Gut bacteria
A randomized, controlled study of 25 patients has demonstrated that an autologous fecal microbiota transplant (auto-FMT) can restore beneficial gut bacteria depleted during allogeneic hematopoietic stem cell transplant (auto-HSCT), according to researchers.
Antibiotics given to prevent and treat bacterial infections during HSCT can also destroy patients’ beneficial intestinal bacteria, increasing their risk for infections and graft-versus-host disease.
The researchers reported that auto-FMT is a safe and effective way to help replenish the beneficial bacteria to near baseline levels within days.
Study patients receiving HSCT at Memorial Sloan Kettering Cancer Center (MSKCC) in New York provided fecal samples collected before transplant conditioning, which were frozen and stored before undergoing transplant.
Between 1 and 5 weeks, when physicians could confirm that patients’ stem cells had engrafted, they collected another fecal sample from patients and randomized the first 25 who lacked known beneficial bacteria to one of two groups.
Eleven control patients received standard of care without fecal transplant and 14 received auto-FMT by enema.
Researchers followed the subjects for 1 year after randomization, with fecal samples collected during this time.
Eleven of the 14 patients (79%) in the auto-FMT group recovered 75% or more of their initial good gut bacteria within days. This helped restore their digestive, immune, and other essential functions.
The beneficial microbial groups restored included Lachnospiraceae (family), Ruminococcaceae (family), and Bacteroidetes (phylum).
Patients in the standard care group took many weeks to replenish the beneficial bacteria destroyed during antibiotic treatment. Only 3 of 11 (27%) control patients had regained 75% or more of the microbiota in their initial fecal sample.
The investigators acknowledge a few study limitations, including that it was conducted at a single institution. Therefore, they say, the findings may not apply to patients undergoing allo-HSCT at other institutions.
In addition, auto-FMT patients may have been treated previously for cancer and depleted of some good bacteria as a result of prior antibiotic therapy.
Nevertheless, the investigators believe their study demonstrated the potential of auto-FMT as a clinical intervention, “thereby reversing the disruptive effects of broad-spectrum antibiotic treatment for patients undergoing allo-HSCT transplant,” they wrote.
Lead author Ying Taur, MD, MPH, of MSKCC, and colleagues published their paper in Science Translational Medicine.
The trial, supported in part by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health, is ongoing and continues to accrue patients (NCT02269150).
“This important study suggests that clinical intervention using auto-FMT can safely reverse the disruptive effects of broad-spectrum antibiotic treatment,” said Anthony S. Fauci, MD, director of NIAID.
“If validated in larger studies, this approach may prove to be a relatively simple way to quickly restore a person’s healthy microbiome following intensive antimicrobial therapy.”