We previously reported that 20% of unaffected first-degree relatives of pediatric IBD patients share the same microbial community structure (OTU-type) as IBD patients. This suggests that a preexisting dysbiosis can predispose to the development of IBD. The aims of this study were to establish that microbial community types identified in the family cohort could be reconstituted in gnotobiotic mice for further translational studies and to assess for any direct effects of this microbiota on intestinal inflammation.