Phylogenetic analysis of dysbiosis in ulcerative colitis during remission.

Presence of intestinal microbes is a prerequisite for the development of ulcerative colitis (UC), although deviation of the normal intestinal microbiota composition, dysbiosis, is presumably implicated in the etiology of UC. The fecal microbiota of 30 UC samples obtained from 15 patients who were sampled twice and from 15 healthy control subjects originating from 2 geographic locations was analyzed using highly reproducible phylogenetic microarray that has the capacity for detection and quantification of more than 1000 intestinal bacteria in a wide dynamic range. The fecal microbiota composition is not significantly influenced by geographic location, age, or gender, but it differs significantly between the patients with UC and the control subjects (P = 0.0004). UC-associated microbiota is stable during remission and similar among all patients with UC. Significant reduction of bacterial diversity of members of the Clostridium cluster IV and significant reduction in the abundance of bacteria involved in butyrate and propionate metabolism, including Ruminococcus bromii et rel. Eubacterium rectale et rel., Roseburia sp., and Akkermansia sp. are markers of dysbiosis in UC. Increased abundance of (opportunistic) pathogens including Fusobacterium sp., Peptostreptococcus sp., Helicobacter sp., and Campylobacter sp. as well as Clostridium difficile were found to be associated with UC. Dysbiosis in UC is stable in time and shared between patients from different geographic locations. The microbial alterations offer a mechanistic insight into the pathogenesis of the disease.