Donor FAQ

The body contains a dense population of microorganisms in the lower intestine, or colon. These microbes form an important part of your digestive system that can help to digest certain foods. They also participate in various other parts of human physiology and contribute to regulation of metabolism and instruction of the immune system. The microorganisms that normally reside in the colon are highly specialized and organized into a community. The term microbiota refers to the entire communities of these microorganisms, which are engrafted into the recipient intestines during the procedure.

There are very simple, fast, and accurate stool tests that are used to diagnosed this infection. People are most vulnerable to catching C. difficile infection during or after treatment with antibiotics. Normal microbial communities in the gut are able to keep C. difficile in check, but antibiotics suppress the normal microbes creating a state vulnerable to infection. Intestinal microbial communities may not return to a normal state for up to several months after taking antibiotics. An individual can become infected if he or she comes into contact with C. difficile spores, which germinate in the intestine, giving rise to vegetative forms of bacteria that produce toxins. It is the toxins that make people sick. The usual symptoms are diarrhea. However, sometimes people can become extremely ill with high fever and their colon may stop working altogether. The standard treatment for C. difficile infection is more antibiotics. C. difficile is resistant to most antibiotics, but there are some that can suppress it, including metronidazole (Flagyl), vancomycin (Vancocin), rifaximin (Xifaxan), and fidaxomicin (Dificid). However, even these antibiotics cannot get rid of all the C. difficile spores, and their administration can perpetuate the infection because they also continue to inhibit the normal microbes. Therefore, the infection can come back once the anti-C. difficile antibiotics are stopped. Patients commonly develop a cyclical pattern of infection – treatment – recurrent infection. Every recurrence increases the chances of failure of antibiotic therapy, and some patients can develop multiply recurrent C. difficile infection syndrome.

During this procedure normal microbial communities are introduced into the colon, and reestablish its normal microbial composition. There are a number of theories that may explain how normal microbes keep C. difficile in check. This is an area of active research and we are keenly interested in this question.

We do not put in stool into patients! We implant microbial communities or microbiota. In our program we separate the microbial fraction from the fecal material of healthy donors in the laboratory. These microbes, which are mostly bacteria, are held in a freezer with a preservative in a frozen suspension. The material cannot be released for clinical use until all up-to-date testing is completed on the donor and the material itself. Each person’s fecal microbiota are made up of hundreds of different microbial species, and the composition is somewhat different in each person. However, there are more similarities than differences. In patients with recurrent C. difficile infection syndrome, very few normal bacteria are left. When a new microbial community is introduced, it quickly takes up residence and reconstructs the damaged microbial gut ecology. The vast majority of IMT procedures in our program are done via a colonoscopy. We have the most experience with this route of administration, which also allows a diagnostic examination of the colon. Some patients may qualify for an oral form of IMT during which they swallow encapsulated preparations of microbiota. Regardless of route of administration, the patients need to remain on an antibiotic to suppress C. difficile until 2 days prior to the procedure. Keeping C. difficile suppressed with antibiotics gives the new bacteria the best chance of succeeding.

The overall success rate in the literature is about 90%. A randomized trial was reported from the Netherlands in January of 2013 in the New England Journal of Medicine reporting > 80% success rate. That trial was stopped early because the antibiotic group was doing much worse. Since the program’s inception in 2008, our center has experienced a 90% success rate with one infusion attempt (> 220 patients, years 2008-2014). Patients who fail cure with one attempt can receive another FMT, which brings the success rate to 98%.

The procedure appears to be very safe, although the data are limited to large case series and only one small, randomized trial. Patients with underlying inflammatory bowel disease can experience a transient flare of colitis, although in the long run they generally do better after ridding themselves of C. difficile infection. Since the transplant material is derived from feces, proper donor screening and testing is essential. Our donors go through many steps to be qualified. They complete a large questionnaire, which includes a section similar to one done at the blood banks, but in addition the questions screen for metabolic, gastrointestinal, immunologic, and neurologic disorders. The donors undergo a full history and physical examination, and are tested for various systemic infections, including HIV, hepatitis, syphilis, as well as metabolic and autoimmune problems. The stool is tested for various enteric infections, including C. difficile. However, it is important to emphasize that some risks remain unknown since we may not know all the pathogenic organisms that exist. Some microbes may be able to cause problems only in certain individuals, e.g., people with a weak immune system. So far, limited evidence collected from a number of centers suggests this risk is very small.