Is re-sampling of stool necessary to assess for Clostridioides difficile (C. diff) resolution?

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Last updated: April 9, 2025View editorial policy

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From the Guidelines

No, you do not need to resample stool to assess for C. difficile resolution after treatment. This recommendation is based on the 2018 clinical practice guidelines for Clostridium difficile infection in adults and children by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) 1. The guidelines advise against repeat testing for CDI in the absence of clear changes to the clinical presentation, as the diagnostic yield of repeat testing within a 7-day period is approximately 2%.

Key points to consider:

  • The persistence of C. difficile toxins and organisms in stool for weeks after clinical symptoms have resolved does not indicate active infection requiring additional treatment 1.
  • Resolution of CDI should be determined by the improvement of clinical symptoms, particularly the normalization of stool frequency and consistency.
  • Patients should be considered clinically cured when they have fewer than three unformed stools per day.
  • If symptoms recur after initial improvement, then retesting is appropriate as this may indicate a relapse or reinfection, which occurs in approximately 20-30% of cases.
  • Treatment decisions should be based on clinical assessment rather than laboratory results in patients who have completed an appropriate course of therapy, as unnecessary testing can lead to overtreatment 1.

From the Research

Assessment of C. Diff Resolution

To assess for C. Diff resolution, the need for re-sampling stool is not explicitly mentioned in the provided studies. However, the studies discuss various treatment options and their effectiveness in resolving C. Diff infection.

Treatment Options

  • Vancomycin is recommended as the first-line therapy for most cases of CDI 2, 3.
  • Fidaxomicin is a good alternative, especially in patients at risk of relapse 2, 3.
  • Metronidazole is associated with lower rates of treatment success compared to vancomycin and should no longer be used as primary therapy for the first episode of CDI or recurrent disease 3.
  • Fecal microbiota transplant is effective and safe for the treatment of recurrent CDI 2, 3.

Recurrence and Resolution

  • The recurrence rate of C. Diff infection remains high, up to 20% 2.
  • Fidaxomicin has been shown to be superior to metronidazole, vancomycin, or their combination for a sustained clinical response and in the prevention of recurrent CDI in some studies 4, 5.
  • However, fidaxomicin was inferior to metronidazole for recurrent CDI in one study 4.

Cost-Effectiveness

  • The cost-effectiveness of treatment regimens for CDI has been evaluated, and the preferred treatment regimen is fidaxomicin for nonsevere CDI, vancomycin for severe CDI, fidaxomicin for first recurrence, and FMT for subsequent recurrence 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Update of treatment algorithms for Clostridium difficile infection.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 2018

Research

Fidaxomicin versus metronidazole, vancomycin and their combination for initial episode, first recurrence and severe Clostridioides difficile infection - An observational cohort study.

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, 2021

Research

Cost-effectiveness of Treatment Regimens for Clostridioides difficile Infection: An Evaluation of the 2018 Infectious Diseases Society of America Guidelines.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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