Background & Aims Altered gut microbiota composition and function have been associated
with inflammatory bowel diseases, including ulcerative colitis (UC), but the causality and
mechanisms remain unknown. Methods We applied 16S ribosomal RNA gene sequencing,
shotgun metagenomic sequencing, in vitro functional assays, and gnotobiotic colonizations
to define the microbial composition and function in fecal samples obtained from a cohort of
healthy individuals at risk for inflammatory bowel diseases (pre-UC) who later developed …

Background Altered gut microbiota composition and function has been associated with
inflammatory bowel diseases (IBD) including ulcerative colitis (UC), but causality and
mechanisms remain unknown. Most studies have examined patients with active or treated
disease and little is known about microbial compositional or functional changes that occur
before disease onset. Aims We studied a longitudinal cohort of subjects at risk for IBD to
define the fecal microbial composition and function in subjects prior to UC onset (pre-UC) …