NCT07426705

Effect of Multispecies Probiotic Supplementation on the Efficacy of Rifaximin α Therapy in Patients With Small Intestinal Bacterial Overgrowth (SIBO): a Randomized Placebo-controlled Trial

Effect of Enterococcus Faecium and Bacillus Subtilis-Containing Multispecies Probiotic Supplementation on the Therapeutic Efficacy of Rifaximin α in Patients With Small Intestinal Bacterial Overgrowth (SIBO): a Prospective, Randomized, Placebo-controlled Trial

• Status: Not Yet Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 100 (estimated)
• Sponsor: Państwowy Instytut Medyczny Ministerstwa Spraw Wewnętrznych i Administracji · Other Government
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

Small intestinal bacterial overgrowth (SIBO) is a common condition associated with gastrointestinal symptoms such as bloating, abdominal pain, diarrhea, and constipation, particularly in patients with irritable bowel syndrome. Antibiotic therapy with rifaximin is commonly used, but relapse rates remain high. This randomized, placebo-controlled clinical trial aims to evaluate whether supplementation with a multispecies probiotic containing Enterococcus faecium and Bacillus subtilis improves the effectiveness of rifaximin therapy in adult patients with SIBO. Participants will be randomly assigned to receive either rifaximin plus the probiotic or rifaximin plus placebo. Clinical assessments will include hydrogen breath testing and evaluation of gastrointestinal symptoms using standardized questionnaires at baseline and during follow-up visits. The study is being conducted at a single academic medical center in Poland and is sponsored by Państwowy Instytut Medyczny MSWiA. The probiotic and rifaximin are provided by Urgo. The results of this study may help determine whether probiotic supplementation can improve treatment outcomes and reduce recurrence of SIBO.

Conditions

• Small Intestinal Bacterial Overgrowth Syndrome (SIBO)
• IBS

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Probiotic preparation	Oral probiotic preparation administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The product contains a defined combination of bacterial strains and is intended to support restoration of gut microbiota and reduce recurrence of SIBO.
OTHER	Placebo	Matching oral placebo capsule administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The placebo is identical in appearance, taste, and packaging to the probiotic product but contains no live microorganisms.
DRUG	Rifaximin (drug)	Rifaximin is administered to all participants as background standard therapy for SIBO at a dose of 1600 mg per day orally for 14 days. The randomized comparison concerns adjunctive probiotic versus placebo.

Timeline

• Start date: 2026-02-15
• Primary completion: 2027-07-15
• Completion: 2027-07-15
• First posted: 2026-02-23
• Last updated: 2026-02-23