A. Colony Forming Units (CFU) per worm growing in E. coli OP50 (white) and Salmonella Typhimurium MST1 (red) for two generations. Unpaired t-test, P < 0.0001. N = 90 worms per biological replica, each column contains three replicates. B. Percentage of L4 worms showing different phenotypes of intestinal colonization when grown on E. coli OP50-GFP and S. Typhimurium MST1-GFP. Full, partial and undetectable are defined in Procedure D. Two-way ANOVA, Holm-Sidak test, P < 0.05. N = 45 worms per biological replica.