Saccharomyces boulardii and gut bacteria during antibiotic treatment for early Lyme skin rash
Tests Saccharomyces boulardii on gut bacteria in adults taking amoxicillin for Lyme skin rash.
Key facts
- Who runs it
- Biocodex
- Where
- Ljubljana, SloveniaSee the siteAlso in 3 other countries, 17 sites
- Trial code
- Registry title
- Effect of Saccharomyces Boulardii CNCM I-745 on Gut Microbiota in Patients Undergoing Antibiotic Therapy (in the Context of Erythema Migrans (Early Skin Form of Lyme Borreliosis))
- Status
- Recruiting
- Phase
- Phase 4
- People taking part
- 120 people, planned
- Started
- 16 Jul 2025
- Expected to end
- Dec 2026
- Type of study
- Interventional, 2 groupsOne group gets a placebo (a dummy treatment), for comparison.
- Treatments tested
- Amoxicillin + Saccharomyces boulardii CNCM I-745
- Amoxicillin + Placebo
- Stool samples
- BSFS : Bristol Stool Form Scale
- GSRS : Gastrointestinal Symptom Rating Scale
- Record updated
- 27 August 2025
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with erythema migrans, the early skin form of Lyme disease, who are prescribed amoxicillin. It tests whether Saccharomyces boulardii CNCM I-745 changes their gut bacteria.
- Age
- 18 years and older.
- Sex
- All sexes can join.
- Disease stage
- Erythema migrans (early skin form of Lyme borreliosis), with antibiotic treatment prescribed: amoxicillin 1000 mg twice a day for 14 days.
- Earlier treatment
- No antibiotic treatment of the whole body in the 2 months before joining. No new prescription medicines in the 2 weeks before. No probiotics, laxatives or other products that change the gut in the 4 weeks before. No antifungals in the 14 days before.
- Biomarker or test result
- Women who can become pregnant need a negative urine pregnancy test before starting.
Main reasons for not taking part
- Allergy to the study treatments or to brewer's or baker's yeast.
- Long-term constipation (fewer than 3 bowel movements a week) or long-term or repeated diarrhoea, or past Clostridium difficile infection.
- Past gut surgery (except appendix or gallbladder removal more than one year ago) or active inflammatory gut disease.
- Weak immune system (for example organ transplant, cancer, chemotherapy, HIV), a central venous catheter, or severe liver or kidney problems.
- Breastfeeding, drug or alcohol abuse, or smoking more than 10 cigarettes per day.
The registry criteria, word for word
Show all 29 criteriaShow less
Who can take part
- Adult Patients, ≥18 years old
- Who are prescribed antibiotic therapy (as per medical routine practices, amoxicillin 1000 mg bid for 14 days) in the context of erythema migrans (early skin form of Lyme borreliosis)
- Able to comply with study requirements and to provide signed informed consent before any study procedure
- Has no condition that may interfere with the study assessments
- Able to fulfil in the diary stool log, according to the physician's opinion
- Regular defecation (frequency and stool consistency, with at least about three bowel movements a week)
- For women of childbearing potential:
- A negative urine pregnancy test immediately prior to starting the study treatment,
- Agreement to comply with approved methods of contraception during the whole study: unless they meet the criteria of post-menopausal, i.e. 12 months of spontaneous amenorrhea, women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, including women whose career, lifestyle, or sexual orientation precludes intercourse with a male partner, should use one or more acceptable methods of contraception that should be maintained throughout the study
Who cannot take part
- Contraindication and special warning to the study drugs according to the SmPCs,
- Prior gastrointestinal surgery (apart from appendectomy or cholecystectomy performed at least more than one year ago),
- Systemic antibacterial therapy during the 2 months prior to study enrollment,
- New prescription medications during the 2 weeks prior to study enrollment,
- Use of any drug or product that alters gut microbiota or function, such as probiotics, laxatives, antiemetics, cisapride, antisecretory or adsorbent treatments (racecadotril, smectite, activated charcoal), opiates such as loperamide, atropine and other cholinergic agents, 4 weeks prior to study enrollment and during the study,
- Intake of antifungals within 14 days prior to study enrollment,
- Substantial changes in eating habits within 30 days prior to receiving the first dose of IMP product, and during the study as assessed by the Investigator,
- History or presence of drug or alcohol abuse,
- Patients enrolled in another interventional clinical trial where they received an investigation treatment within the past 30 days,
- History of hypersensitivity to the study treatments (active substance or excipients), brewer's or baker's yeast,
- History of chronic constipation with passage of fewer than 3 spontaneous bowel movements per week on average,
- History of chronic or recurrent diarrhoea with spontaneous unformed bowel movements equivalent to or more often than 3 times daily,
- History of Clostridium difficile infection,
- Active gastrointestinal inflammatory disease,
- Known chronic or recurrent systemic disorder that may interfere with the study drug evaluation,
- Immunocompromised (organtransplants, leukaemia, malignant tumours, radiotherapy, chemotherapy,prolonged high dose cortisone treatment, immunosuppressant treament) or critically ill patients (such as autoimmune disease, HIV,…), patients with a central venous catheter,
- Severe hepatic or renal impairment,
- Any condition or personal circumstance that, in the opinion of the investigator, rendered the subject unlikely or unable to comply with the full study protocol
- Heavy smoker (more than 10 cigarettes per day),
- Breast-feeding woman,
Where in Slovenia
Also in 3 other countries, 17 sites
- University Medical Center LjubljanaLjubljana, SloveniaNo longer taking part
About the trial
What the trial wants to find out
The aim of this study is to assess the effect of Saccharomyces boulardii CNCM I-745 on gut microbiota in patients undergoing antibiotic therapy (in the context of erythema migrans (early skin form of Lyme borreliosis)).
The 2 groups in the trial
- Amoxicillin + Saccharomyces boulardii CNCM I-745Treatment being tested
The patients will received oral Amoxicillin (1000 mg capsules bid) for 14 days and oral Saccharomyces boulardii CNCM I-745 (®) 250 mg x 2 capsules twice a day for 21 days.
Treatment: Amoxicillin + Saccharomyces boulardii CNCM I-745, Stool samples, BSFS : Bristol Stool Form Scale, and GSRS : Gastrointestinal Symptom Rating Scale
- Amoxicillin + PlaceboPlacebo, for comparison
The patients will received oral Amoxicillin (1000 mg capsules bid) for 14 days + oral Placebo capsules for 21 days.
Treatment: Amoxicillin + Placebo, Stool samples, BSFS : Bristol Stool Form Scale, and GSRS : Gastrointestinal Symptom Rating Scale
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
- Official title
- Effect of Saccharomyces Boulardii CNCM I-745 on Gut Microbiota in Patients Undergoing Antibiotic Therapy (in the Context of Erythema Migrans (Early Skin Form of Lyme Borreliosis))
- Plain-language title
- Saccharomyces boulardii and gut bacteria during antibiotic treatment for early Lyme skin rashGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 14 November 2026.
- Record updated
- 27 August 2025