Francesco Manguso¹
¹Department of Gastroenterology, Ospedale Cardarelli di Napoli, Naples, Italy
ABSTRACT
Background & Aims: Small intestinal bacterial overgrowth (SIBO) frequently relapses after antibiotic treatment. This prospective observational study evaluated the efficacy of SIBOVAL, either as monotherapy or in combination with rifaximin, compared with rifaximin monotherapy.
Methods: Adult patients with confirmed SIBO were assigned to rifaximin plus SIBOVAL (n=62), SIBOVAL monotherapy (n=47), or rifaximin monotherapy (historical reference group). Eradication was assessed at 60 days and recurrence at 9 months.
Results: Eradication rates at 60 days were 81.0% for rifaximin + SIBOVAL, 59.3% for SIBOVAL alone, and 72.9% for rifaximin alone. Recurrence rates at 9 months were 16.3%, 18.3%, and 43.7%, respectively.
Conclusions: Both SIBOVAL monotherapy and its combination with rifaximin achieved better long-term outcomes than rifaximin monotherapy, particularly in preventing relapse. SIBOVAL appears to be a useful adjunct or maintenance option in SIBO management.
Keywords: Small intestinal bacterial overgrowth, SIBOVAL, rifaximin, probiotics, recurrence.
INTRODUCTION
Small intestinal bacterial overgrowth (SIBO) is characterized by excessive bacterial proliferation in the small intestine, leading to symptoms such as bloating, abdominal discomfort, and altered bowel habits. The condition is often treated with non-absorbable antibiotics, mainly rifaximin, but recurrence after treatment is common [1].
Probiotic supplementation may contribute to restoring intestinal eubiosis and reducing recurrence rates [2]. SIBOVAL is a probiotic formulation containing both tindalized and viable bacterial strains, designed for adjuvant and maintenance therapy. The present study evaluates the efficacy of SIBOVAL, either alone or in combination with rifaximin, compared with rifaximin monotherapy.
MATERIALS AND METHODS
Study Design and Population:
This was a prospective, single-center, observational study conducted at the Ospedale Cardarelli di Napoli (Italy) between April 2024 and March 2025.
Inclusion criteria: Adults aged 18–75 years with confirmed SIBO, diagnosed by a hydrogen–lactulose breath test.
Exclusion criteria: Prior probiotic therapy within 4 weeks, ongoing antibiotic use, inflammatory bowel disease, or significant hepatic/renal impairment.
Treatment Groups:
Group A: Rifaximin 550 mg three times daily for 14 days plus SIBOVAL 1 capsule daily for 9 months (n=62; 39 females, 23 males).
Group B: SIBOVAL 1 capsule daily for 9 months as monotherapy (n=47; 32 females, 15 males).
Group C: Rifaximin monotherapy (historical data from Redondo-Cuevas et al., 2024) [5].
Outcome Measures:
Primary endpoints:
1. Eradication (60 days): Defined as a negative breath test and complete resolution of SIBO-related symptoms.
2. Recurrence (9 months): Defined as symptom relapse and/or positive breath test.
Statistical Analysis:
Descriptive and comparative analyses were performed among groups. Data for rifaximin monotherapy were derived from published literature [5].
RESULTS
Demographic Characteristics:
Group | Females (n/%) | Males (n/%) | Age (years)
Rifaximin + SIBOVAL | 39 (62.9%) | 23 (37.1%) | 18–75
SIBOVAL Monotherapy | 32 (68.1%) | 15 (31.9%) | 18–75
Rifaximin Monotherapy* | n/a | n/a | n/a
*Data from Redondo-Cuevas et al., 2024 [5].
Efficacy and Recurrence:
Group | Eradication (60 days, %) | Recurrence (9 months, %)
Rifaximin + SIBOVAL | 81.0 | 16.3
SIBOVAL Monotherapy | 59.3 | 18.3
Rifaximin Monotherapy* | 72.9 | 43.7
*Reference data from Redondo-Cuevas et al., 2024 [5].
DISCUSSION
Combination therapy with SIBOVAL and rifaximin demonstrated superior eradication and significantly lower recurrence compared with rifaximin alone, suggesting a synergistic effect between antibiotic and probiotic interventions. The efficacy of SIBOVAL monotherapy—although lower in eradication—was associated with a notably reduced recurrence rate, supporting its role as a maintenance option or as an alternative for patients intolerant to antibiotics.
These findings reinforce the hypothesis that modulation of the intestinal microbiota contributes to sustained remission in SIBO [3,4]. Limitations of this study include its observational design, modest sample size, and single-center nature. Randomized controlled trials are required to confirm these preliminary results.
CONCLUSIONS
SIBOVAL improves both efficacy and maintenance of remission in SIBO, either as an adjunct to rifaximin or as monotherapy. Its incorporation into therapeutic regimens may enhance outcomes and reduce antibiotic dependence.
REFERENCES
1. Pimentel M, Saad RJ, Long MD, Rao SSC. ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth. Am J Gastroenterol. 2020;115(2):165–178.
2. Ghoshal UC, Ghoshal U, Das K, et al. Small intestinal bacterial overgrowth and irritable bowel syndrome: bridging the organic–functional divide. Gut Liver. 2017;11(2):196–208.
3. Ford AC, Quigley EMM, Lacy BE, et al. Efficacy of probiotics in irritable bowel syndrome and small intestinal bacterial overgrowth: a systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2014;12(6):925–935.
4. Zhong C, Qu C, Wang B, Liang S, Zeng B. Probiotics for the prevention and treatment of small intestinal bacterial overgrowth: a systematic review and meta-analysis of randomized controlled trials. J Gastroenterol Hepatol. 2017;32(1):19–28.
5. Redondo-Cuevas L, Belloch L, Martín-Carbonell V, et al. Do herbal supplements and probiotics complement antibiotics and diet in the management of small intestinal bacterial overgrowth (SIBO)? A randomized clinical trial. Nutrients. 2024;16(7):1083.