Figure 4.

TheiutAmutant is outcompeted byE. coliO104:H4 strain C3493 in the murine intestine. Female ICR mice were intragastrically inoculated with 1:1 mixtures of (A) E. coli O104:H4 strain C3493 and its isogenic iutA mutant CSS001. Animals were euthanized at 24, 48, 72, 96 and 168 h, and the number of colonies recovered from the cecum and counted on antibiotic-containing media was used to calculate the competition index (CI). The CI is the ratio of mutant to wild-type CFU in output samples/mutant to wild type CFU in the inoculum. A CI value of 1 (shown by the black line) indicates that the mutant competes equally with the wild-type strain. Bars represent the geometric mean with the 95% confidence interval. The CIs of samples from the same intestinal site were compared by the Mann Whitney non-parametric test.