A (Frozen) Boost For Fecal Transplants To Treat Nasty Bacterium

By Gabrielle Emanuel

Last month, we reported on the first national stool bank and its struggle to survive. This week, a pilot study, published online in Clinical Infectious Diseases, gives the stool bank a helpful boost.

The study found frozen stool from an unrelated donor to be as effective in treating patients as fresh feces taken from the patient’s family member. It also found that the transplant can be successfully administered through the nose.

Before you stop reading, here's some background: A stool bank is just like a blood bank, but instead of collecting, testing and distributing blood, it works with fecal matter. The main beneficiaries are patients with recurrent Clostridium difficile (C. diff). C. diff is a nasty bacterium that causes such bad diarrhea it can completely disrupt a person’s life. Over the course of a year, it sickens half a million people and kills about 14,000 people in the U.S.

Luckily, there is a very effective treatment: fecal transplants. This is when you take stool from a healthy donor and put it into the gut of a sick patient; the good bacteria then outfights the C. diff. Studies involving animals and fresh fecal material show that this procedure works 90 percent of the time.

“It's been remarkably successful and gratifying," said Dr. Elizabeth Hohmann, an associate professor of medicine and infectious diseases at Massachusetts General Hospital and Harvard Medical School, and the study's senior author. "There aren't that many things we do in medicine that are over 90 percent effective."

Despite such a success rate, many doctors are unwilling to do the procedure. One of the main reasons is that finding and screening donors takes a lot of time and can be expensive.

When Mark Smith, a PhD student at MIT, heard about this he decided to partner with some friends and start a stool bank. The thought was that if they provide prescreened, frozen stool, the procedure would be way easier and, thus, boost its availability. Their stool bank has been fully operational since early October.

But the FDA was more cautious.

In March, the agency released draft guidelines that cast the future of the stool bank in doubt. The FDA was eager to gather more data on the effectiveness of fecal transplants. "They want to understand how this works," Hohmann said.

There were a few looming questions that worried everyone. One was whether frozen stool is as effective as fresh stool. And then there is also the question of how best to administer the material.

Now, there may be some preliminary answers.

Frozen Vs. Fresh

The pilot study by Hohmann and fellow researchers at MGH found that frozen stool from prescreened donors who were unrelated to the patient was very effective. Indeed, it was just as effective as fresh feces taken from the patient’s family member. This confirms earlier findings.

There had been a worry that "when you freeze material, the important bacteria could die." But Hohmann says the study shows otherwise.

Using frozen material — which is what the stool bank uses — has the potential to be much cheaper and faster than the fresh method. With the frozen approach, when one donor is screened for parasites and infections, their material can be used to help numerous patients.

Hohmann says this will also be helpful for patients. It clears the way for them to "use the [screening] of very healthy, normal adult volunteers instead of making the patient find a donor," which can be quite challenging, particularly for older, sicker patients.

Getting To The Gut

The study, which enrolled 20 patients ages 2 to 90 with recurrent C. diff, also tested how best to insert the sample. There are two main hospital-based options: a colonoscopy, which involves inserting it through the rear; or a nasogastric tube, which entails threading a feeding tube from the nose down to the stomach. Ten patients got their fecal transplant through a colonoscopy and 10 patients got the nasogastric tube.

The researchers found no statistical difference between the two procedures.

In addition, the researchers treated 11 other patients with frozen feces using a nasogastric tube. There too they had a 90 percent success rate.

The nasogastric tube is the easier of the two options. Hohmann explained that a “colonoscopy is a significant procedure requiring sedation," while the nasogastric method "is an outpatient office procedure." Hohmann says this is especially good news for frail or elderly patients who may have a hard time with a colonoscopy.

The results of this study suggest it may be possible to do fecal transplants in a cheaper and easier fashion that is equally safe and effective.

Hohmann says she hopes that it will convince more doctors to start offering fecal transplants as they begin to "understand that this is something they can do on an outpatient basis."

The researchers are already looking at even simpler transplant methods. They are testing whether a poop pill — a capsule with no tubes required — is feasible. So far, 20 patients have been treated this way, and early results are "going very well," Hohmann reports.

Researchers envision a day when C. diff patients can wash down their fecal transplant with a swig of water — the easiest option of all.


More from WBUR

Listen Live