Using gut bacteria to reduce urinary oxalate in kidney stone patients

Oxalobacter Formigenes Colonization in Calcium Oxalate Kidney Stone Formers

Not applicable Interventional University of Alabama at Birmingham · NCT06330246

This study is testing if introducing a specific gut bacteria can help adults with calcium oxalate kidney stones lower the amount of oxalate in their urine.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years to 70 Years
SexAll
SponsorUniversity of Alabama at Birmingham Academic / other
Locations2 sites (Birmingham, Alabama and 1 other locations)
Trial IDNCT06330246 on ClinicalTrials.gov

What this trial studies

This trial aims to determine if colonization with the gut bacteria Oxalobacter formigenes can decrease urinary oxalate excretion in adults with calcium oxalate kidney stones. Participants will follow controlled diets with varying oxalate levels and provide urine, blood, and stool samples for analysis. The study will involve a pre-colonization phase with dietary monitoring followed by colonization with live Oxalobacter formigenes. The effectiveness of this intervention will be assessed by measuring changes in urinary oxalate levels.

Who should consider this trial

Good fit: Ideal candidates are adults aged 19-70 with a history of calcium oxalate kidney stones who are not already colonized with Oxalobacter formigenes.

Not a fit: Patients with chronic kidney disease stage 4-5 or primary hyperoxaluria may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could significantly reduce the risk of kidney stone formation in affected patients.

How similar studies have performed: While the use of gut bacteria for kidney stone prevention is a novel approach, similar studies have shown promise in other areas of gastrointestinal health.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria

* age 19-70 yrs
* Body Mass Index \> 18.5 kg/m2
* First time or recurrent Calcium Oxalate stone former. Composition of most recent stone ≥ 50% calcium oxalate if available
* Not colonized with Oxalobacter formigenes
* Normal fasting serum electrolytes on comprehensive metabolic profile
* Willing to ingest fixed diets
* Willing to stop supplements (vitamins including vitamin C, calcium (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics) for 2 weeks before start and during fixed diet phases.
* If on medications for stone prevention (e.g. thiazides, citrate, allopurinol), stable dose regimen for at least 2 weeks prior to and during study

Exclusion Criteria

* Chronic Kidney Disease stage 4-5
* Primary hyperoxaluria
* Liver, endocrine or renal diseases (other than idiopathic Calcium Oxalate kidney stones) or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results, including: Cystic fibrosis, Cystinuria, Uric acid stone former, Nephrotic syndrome, Sarcoidosis, Renal tubular acidosis, Primary hyperparathyroidism, Neurogenic bladder, Urinary diversion
* Pregnancy or breast-feeding
* Incompatible dietary requirements with the study, food allergies or intolerance to any of the foods in study menus
* Active malignancy or treatment for malignancy within 12 months prior to screening
* Utilization of immunosuppressive medication
* Uncontrolled Hypertension or diabetes
* Diabetes type 1
* Current Colonization with Oxalobacter formigenes

Where this trial is running

Birmingham, Alabama and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Kidney StoneKidney CalculiUrolithiasisUrolithiasis, Calcium OxalateNephrolithiasisNephrolithiasis, Calcium OxalateOxalate UrolithiasisOxaluria
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.