Last January, a phase 3 study was published in a prestigious scientific journal, the New England Journal of Medicine, testing an improved treatment for patients with recurrent intestinal infections. The clinical trial focused on patients suffering from infections caused by a specific bacterium, Clostridioides difficile. These patients suffer from recurrent infections from time to time and it represents a very marked deterioration in the quality of life, and can cause very serious damage to the body.
The influence of the microbiota
The microbiota can be defined as the set of microorganisms that coexist in the same habitat, from bacteria to algae. However, when we talk specifically about our microbiota, we are usually referring to hundreds of different types of bacteria and viruses that go with us everywhere. We can find populations of microorganisms inside us, such as in the intestine, and also on our skin. And what are so many microorganisms doing inside our body? Well, depending on the type of microorganism, they can go completely unnoticed, give us some advantage or be harmful to us. These three types of relationships are known as commensalism, mutualism, or parasitism. Sometimes, if two species benefit from living together, they are also known as symbiont species.
The study of the human microbiota and its communication network with our body is a relatively recent field of study. The Human Microbiome Project initiative launched in 2007 aimed to identify and characterize the human microbiota not only in diseases but also in healthy individuals. Many studies have emerged from this initiative that focus on a specific type of disease or microorganism. Today, the evidence indicates that we have the same number of cells of these microorganisms.
In recent years, it has been deciphered how the intestinal microbiota can have such a decisive effect on various diseases. Although this relationship has also been found in metabolic and neurological diseases, the ones that have received the most attention are those diseases that have the intestine as the main organ affected. Although many elements of the close communication that takes place between thousands of microbes and our own cells are still unknown, it is clear that an imbalance in this balance can have serious consequences.
Based on this evidence, fecal transplants have been successfully performed from healthy donors to patients suffering from different intestinal diseases. In most cases, beneficial but limited results have been observed, although there have also been disastrous results that have culminated in the death of the patient. One possible explanation for this effect, according to the experts, lies in the fact that in fecal transplantation it is not possible to maintain strict controls on the transplanted content, posing a risk to the person receiving the transplant.
A new proposal of a known practice
For this reason, the idea arose of designing poop pills that could pass production controls and ensure that they only contained beneficial elements for the recipient. The process consisted of choosing four healthy donors, from which their feces were obtained and a specific type of bacteria was isolated: Firmicutes. Afterwards, the researchers were left with only the spores of these bacteria. These spores would be an inert form of the bacteria, and for this reason they are easier to isolate and preserve in the form of tablets.
The study was conducted on 182 patients with recurrent infections, of whom only half received this pill in combination with standard antibiotic treatment. The objective was to check if the effect of the poop pill was an additional benefit compared to the other half of patients who only received antibiotics.
All patients were followed up for eight weeks after the start of treatment , and those who received the pill of each had a lower rate of reinfection than those who received standard antibiotic treatment (12% vs. 40% of patients with reinfection). The lower reinfection rate was also confirmed with different parameters used to determine bacterial germination.
Although this study has some population representation limitations and patient follow-up is somewhat short, it presents an interesting alternative to the treatment of intestinal diseases. In addition, this study delimits the beneficial factors of fecal transplantation to a single type of bacteria, the Firmicutes . Although within this group, there are very different bacteria, perhaps in the future it could be reduced even further and thus optimize this type of treatment.
It would be of special interest to be able to develop an effective pill that can be standardized and perhaps implemented as an additional treatment for different intestinal diseases where the microbiota plays an important role.
Feuerstadt et al. 2022. SER-109, an Oral Microbiome Therapy for Recurrent Clostridioides difficile Infection. N Engl J Med. doi: 10.1056/NEJMoa2106516
DeFilipp et al. 2019. Drug-resistant E. coli Bacteremia Transmitted by Fecal Microbiota Transplant. N Engl J Med. doi: 10.1056/NEJMoa1910437
Human Microbiome Project. Project founded in 2007 and financed by the National Institute of Health of the United States.