Stool C. difficile toxin levels after standard antibiotics for a first recurrence

A Prospective, Observational Study to Evaluate C. Difficile Toxin Levels in Stool in Healthy Individuals Following Standard of Care Antibiotic Treatment for CDI.

This project will test whether stool toxin A or B levels predict recurrence in adults who just completed standard antibiotic treatment for their first recurrent C. difficile infection.

Quick facts

• Study type: Observational
• Enrollment: 60 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Bactolife A/S (industry)
• Locations: 1 site (Atlanta, Georgia)
• Trial ID: NCT07250724 on ClinicalTrials.gov

What this trial studies

This is a prospective observational study that will enroll about 60 otherwise healthy adults with a documented first recurrent C. difficile infection. Participants must have completed standard oral antibiotic therapy no more than five days before enrollment and be asymptomatic, and only those with a positive stool toxin B at baseline are considered enrolled. Stool samples will be collected at baseline, week 2, and week 8, with clinical follow-up over an 8-week period to record recurrence. The study will measure recurrence rate and correlate quantitative toxin A and B levels using high-sensitivity assays with subsequent rCDI.

Who should consider this trial

Good fit: Adults 18–75 with a documented first recurrent C. difficile infection who completed standard oral antibiotics within five days, are currently asymptomatic, and who test positive for toxin B in stool are ideal candidates.

Not a fit: Patients with an active CDI episode or unresolved symptoms, toxin A–positive/toxin B–negative test results, or those planning alternative recurrence treatments (e.g., FMT) during the study are unlikely to benefit.

Why it matters

Potential benefit: If successful, this could help clinicians identify patients at higher risk of recurrence so they can offer targeted prevention or closer follow-up.

How similar studies have performed: Prior work on stool toxin detection has shown variable results with older assays, and high-sensitivity toxin testing is promising but not yet widely validated for predicting recurrence.

Eligibility criteria

Inclusion Criteria:

* Able to provide signed and dated informed consent
* Males and females between 18 - 75 years old inclusive
* Documented history of first recurrent Clostridioides difficile (former Clostridium difficile) infection (rCDI), confirmed by a positive C. difficile test (Toxin A+B positive or Toxin B only), with initial infection occurring within the previous 12-months.
* Must, in accordance with standard of care practices, have completed a SOC oral antibiotic therapy for the first rCDI no more than 5 days prior to the date of enrolment (baseline visit- Day 0).
* Must not have any CDI-related symptoms when enrolled in the study at baseline (Day 0).

Exclusion Criteria:

* Current episode of CDI or delayed symptom resolution from previous recurrence, according to the physical exam and investigator assessment
* Toxin A positive, and Toxin B negative C. difficile test.
* Planned CDI recurrence treatment for the duration of the study e.g., fecal microbiome transplant, probiotics, Live Biotherapeutic Products (LBPs)
* Those who are on further antibiotic treatment following initial rCDI antibiotic therapy completion.
* Pregnant or lactating women or women who intend to become pregnant within the next 3 months.
* Subjects presenting with active diarrhoea (3 or more stools per 24-hour period) and within Bristol stool scale range of 5-7 at baseline.
* Has any significant acute or chronic coexisting health conditions that would prevent them from fulfilling the study requirements, put the Participant at risk or would confound the interpretation of the study results as judged by the investigator on the basis of medical history and routine laboratory test results.

  * Ostomized participants, parenteral nutrition users
  * Patients with active Pancreatitis
  * Active, non-controlled intestinal diseases such as IBS, IBD, Crohn's Disease, ulcerative colitis, celiac disease, or other chronic diarrheal illness
* Currently or recently taking a medication that the investigator believes would interfere with the objectives of the study or pose a safety risk or confound the interpretation of the study results.
* Individuals who, in the opinion of the investigator, are considered to be poor attendees or unlikely for any reason to be able to comply with the study.
* Participants may not be participating in other clinical studies. If the participant has previously taken part in an experimental study, the Investigator must ensure sufficient time has elapsed before entry to this study to ensure the integrity of the results.

Where this trial is running

Atlanta, Georgia

• Emory University Hospital — Atlanta, Georgia, United States (RECRUITING)

Study contacts

• Study coordinator: Kevin O' Regan Senior Operations Manager, Atlantia Clinical Trials

Conditions: Clostridioides Difficile Infection Recurrence, C. Diff, Clostridioides Difficile, Clostridioides Difficile Infection, Clostridioides Difficile Recurrence, C. Diff recurrence