DEAR MAYO CLINIC: I’ve had recurring instances of C. diff. that normally is treated with antibiotics. I have read about fecal transplant as a potential treatment. How does this work?
ANSWER: Clostridium difficile, also known as Clostridioides difficile and often called C. diff., is a bacterium that causes gastrointestinal symptoms ranging from diarrhea to life-threatening inflammation of the colon. In many cases, antibiotics are an effective treatment. If the infection recurs after two or three rounds of antibiotics, a fecal transplant may be an appropriate alternative.
C. diff. bacteria are found throughout the environment — in soil; air; water; human and animal feces; and food products, such as processed meats. C. diff. is now the most common infection affecting hospital patients. The most common risk factors for C. diff. are taking antibiotics, being older than 65, and being in a hospital or other health care facility.
Taking antibiotics can lead to C. diff. infection by disrupting the healthy balance of bacteria that’s normally present in your intestines. The intestines contain about 1,000–2,000 different kinds of bacteria. Many of them help protect your body from infection. When you take antibiotics to treat an infection, such as for a sinus, urinary tract or kidney infection, those drugs destroy many of the helpful bacteria in the gut along with the bacteria causing the infection. Without enough healthy bacteria to keep it in check, C. diff. quickly can grow out of control.
While antibiotics can contribute to C. diff. infection, some antibiotics, such as vancomycin or fidaxomicin, also can effectively eliminate C. diff. infection. In about 75% to 80% of people who get C. diff., one round of antibiotics is enough to get rid of the infection and prevent it from recurring.
For the other 20% to 25%, a recurrence happens because the antibiotics again take out too much of the good bacteria with the C. diff. Once C. diff. infection recurs, the chances of it returning again after a second round of antibiotics is 40%. After three or more occurrences, the risk of another infection rises to 60%.
One way to break the cycle of recurrent infections is to restore the natural balance of healthy bacteria in the intestines. This can be done through a process known as fecal microbiota transplantation. The procedure — considered investigational at this time — restores healthy intestinal bacteria by placing another person’s processed stool into the colon of a person affected by recurrent C. diff. infections.
Potential donors need to go through a strict screening process that involves an extensive list of medical history questions before they can be approved as donors. They also need to undergo comprehensive testing for infections in the blood and stool.
Once a donor is approved, his or her stool is collected, mixed with saline water and filtered. Then the stool mixture is transferred into the patient’s colon, most commonly via a colonoscope — a thin, flexible tube with a small camera at the tip.
The procedure is considered to be generally safe. The Food and Drug Administration, however, recently released a report about two patients who underwent fecal transplantation and contracted drug-resistant infections. It’s unclear if these cases were related to fecal transplants for C. diff. or if the fecal transplants were done for another condition. More needs to be learned about those incidents, but they speak to the importance of carefully and methodically screening donors.
Clinical trials to study fecal transplants are underway at medical centers across the country, including Mayo Clinic. So far, research has shown that this procedure can reduce the risk of contracting another C. diff. infection in people who have had three or more of the infections. In this patient population, the risk has been reduced from 60% down to less than 15%. With these findings in mind, this treatment appears to show significant promise in providing a more effective treatment option for recurrent C. diff. infections. — Dr. Sahil Khanna, Gastroenterology, Mayo Clinic, Rochester, Minnesota