Gut Bugs in Anorexia Nervosa Trial

The Gut Bugs in Anorexia Nervosa trial was a one-arm, open-label feasibility pilot trial evaluated the tolerability and microbiological impact of encapsulated, multi-donor FMT in young women with AN (Registration: ACTRN12621001504808). The study was conducted in Auckland, New Zealand, between September 2022 and February 2024.Eighteen participants were enrolled in a capsule-delivered, multi-donor FMT intervention, with 15 completing treatment. Each participant received 20 capsules containing concentrated gut microbiota from four different donors (5 capsules per donor), taken over one or two consecutive days. No bowel cleanse was performed prior to FMT for safety reasons. Given the 18 month recruitment phase, three separate FMT treatment batches were prepared with different combinations of donor microbiota.Stool samples were collected at five time points: at enrolment (3 weeks before treatment), baseline (when treatment was administered), and 3, 6, and 12 weeks post-treatment. Stool samples were preserved in room-temperature-stable DNA/RNA Shield Fecal Collection Tubes (R1101, Zymo Research, Irvine, California, U.S.) before transfer to -80C for long-term storage. For donors, pre- and post-processing stool samples were collected at each donation and stored at -80C in DNA/RNA Shield.