The human gastrointestinal tract is a complex body system that also happens to be home to trillions of microorganisms. This community of gut microbes, known collectively as the gut microbiome, is known to play a crucial role in our digestive health; in recent years, though, researchers have discovered that these intestinal microbiota have an impact on numerous other aspects of health. It is for this reason that new medical procedures have been developed to enhance, heal, or rebalance the composition of microbes. One procedure that has shown a lot of promise in improving the microbiome is referred to as fecal microbial transplantation (FMT).

What is Fecal Microbiota Transplantation?

Also known as fecal transplant or stool transplant, a fecal microbiota transplantation (sometimes spelled faecal microbiota transplantation) is a medical procedure that involves transferring fecal matter from a healthy donor into the gastrointestinal tract of a recipient. The goal of this process is to restore or modify the microbial composition of the recipient’s gut microbiome by introducing healthier gut microbiota from the donor stool. The use of FMT is usually prompted by the presence of certain infectious diseases, but there is also evidence it may be helpful in treating various other conditions.

How Does the FMT Treatment Work?

During a fecal microbiota transplantation, fecal material is first obtained from a healthy donor whose feces have been through stool tests that look for gastrointestinal diseases and other abnormalities. Once a stool sample has been determined to be healthy, it is combined with a saline solution to create a fecal suspension. This material is then introduced to the recipient’s gastrointestinal tract through one of several different methods:

  • Colonoscopy: Colonoscopy is the most common method, largely because it allows for the precise placement of the stool suspension in the colon. The procedure involves inserting a flexible tube with a camera on the end (colonoscope) into the colon via the rectum. The fecal material is delivered through the colonoscope and into the colon, where it can colonize the gut microbiota.
  • Nasogastric tube: Fecal material can also be delivered to the stomach or small intestine using a nasogastric tube; the tube is inserted through the nose, down the esophagus, and into the stomach. The stool suspension is then sent through the tube and into the upper gastrointestinal tract where it can mix with gastric juices and move through the digestive system. This option is often used for patients who are unable to undergo colonoscopy or prefer a less invasive approach.
  • Enema: For patients who are unable to tolerate either a colonoscopy or nasogastric tube insertion, FMT can also be administered using a retention enema. This involves flushing the solution into the rectum through a tube. Enemas are less invasive than colonoscopy, but they may also be less effective for reaching higher regions of the colon.
  • Capsule: By far the least invasive option is a capsule FMT. This involves swallowing a dissolvable capsule that contains frozen, dehydrated fecal matter from a donor. It is swallowed like a regular pill, but the stool suspension is only released once in the gastrointestinal tract. While a capsule FMT offers a non-invasive and convenient method of delivery, it may be less effective than other methods due to variability in transit time and degradation of the stool material in the stomach.

Why Would a Fecal Microbiota Transplantation Be Necessary?

There are various reasons why a fecal transplant might be recommended to a patient, but it is primarily used as a treatment for a recurrent Clostridioides difficile infection (CDI). C. difficile is a common bacteria that can infect the colon and cause symptoms like diarrhea, nausea, and abdominal pain. Though there are many ways to develop a C. difficile infection, it often arises after antibiotic therapy that is prescribed for another condition. Below are some other reasons your healthcare provider may prescribe a FMT:

As a therapeutic treatment, fecal transplant is a relatively new innovation. In fact, it was only just approved for treatment of recurrent CDI by the U.S. Food and Drug Administration (FDA) in 2023. So far it has only been approved for treating C. diff infections that haven’t responded to standard bacteriotherapy or antibiotic treatment. Some of the other potential uses noted above are still being researched, though there is some evidence that the procedure may be helpful in other ways.

Potential Side Effects and Complications

Fecal microbiota transplantation is generally considered a safe and effective treatment for recurrent CDI, and it has become the go-to method of treatment in recent years. Like all medical procedures, however, there are always some possible risks and complications, particularly when the procedure is used for other conditions. Although they are rare, below are some of these possible side effects and complications:

  • Infection transmission: Since FMT involves the transfer of stool from a donor to a recipient, there is always some risk that the donor stool could transmit a pathogen or bacterial infection to the recipient. The risk of infection in this way is usually mitigated by the necessary stool tests prior to transplantation, but it remains possible that an undetected pathogen could be transmitted.
  • Gastrointestinal symptoms: Due to the nature of the procedure and the process of changing the makeup of the gut microbiome, it is also fairly normal for the recipient to experience common gastrointestinal symptoms after the procedure. These symptoms usually resolve on their own after a few days. Examples of symptoms include bloating, cramping, constipation, diarrhea, or a change in the frequency of bowel movements.
  • Allergic reactions: In rare cases, recipients may experience an allergic reaction to a substance contained in the donor stool. Symptoms of an allergic reaction may include rash, itching, swelling, difficulty breathing, or anaphylaxis.
  • Dysbiosis: While the ultimate goal of a fecal transplant is to restore the gut microbiome to a healthier state, it’s possible that the donor’s stool can actually cause additional imbalances (dysbiosis) in the composition and diversity of the microbiome.

Much of the research into fecal microbiota transplantation has focused specifically on the effectiveness of the procedure at treating CDI. Numerous clinical trials and meta-analyses have shown that it works and is safe, but there are still questions about the long-term effects on gut health and overall wellbeing. And since it is a relatively new procedure, there is always a non-zero chance of unknown risks.

Cary Gastroenterology for Digestive Healthcare

As strange as it may sound to get a fecal transplant, research has shown that it is one of the most effective treatments for C. difficile infections. The procedure may also be helpful for other microbiome-related conditions, but studies are still ongoing. If you have been experiencing persistent gastrointestinal symptoms, it may be time to get checked out by a gastroenterologist. Please contact Cary Gastro today to request an appointment.