Clinical benefit of faecal microbiota transplantation administered <i>via</i> a single retention enema as an adjunctive treatment in dogs with chronic enteropathy: a randomised controlled trial

OBJECTIVES: To evaluate the clinical benefit of faecal microbiota transplantation administered via a single retention enema, as an adjunctive treatment in the management of dogs with chronic enteropathy. MATERIALS AND METHODS: Blinded, randomised controlled trial. Dogs with chronic enteropathy (>3 weeks of small or mixed intestinal diarrhoea) were randomly allocated to either the faecal microbiota transplantation or standard treatment group (ratio 1:1) via blinded selection. Dogs in the standard treatment group had a diet change only, while dogs in the faecal microbiota transplantation group had a diet change and faecal microbiota transplantation. faecal microbiota transplantation was performed using fresh faecal material from donor dogs, screened for selected enteropathogens and administered via retention rectal enema. Outcomes measured included the Canine Inflammatory Bowel Disease Activity Index, faecal score and the owner's reported improvement. Group comparisons were made using Fisher's exact tests (owner-reported outcomes) and Kruskal-Wallis tests adjusted for ties (Canine Inflammatory Bowel Disease Activity Index and faecal score). RESULTS: Forty-two dogs with chronic enteropathy (median Canine Inflammatory Bowel Disease Activity Index score 6 [range 4 to 11]) were included in the study. Twenty-five dogs were randomly assigned to receive faecal microbiota transplantation, while 17 dogs were allocated to standard treatment. A progressive improvement in stool consistency (reduced faecal score) was recorded over time for most dogs in both groups. By Day 90, the rates of owner-defined clinical improvement were 76% (CI 54% to 90%) in the faecal microbiota transplantation group and 73% (CI 40% to 92%) in the standard treatment group. No significant differences were evident between the two groups based on the proportion of owners that reported clinical improvement, Canine Inflammatory Bowel Disease Activity Index score or faecal score. CLINICAL SIGNIFICANCE: This study did not demonstrate a clear clinical benefit for adjunctive faecal microbiota transplantation via single retention enema in dogs with chronic enteropathy compared to diet change alone, although the small sample size means that a type II error cannot be excluded. The similar outcome for both groups supports high rates of food responsiveness among this cohort of chronic enteropathy dogs.