Comparing treatment effects on dogs with acute hemorrhagic diarrhea syndrome: fecal microbiota transplantation, symptomatic therapy, or antibiotic treatment

Objective: Dogs with acute hemorrhagic diarrhea syndrome (AHDS) present with similar clinical signs and histopathological findings as dogs with parvovirosis, in which fecal microbiota transplantation (FMT) has led to a significantly faster resolution of diarrhea and shorter hospitalization times. We investigated whether FMT results in faster clinical improvement and normalization of the intestinal microbiome compared to standard treatment. Animals: 32 client-owned dogs with AHDS. Methods: A prospective, double-anonymized clinical trial included 3 groups: symptomatic treatment (n = 12), FMT treatment (FMTT; 12), and antibiotic treatment (AT; 8). Clinical improvement was determined on the basis of AHDS index, changes in the microbiome based on the dysbiosis index, and PCR results for clostridial strains. Results: Overall, no significant differences in clinical scores between the treatment groups over time were detected except on day 2 (higher AHDS index in the AT group compared to FMTT group; P = .046). The dysbiosis index increased and P hiranonis decreased on day 1 in some dogs, but these changes were transient in the symptomatic treatment and FMTT groups. In the AT group, the dysbiosis index was persistently elevated and 4 of 8 dogs showed a reduced abundance of P hiranonis on day 42. In 67% of the dogs on day 1, NetF-encoding Clostridium perfringens was detected and enterotoxin-encoding strains increased, but these changes were transient in all dogs, regardless of therapy. Clinical relevance: Overall, in dogs with AHDS, neither FMT nor AT resulted in faster clinical improvement. In addition, C perfringens strains are self-limiting and do not require antibiotic therapy.