Human Feces Crossing A Milestone

Rebyota has revolutionized medical treatment for bacterial infections because of how it treats recurrent CDI and serves as proof of the increased understanding of the microbiome.

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By Chloe Huang

Do you excrete waste? Hopefully, your answer is yes. Human feces may be considered “gross” or “disgusting,” but it turns out that it is actually a tool in the field of epidemiology, or the study of health and disease. The Food and Drug Administration (FDA) has approved Rebyota, a new treatment that uses the bacteria in human fecal matter. This scientific milestone treats Clostridioides difficile infection (CDI), a devastating bacterial infection that causes inflammation of the colon (the longest part of the large intestine).

With about half a million cases and 15,000-30,000 deaths in the U.S. per year, CDI has destructive effects on humans. The bacteria C. difficile spreads through contaminated surfaces and then multiplies in the gut microbiome. From there, it can release toxins, triggering diarrhea, fever, inflammation of the colon (colitis), abdominal pain, and in many cases, organ failure or death. Additionally, one in six patients redevelops the infection within two weeks to two months of recovery. This is known as recurrent infections.

Prior to Rebyota, CDI was treated with antibiotics. However, certain antibiotics could worsen conditions and disrupt the balance of the gut microbiome when dealing with CDI. By the same token, the heavily antibiotic-resistant strains of C. difficile may be able to overcome the antibiotic treatments and persist. When this response becomes apparent, the use of these antibiotics is put to an end, and patients usually instead get treated with oral vancomycin or fidaxomicin, which are macrolide antibiotics that kill bacteria related to CDI. CDI should then resolve within two to three days.

Even then, there is only a 20 percent success rate and the possibility of re-infection. To make matters worse, there aren’t many FDA-approved treatments for this infection either. Fortunately, scientists have discovered the fecal microbiota product Rebyota.

Rebyota contains bacteria collected from the fecal matter of healthy, qualified human donors, and works to prevent CDI. Not only is Rebyota a solution to the issue of recurrent infections, but its approval marks a significant achievement in history since it is made from human fecal matter. Rebyota is a single-dose 150 mL suspension of bacteria administered through the rectum. The FDA approved a specific clinical program where fecal matter was tested for transmissible pathogens and allergens. If the tests did not detect any, it would then enter the clinical trials. In the clinical trials, participants with a history of CDI infection were treated with either Rebyota or a placebo, which was a harmless substance with no real pharmacological effect. Because there was an absence of diarrhea caused by CDI within eight weeks of the experiment, the treatment was declared successful. The results showed that a single dose of Rebyota performed better than the placebo and that 90 percent of the 70.46 percent of participants treated with Rebyota who did not get CDI diarrhea remained free of the infection for the following six months, proving that it helps fight recurring infections.

However, it is important to note Rebyota’s limitations. Rebyota should not be administered to those with histories of severe allergic reactions. Though donors are screened for pathogens, there still lies a possibility for Rebyota to contain food allergens even though the FDA is unsure if Rebyota can cause allergic reactions. Furthermore, clinical trials were not conducted on people below the age of 18 or over the age of 65, so these individuals should avoid the treatment as well. In addition, common side effects include stomach pain, diarrhea, bloating, and nausea. This may sound like a long list of drawbacks, but Rebyota is able to do what previous CDI treatments were unable to: prevent recurrent infections.

Rebyota being able to combat recurrent infections is a great step in the right direction of lessening the impact of CDI. Now, we can not only treat recurrent CDI infections, but we understand the gut microbiome better than ever before. There are countless diseases that we lack knowledge about, restraining us from treating them. However, with this newfound knowledge, we can further study many of these diseases and combat them, creating lasting impacts in the field of epidemiology.