Frozen Samples May Expand Fecal Transplant Use

Using frozen stool samples may help expand treatment with fecal microbiota transplant for Clostridium difficile infection. (Image: ©AMA)

Using frozen stool samples may help expand treatment with fecal microbiota transplant for Clostridium difficile infection. (Image: ©AMA)

Using stool from healthy, unrelated donors that has been frozen could expand the availability of a promising treatment for potentially deadly Clostridium difficile infection, a new study suggests.

Known as fecal microbiota transplant (FMT), the treatment consists of taking stool from a healthy donor, often a family member, and transplanting it into patients via colonoscopy or a nasogastric tube. The goal is transferring “good” bacteria to help fight infection in the patient’s gut. Studies in recent years have shown FMT using fresh stool is about 90% effective in curing C difficile infection or preventing a recurrence.

But using fresh fecal material has several disadvantages: screened donors must be readily available and obtaining, processing, and delivering the sample has to be done in a limited time frame. If nonrelatives gave samples that could be screened, frozen, and banked, physicians could overcome some of those hurdles.

In today’s Clinical Infectious Diseases, researchers at Massachusetts General Hospital in Boston report on a pilot study using thoroughly screened frozen samples from healthy nonrelatives who were instructed not to eat common allergens such as eggs or nuts for several days before donation.

The investigators enrolled 20 patients, including 3 children, with C difficile infection that didn’t respond to antibiotics or was severe enough to require hospitalization. Half received thawed donor fecal material through a nasogastric tube and the other half via colonoscopy. Patients can’t smell or taste material delivered through the tube.

After a single treatment, diarrhea resolved within 8 weeks without a relapse in 14 patients. Retreatment stopped diarrhea in 4 of 5 patients. The 90% overall cure rate is comparable to previous studies, and outcomes were the same regardless of whether colonoscopy or a nasogastric tube was used.

“It’s been very gratifying to be able to help these patients, some of whom have been sick for a year or 2,” senior author Elizabeth Hohmann, MD, said in a statement.

An 89-year-old woman in the study had 16 documented episodes of infection, including 4 regular admissions and 2 intensive care unit admissions. She was cured with 2 treatments and has been asymptomatic for more than 12 months.

Patients taking antibiotics are vulnerable to intestinal infection because the drugs disrupt bacteria that naturally live in the colon. C difficile produces toxins that can cause watery diarrhea, fever, loss of appetite, nausea, and abdominal pain and tenderness. In severe cases, toxins attack the lining of the colon, and surgery may be needed to remove infected tissue. About 14 000 US deaths a year are C difficile–related.

Fecal microbiota transplant was introduced as an effective treatment more than 50 years ago but never came into wide use. Hohmann said that may start to change.

“There aren’t many things in medicine that have a success rate of more than 90%,” she said. “[Fecal microbiota transplant] is very effective, makes patients better quickly, and saves money overall. While it may never become a first-line treatment, we are starting to consider using it more and more often.”


Categories: Bacterial Infections, Infectious Diseases, Public Health