs, with elimination rates of 58% and 80%, respectively. In conclusion, when selecting SIBO treatment regimens, those that have demonstrated the greatest efficacy for a specific concomitant disease should be preferred, despite the generally low level of evidence supporting these approaches in most cases.