Gaps in knowledge and future directions for the use of faecal microbiota transplant in the treatment of inflammatory bowel disease

Faecal microbiota transplant (FMT) has now been established into clinical guidelines for the treatment of recurrent and refractory Clostridioides difficile infection (CDI). Its therapeutic application in inflammatory bowel disease (IBD) is currently at an early stage. To date there have been four randomised controlled trials for FMT in IBD and a multitude of observational studies. However significant gaps in our knowledge regarding optimum methods for FMT preparation, technical and logistics of its administration, as well as mechanistic underpinnings, still remain. This article aims to highlight these gaps by reviewing evidence and makes key recommendations on the direction of future studies in this field. In addition, we provide an overview of the current evidence of potential mechanistics of FMT in IBD