Fecal transplants restore gut microbes after antibiotics

Cancer patients who need stem cell transplants receive antibiotics that prevent life-threatening infections but can also destroy beneficial bacteria. KatarzynaBialasiewicz/iStock/Getty Images Plus

The very high doses of chemotherapy or radiation therapy that are used to treat certain cancers can destroy blood-forming stem cells in the bone marrow. Stem cell transplants can restore these cells and re-establish the bone marrow’s production of blood cells and immune function.

Stem cell recipients are given antibiotics to prevent serious bacterial infections. Evidence is mounting that the community of bacteria, or microbiota, in the gut enhance immune function and protect the body from infection. Unfortunately, antibiotics also unintentionally destroy these beneficial bacteria and thus increase the risk of life-threatening infections as well as graft-versus-host disease.

A team led by Drs. Ying Taur, Eric Pamer, and Joao Xavier of the Memorial Sloan Kettering Cancer Center tested whether the microbiota in a patient’s gut could be restored following stem cell and antibiotic treatments. Human feces contain many of the beneficial microbes from the gut. The researchers used fecal preparations that came from the patients themselves (autologous) before treatment and carried out autologously derived fecal microbiota transplantation (auto-FMT). The study was supported in part by NIH’s National Institute of Allergy and Infectious Diseases (NIAID) and National Cancer Institute (NCI). Results appeared in Science Translational Medicine on September 26, 2018.

Fecal samples were obtained from patients and frozen and stored prior to their stem cell transplantation procedure. One to five weeks later, when physicians confirmed that the transplanted stem cells had established, they assessed the patients’ beneficial gut bacteria. The first 25 patients who lacked known beneficial bacteria were enrolled in the study and randomly assigned to two different treatment groups: 14 received the autologous fecal transplant by enema and 11 received standard care.

The team found that the gut microbiota composition in 79% of the auto-FMT patients recovered to be 75% or more similar to their original gut microbe composition. In contrast, only 27% of the control patients recovered to that level. Auto-FMT restored beneficial gut bacteria within days. With standard care, beneficial gut bacteria typically take many weeks to recover from antibiotic treatment.

A genetic analysis suggested that the fecal transplant also restored gut microbe metabolic functions. The researchers are continuing to monitor the participants to assess whether auto-FMT improves patient outcomes, such as infections and graft-versus-host disease.

“This important study suggests that clinical intervention using auto-FMT can safely reverse the disruptive effects of broad-spectrum antibiotic treatment,” says NIAID Director Dr. Anthony S. Fauci. “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.”