Actively Recruiting
Oxalobacter Formigenes Colonization in Calcium Oxalate Kidney Stone Formers
Led by University of Alabama at Birmingham · Updated on 2026-05-28
40
Participants Needed
2
Research Sites
52 weeks
Total Duration
On this page
Sponsors
U
University of Alabama at Birmingham
Lead Sponsor
U
University of Texas Southwestern Medical Center
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are investigating whether colonization with the gut bacteria Oxalobacter formigenes can reduce urinary oxalate levels in adults with a history of calcium oxalate kidney stones who are not currently colonized with this bacteria. The study aims to better understand how this bacterial colonization affects oxalate excretion and kidney stone formation. Participants will follow fixed diets with controlled amounts of oxalate to assess these effects. The study includes several phases: screening and pre-colonization, colonization and post-colonization, and a follow-up phase. During pre-colonization, participants consume low and moderately high oxalate diets for 4 days each, collecting urine, blood, and stool samples. After that, they ingest a live preparation of Oxalobacter formigenes to induce colonization, which is confirmed by stool testing. Post-colonization, participants repeat the same diet and sample collection process. Follow-up visits occur every 6 months for up to 4 years to monitor colonization sustainability and collect additional samples. Throughout the study, participants provide multiple 24-hour urine collections, blood samples, and stool samples to measure urinary oxalate and confirm bacterial colonization. Researchers will evaluate changes in urinary oxalate excretion two months after colonization and the long-term maintenance of colonization over four years. Participants are also monitored for diet adherence and complete questionnaires during follow-up visits. The total study duration includes initial diet phases, colonization, and several years of follow-up assessments.
CONDITIONS
Brief Title
O. Formigenes Colonization in Calcium Oxalate Kidney Stone Disease
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 19 to 70 years
- Body Mass Index greater than 18.5 kg/m2
- History of first time or recurrent calcium oxalate kidney stones
- Most recent kidney stone composed of at least 50% calcium oxalate, if available
- Not currently colonized with Oxalobacter formigenes
- Normal fasting serum electrolytes on comprehensive metabolic profile
- Willing to ingest fixed diets
- Willing to stop vitamins, calcium, minerals, herbal supplements, probiotics, and nutritional aids for 2 weeks before and during study diets
- Stable dose of medications for stone prevention for at least 2 weeks prior to and during study, if applicable
You will not qualify if you...
- Chronic Kidney Disease stage 4 or 5
- Primary hyperoxaluria
- Liver, endocrine, or kidney diseases other than idiopathic calcium oxalate stones that affect ion absorption or excretion, including cystic fibrosis, cystinuria, uric acid stones, nephrotic syndrome, sarcoidosis, renal tubular acidosis, primary hyperparathyroidism, neurogenic bladder, urinary diversion
- Pregnancy or breastfeeding
- Dietary restrictions incompatible with study menus, including food allergies or intolerances
- Active cancer or cancer treatment within 12 months prior to screening
- Use of immunosuppressive medication
- Uncontrolled hypertension or diabetes
- Type 1 diabetes
- Current colonization with Oxalobacter formigenes
AI-Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
Screening and enrollment visit
Duration - Approximately 2 to 3 weeks including diet periods and wash-out
Participants follow low and moderately high oxalate fixed diets with urine, stool, and blood sample collections to assess baseline oxalate excretion.
Several sample collections during diet periods with two 4-day diet phases separated by at least 1 week wash-out
Duration - 1 week
Participants ingest live Oxalobacter formigenes to induce colonization and provide stool samples to confirm colonization.
1 visit for ingestion and stool sample collection 1 week later
Duration - Approximately 2 to 3 weeks including diet periods and wash-out
Participants repeat low and moderately high oxalate fixed diets with urine, stool, and blood sample collections after colonization to evaluate changes.
Several sample collections during diet periods with two 4-day diet phases separated by at least 1 week wash-out
Duration - Up to 4 years
Participants are followed every 6 months to assess sustainability of colonization with stool samples and questionnaires, and annually provide urine collection on a controlled diet.
Visits every 6 months and annual urine collection
Trial Site Locations
Total: 2 locations
1
University of Alabama at Birmingham
Birmingham, Alabama, United States, 35294
Actively Recruiting
2
UTSW
Dallas, Texas, United States, 75390
Actively Recruiting
Research Team
S
Sonia Fargue, PhD
D
Demond Wiley
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SEQUENTIAL
Primary Purpose
BASIC_SCIENCE
Number of Arms
1
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