The Fecal Microbiome in Dogs with Acute Diarrhea and Idiopathic Inflammatory Bowel Disease

Abstract

BackgroundRecent molecular studies have revealed a highly complex bacterial assembly in the canine intestinal tract. There is mounting evidence that microbes play an important role in the pathogenesis of acute and chronic enteropathies of dogs, including idiopathic inflammatory bowel disease (IBD). The aim of this study was to characterize the bacterial microbiota in dogs with various gastrointestinal disorders.Methodology/Principal FindingsFecal samples from healthy dogs (n = 32), dogs with acute non-hemorrhagic diarrhea (NHD; n = 12), dogs with acute hemorrhagic diarrhea (AHD; n = 13), and dogs with active (n = 9) and therapeutically controlled idiopathic IBD (n = 10) were analyzed by 454-pyrosequencing of the 16S rRNA gene and qPCR assays. Dogs with acute diarrhea, especially those with AHD, had the most profound alterations in their microbiome, as significant separations were observed on PCoA plots of unweighted Unifrac distances. Dogs with AHD had significant decreases in Blautia, Ruminococcaceae including Faecalibacterium, and Turicibacter spp., and significant increases in genus Sutterella and Clostridium perfringens when compared to healthy dogs. No significant separation on PCoA plots was observed for the dogs with IBD. Faecalibacterium spp. and Fusobacteria were, however, decreased in the dogs with clinically active IBD, but increased during time periods of clinically insignificant IBD, as defined by a clinical IBD activity index (CIBDAI).ConclusionsResults of this study revealed a bacterial dysbiosis in fecal samples of dogs with various GI disorders. The observed changes in the microbiome differed between acute and chronic disease states. The bacterial groups that were commonly decreased during diarrhea are considered to be important short-chain fatty acid producers and may be important for canine intestinal health. Future studies should correlate these observed phylogenetic differences with functional changes in the intestinal microbiome of dogs with defined disease phenotypes.

Effect of an extruded animal protein‐free diet on fecal microbiota of dogs with food‐responsive enteropathy

“…These findings are similar to those of previous studies, where lower bacterial diversity and richness and different microbial communities in dogs with acute and chronic GI disease compared to those in HC dogs were reported 16, 18, 41, 42, 43, 44. At the phylum level, an increased abundance of Proteobacteria was detected, based on the univariate analyses.…”

“…Several studies have evaluated how to modulate the intestinal microbiota in dogs with GI diseases. In dogs with IBD, previous reports showed no changes in fecal microbiota after treatment with immunosuppressive drugs 16, 18, 43. In dogs with acute diarrhea, after perturbation the microbiota seemed to return to the starting condition 45.…”

“…In IBD dogs, instead, an on‐going chronic pathological process is suspected to remain after improvement of the clinical signs. Secondly, the follow‐up samples were collected after a shorter16 or equal18, 43 period in previous studies of IBD dogs. Therefore, the length of the time of follow‐up sampling may be sufficient to recover from FRE, but not from IBD.…”

“…, Streptococcus spp. , E. coli, Blautia spp., Fusobacterium spp., Clostridium Hiranonis )33 in the fecal microbiota were analyzed by qPCR assays, as described previously for canine fecal samples 18, 34…”

“…Studies in veterinary species have associated intestinal dysbiosis with various GI disorders, such as acute diarrhea, CE (eg, inflammatory bowel disease [IBD]), granulomatous colitis and colorectal polyps 12, 15, 16, 17, 18. Although a relationship exists between the gut microbiota and these diseases, it is unclear, in most cases, if alterations in the microbiota are a cause or an effect of the disease and whether manipulation of the gut microbiota could help to prevent or even treat the disease 13, 19…”