Although some practitioners routinely use Imodium, we do not recommend it when material is administered into the proximal colon or terminal ileum.

Colonoscopic route has the most accumulated experience and is the preferred route. If the upper route is used, the microbiota should be delivered in a smaller volume. We recommend limiting the volume to 35 ml for the upper route of administration, which is the volume of the suspension in the cryobag. Furthermore, we recommend injecting the material distal to the ligament of Treitz. If endoscopic administration is not feasible, a nasoduodenal tube, confirmed by imaging, is acceptable. After administering the microbiota the endoscope or the nasoduodenal tube should be flushed with an equal volume of normal saline.

Careful visualization of the colon is generally best done during scope withdrawal and requires suction. Therefore, generally, investigational FMT colonoscopy is not well suited for screening. However, in some patients this may be the only colonoscopy they will agree to have. Also, we advise to defer any elective colonoscopy for at least 6 months after investigational FMT to minimize chances of purgative-induced relapse of C. difficile infection. It may be possible to complete the screening colonoscopy first (insertion and withdrawal) and re-insert the scope for investigational FMT during the same endoscopy session.

This will depend on the circumstances of your patient but generally speaking it is safe to biopsy during procedure. Recurrent CDI and microscopic colitis are both most common in older females and investigating both causes for diarrhea may warrant biopsy during investigational FMT. Sometimes it is possible that the underlying microscopic colitis is the real or an equally important driver of patient’s symptoms. Mucosal biopsies are generally recommended for work-up of diarrhea if there is any diagnostic uncertainty. However, we would not recommend extensive biopsies for IBD dysplasia surveillance during an investigational FMT colonoscopy.

We estimate the risk of C. difficile infection to be ~15-20% with every new antibiotic provocation. It is important to consider this risk in determining patient candidacy for investigational FMT, timing of the treatment, and post-investigational FMT counseling. The following are some of the considerations:

1. If the patient is anticipated to have surgery in the near future, consider delaying the investigational FMT until after that procedure. The patient’s C. difficile infection can be suppressed with low dose vancomycin (125 mg PO daily).
2. Consider surgical antibiotic prophylaxis with IV vancomycin (1g) if needed. Vancomycin administered intravenously only minimally penetrates into the gut.
3. Occasional uncomplicated urinary tract infections can be treated with a 3-day gentamicin pulse regimen (one dose per day given IV or IM) (Staley, C., et al., ‘Gut-sparing treatment of urinary tract infection in patients at high risk of Clostridium difficile infection’, J Antimicrob Chemother 2017; 72: 522–528. No oral antibiotic for UTIs is completely safe, but their relative risk varies (e.g., Ciprofloxacin > Bactrim).
4. Encourage adherence to professional guidelines for antibiotic prophylaxis for dental and other procedures in patients with prosthetic joints, prosthetic cardiac valves, and other high risk populations.
5. Different antibiotics have varying risk for triggering C. difficile infection (e.g., clindamycin > cephalosporins = fluoroquinolones = ammoxicillin-clavulanate > macrolides > amoxicillin = nitrofurantoin = tetracycline) (Brown KA, et al., ‘Antibiotic Prescribing Choices and Their Comparative C. Difficile Infection Risks: A Longitudinal Case-Cohort Study’, Clinical Infectious Diseases 2021, 72:836–844.

C. difficile infection in IBD patients is associated with greater morbidity. However, it is often unclear whether C. difficile is driving IBD activity or merely colonizes patients with more severe IBD. C. difficile infection should be treated in IBD patients. However, we recommend investigational FMT to be administered after the immunosuppressive therapies for IBD have been optimized to minimize the risk of IBD flare that could be triggered by investigational FMT.

Investigational FMT is not contraindicated in patients with cirrhosis being treated for recurrent C. difficile infection. However, the burden of antibiotics is very high in this patient population and the duration of benefit may be limited.