A. Comparison of major microbial populations in fecal samples. Fecal samples from uninfected (N), CR-infected (CR) and CR+DBZ-treated mice were subjected to 16S rDNA sequencing and relative abundance of phyla and families were compared. Each chart represents the taxonomic composition in the indicated groups (n = 10 mice/group). B. Principal Coordinate Analysis (PCoA) of fecal microbiome composition. While N (shown in “orange”) and CR (shown in “red”) samples grouped closer to each other, CR+DBZ samples (shown in “blue”) shifted towards the opposite ends of the coordinates revealing distinct microbial communities (p<0.001; n = 10 mice/group). C. Species identification as a potential etiologic agent. Real-time qPCR showing relative abundance for A. mucinophila in various treatment groups (p<0.005; n = 3 independent experiments). D. Fluorescence microscopy to detect bacterial invasion. The attached bacteria in the flushed colonic tissues of N, CR or CR+DBZ mice were detected by FISH using a general bacterial 16S probe (TexasRed-Eub338; Bar = 100μm; n = 10 mice/group). DAPI was used as counter-stain. E. Effect of chronic Notch inhibition on anti-bacterial peptide gene expression. qPCR to examine expression levels of antibacterial peptide genes Itln1/2, Retnlb and Ang4 encoding Intelectin-1/2, Resistin-like molecule-β and Angiogenin-4, respectively (*, **p<0.005; n = 3 independent experiments).