Faecal Transplantation for Ulcerative Colitis From Diet Conditioned Donors Followed by Dietary Intervention Results in Favourable Gut Microbial Profile Compared to Faecal Transplantation Alone

Abstract Background and Aims Several faecal microbial transplantation [FMT] approaches for ulcerative colitis [UC] have been investigated with conflicting results. We have recently published the clinical outcomes from the CRAFT UC Trial using FMT with the UC Exclusion Diet [UCED], compared with FMT alone. Here we aimed to compare the two FMT strategies in terms of microbial profile and function. Methods Subjects recruited to the CRAFT UC study with available pre- and post-intervention faecal samples were included. Donors received diet conditioning for 14 days based on the UCED principles. Group 1 received single FMT by colonoscopy [Day 1] and enemas [Days 2 and 14] without donors’ dietary conditioning [N = 11]. Group 2 received FMT but with donors’ dietary pre-conditioning and UCED for the patients [N = 10]. Faecal samples were assessed by DNA shotgun metagenomic sequencing. Results Following diet conditioning, donors showed depletion in metabolic pathways involved in biosynthesis of sulphur-containing amino acids. Only Group 2 showed significant shifts towards the donors’ microbial composition [ADONIS: R2 = 0.15, p = 0.008] and significantly increased Eubacterium_sp_AF228LB post-intervention [β-coefficient 2.66, 95% confidence interval 2.1–3.3, q