Fecal Microbiota Transplantation: From Clostridium difficile to Inflammatory Bowel Disease.

Fecal microbiota transplantation (FMT) has evolved from a case report in the medical literature to the basis of major innovations in the treatment of Clostridium difficile infection (CDI) and, potentially, inflammatory bowel disease (IBD). In the clinical setting, FMT was noted to significantly lower the risk of recurrent CDI, likely by increasing microbial diversity and altering the metabolic environment in the intestinal tract of recipients. In parallel, advances in the ability to quantify and characterize microbial communities in fecal samples led to the association of IBD with a state of intestinal dysbiosis. Consequently, a number of case series and randomized, controlled trials have evaluated FMT in treating active ulcerative colitis or Crohn's disease. Unlike in CDI, the efficacy of FMT in the treatment of IBD appears to be influenced by a number of factors, including donor microbial profiles, inflammatory burden, and the microbial diversity of the recipient. The therapeutic potential of the microbiome has led to a number of biotechnology and pharmaceutical companies isolating specific strains from healthy stool for use as targeted therapies for IBD in clinical trials. Ongoing studies are likely to determine the missing link between the efficacy of FMT and its impact on microbial communities and mucosal inflammation.