How fecal microbiota therapies help to cure infection

Clostridioides difficile (C. diff) is a bacterium that can cause diarrhea and inflammation of the colon (large intestine). Left untreated, infection can lead to serious complications and may be life-threatening. Each year, C. diff causes about 500,000 illnesses in the United States, according to the Centers for Disease Control and Prevention (CDC). The U.S. Food and Drug Administration (FDA) estimates it leads to between 15,000 and 30,000 deaths in the U.S. annually.

Fortunately, many stubborn, recurrent C. diff infections have met their match, thanks to fecal microbiota therapies. If you’re thinking that sounds suspiciously like putting someone else’s poop into your digestive system, you’re right. Here’s what to know.

What is C. diff?

C. diff is not typically a harmful part of the gut microbiome. The bacteria can make its way into your gut through contact with other infected people or via contaminated surfaces. C. diff is particularly common in healthcare settings and is one of the most common hospital-acquired infections in the U.S.

Once it’s in your intestines, C. diff bacteria can multiply if you’ve been on antibiotics that destroy other bacteria in your gut, but don’t kill C. diff. “Normal flora has an anti-C. diff effect,” says Bahri Bilir, MD, a gastroenterologist in Denver, Colorado.

When the other bacteria are gone, that allows C. diff to grow unchecked, leading to watery diarrhea, nausea, and abdominal pain. Without treatment, it can progress to life-threatening complications such as severe inflammation of the colon (large intestine), kidney failure, or a hole in the colon wall.

How does fecal microbiota therapy work?

C. diff infection is normally treated with antibiotics. But between 10 and 30 percent of people have a recurrence, according to the CDC. This is where fecal microbiota therapies can be most useful. They’re used to re-introduce the good bacteria into the digestive tract, which tamps down on C. diff’s growth.

You may be a good candidate for fecal microbiota therapy if you’ve had recurrent C. diff infections despite standard antibiotic treatment.

The material for fecal microbiota therapies comes from donors, who are screened for parasites and infectious diseases like HIV and hepatitis. It can be delivered a few different ways, which depends largely on the severity of the infection and a person’s overall health.

The first oral treatment, called VOWST, was approved by the FDA in 2023. A person prescribed VOWST would take four capsules once each day for three days in a row.

Some other methods of delivery are different types of a procedure called fecal microbiota transplantation. They include:

• Enema. Material is delivered through a tube placed in your rectum (last part of the colon), where it can make its way into your colon. This can be done in a physician’s office. In 2022, the FDA approved Rebyota, a single-dose treatment given via rectal enema.
• Colonoscopy. A tube is placed in the colon, and as it’s withdrawn, it deposits the donor material throughout the large intestine.
• Nasal tube. Material travels through a tube in your nose and into the small intestine.

After any fecal microbiota therapy, a healthcare provider will monitor your progress for several weeks and watch for recurrence. If there is no C. diff relapse after several weeks—eight weeks for VOWST—then it is often considered to be successful, though you may have follow-up over a longer term.

The future of fecal microbiota therapy

Though fecal microbiota therapies are considered generally safe and effective for recurrent C. diff infections, they remain relatively uncommon. But that may change as researchers explore their potential to treat inflammatory bowel disease, irritable bowel syndrome, and multiple sclerosis, among other conditions.