Fecal transplants restore healthy bacteria and gut functions

Fecal microbiota transplantation is process of delivering stool bacteria from a healthy donor to a patient suffering from intestinal infection with the bacterium Clostridium difficile.

It works by restoring healthy bacteria and functioning to the recipient's gut, according to a study published this week in mBio, the online open-access journal of the American Society for Microbiology.

The study provides insight into the structural and potential metabolic changes that occur following fecal transplant, says senior author Vincent B. Young, MD, PhD, an associate professor in the Department of Internal Medicine/Infectious Diseases and the Department of Microbiology & Immunology at the University of Michigan in Ann Arbor. The transplants, which have been successful at curing more than 90 percent of recipients, have been used successfully since the 1950s, he says, though it hasn't been clear how they work to recover gut function.

"The bottom line is fecal transplants work, and not by just supplying a missing bug but a missing function being carried out by multiple organisms in the transplanted feces," Young says. "By restoring this function, C. difficile isn't allowed to grow unchecked, and the whole ecosystem is able to recover."

Young and colleagues used DNA sequencing to study the composition and structure of fecal microbiota (bacteria) in stool samples from 14 patients before and two to four weeks after fecal transplant. In 10 of the patients, researchers also compared stool samples before and after transplant to samples from their donors.

All transplant patients, treated at the Essentia Health Duluth Clinic in Minnesota, had a history of at least two recurrent C. difficile infections following an initial infection and failed antibiotic therapy.