Figure 1. Type 1 and F17-like pili promote UPEC intestinal colonization.

Streptomycin pretreated C3H/HeN mice were concurrently (a–j) or singly (k) colonized with WT UTI89 and/or UTI89 lacking one or more CUP operons. (l,m) Purified adhesin lectin domains FimH^LD (type 1 pili) and UclD^LD (F17-like pili) were tested for binding to mouse colonic sections. Sections were stained with hoechst (blue) and antibodies to Muc2, a mucus-associated glycoprotein (green). FimH^LD and UclD^LD binding was lost by pre-treating tissue sections with PNGase and O-glycosidase, respectively. Arrowheads highlight binding by FimH^LD or UclD^LD. (n) UclD^LD does not bind five common monosaccharides. Ce=cecum, Col=colon, CI=competitive index. Bars represent mean values ± SEM (a–j, n), geometric means ± SD (k). *p<0.05, **p<0.01, ***p<0.001 by Wilcoxon Signed Ranked (a–j) or Mann Whitney U test (k,n). n=5 mice, 1 replicate (a, d–g). n=10 mice, 2 replicates (b,h). n=6 mice, 1 replicate (c). n=14 mice, 3 replicates (i). n=8, 2 replicates (j). n=12 mice, 3 replicates (UTI89); n=9 mice, 2 replicates (UTI89Δfim); n=15 mice, 3 replicates (UTI89Δucl); n=10 mice, 2 replicates (UTI89ΔfimΔucl) (k). Replicates are biological (a–k). n=3 tissue sections, 4 represenative images per section (l,m). n=3 wells, 3 technical replicates (n).