Alterations of the colonic microbiota in response to osmotic diarrhea

Diseases of the human gastrointestinal (GI) tract are often accompanied by diarrhea and these diseases show often profound alterations of the GI microbiota termed dysbiosis. Whether dysbiosis originates from the disease itself or from the accompanying diarrhea remains elusive. With this study we characterized for the first time the net-effects of osmotic diarrhea on the composition of the GI microbiota in the absence of disease. We induced osmotic diarrhea in four healthy adults by oral administration of polyethylene-glycol 4000 (PEG). Stool as well as mucosa specimens were collected before, during and after diarrhea and 16S rDNA-based microbial community profiling was used to assess the microbial community structure. Stool and mucosal microbiotas were strikingly different wherein Firmicutes dominated the mucosa and Bacteroidetes stools. Compared to stools a higher phylotype richness was noted on the mucosa. Osmotic diarrhea led to a significantly decreased phylotype richness and to a prominent equalization of the otherwise individualized microbiotas on the mucosa. Moreover, diarrhea lead significant shifts in the phyla Bacteroidetes and Firmicutes and importantly to an increased abundance of Proteobacteria on the mucosa, a phenomenon also noted in several inflammatory and diarrheal GI diseases. Sample description: Barcode Sample Individual Timepoint Type Run AGCAGC AF1 A 1 (pre diarrhea) Feces FJC1PKF02.sff CTCAGC AF2 A 2 (pre diarrhea) Feces FJC1PKF02.sff TGCGAT AF3 A 3 (diarrhea) Feces FJC1PKF02.sff AGATGC AF4 A 4 (post diarrhea) Feces FJC1PKF02.sff ATGATG BF1 B 1 (pre diarrhea) Feces FJC1PKF02.sff ATGCAG BF2 B 2 (pre diarrhea) Feces FJC1PKF02.sff ATGCTC BF3 B 3 (diarrhea) Feces FJC1PKF02.sff CAGAGC BF4 B 4 (post diarrhea) Feces FJC1PKF02.sff AGCATG CF1 C 1 (pre diarrhea) Feces FJC1PKF02.sff ATCATC CF2 C 2 (pre diarrhea) Feces FJC1PKF02.sff ATCTGC CF3 C 3 (diarrhea) Feces FJC1PKF02.sff ATGAGC CF4 C 4 (post diarrhea) Feces FJC1PKF02.sff CAGATG DF1 D 1 (pre diarrhea) Feces FJC1PKF02.sff CAGCAG DF2 D 2 (pre diarrhea) Feces FJC1PKF02.sff CAGCTC DF3 D 3 (diarrhea) Feces FJC1PKF02.sff CATCTG DF4 D 4 (post diarrhea) Feces FJC1PKF02.sff CAGCTC BM2 B 2 (pre diarrhea) Mucosa FS0825402.sff CATCTG BM3 B 3 (diarrhea) Mucosa FS0825402.sff CTGATC CM2 C 2 (pre diarrhea) Mucosa FS0825402.sff CTGCTG CM3 C 3 (diarrhea) Mucosa FS0825402.sff CATGAG DM2 D 2 (pre diarrhea) Mucosa FS0825402.sff CTCATG DM3 D 3 (diarrhea) Mucosa FS0825402.sff