CLINICAL EFFECTS OF FECAL MICROBIOTA TRANSPLANTATION IN DOGS WITH CHRONIC ENTEROPATHIES

Fecal microbiota transplantation (FMT) is used to transfer intestinal microbiota from a healthy donor to a recipient with gastrointestinal disease to modulate the microbiome and decrease disease activity. In people, FMT is effective in treating recurrent Clostridioides difficile infection. Repeated FMTs have also been shown to induce remission in people with ulcerative colitis in a placebo-controlled study. In dogs with chronic enteropathies (CE), a few case reports suggest decreased disease activity after FMT. The objective of this study was to report the clinical effects of FMT in a larger group of dogs with CE. Retrospective data from dogs with CE treated with FMTs as adjunctive therapy were collected. Inclusion criteria were dogs with CE not responding satisfactorily to standard treatment and for which follow-up of at least 3 months post-FMT was available. Exclusion criteria were starting a new immunosuppressive treatment, or increasing the dose of current maintenance therapy, in parallel with FMT. FMT was given as a rectal enema (5-7 g donor feces/kg body weight of recipient). Two different donors were used, both having a dysbiosis index (DI) below -2. Thirty-three dogs aged 0.6-13 years (median 6.8) were included. Dogs had been treated for CE for 1-110 months (median 21 months) at inclusion. Main presenting complaints were diarrhea (26/33) and lethargy (15/33). Thirty-two dogs were treated with corticosteroids at inclusion, and 20/33 dogs received various second line immunosuppressive drugs. Thirty-one dogs received 2-5 FMTs, with the majority (23/33) receiving 3 FMTs. Two non-responders only received one FMT each. Clinical improvement was noted in 24/33 dogs after FMT, most commonly characterized by increased activity level (18/33), improved fecal quality (17/33) and improved appetite and/or weight gain (7/33). Canine IBD Activity Index at inclusion was 2-17 (median 5), which decreased significantly to 1-9 (median 2) in the month after the last FMT (p<0.0001). Fecal samples for DI (reference interval 0) were available from 18 dogs at inclusion. Non-responders had significantly higher DI (range 0.8 to 8.9, median 4.2) compared to responders (range -2.4 to 6.0, median 0.7) (p=0.031). A high DI has been previously shown to correlate with decreased microbial diversity. In humans, low microbial diversity is a negative prognostic factor for responding to FMT, which also appeared to be the case in this group of dogs. Our results suggest that FMT can be successfully used as adjunctive therapy in dogs with CE, but prospective longitudinal studies are warranted.