eutE inactivation in UPEC strain U1 abolishes ethanolamine growth stimulation in AUM, despite preserved ethanolamine catabolism. (A) Growth of U1, the U1 ΔeutB mutant, and the complemented strain in modified M9 plus 10 mM ethanolamine. (B) Growth of U1, the U1 ΔeutE mutant, and the complemented strain in modified M9 with 10 mM ethanolamine. (C) Growth of U1, the U1 ΔeutB mutant, and the complemented strain in AUM plus 10 mM ethanolamine. (D) Growth of U1, the U1 ΔeutE mutant, and the complemented strain in AUM with 10 mM ethanolamine. In panels A to D, the growth of U1 in control medium without ethanolamine (No EA or 0 mM Eth) is shown as open circles. (E) Percent change in ethanolamine concentration measured by HPLC over 24 h of U1, U1 ΔeutB, U1 ΔeutE, and their complemented strains in AUM with an initial 10 mM ethanolamine. ***, significant difference from the wild type (P < 0.001, 1-way analysis of variance). All values are the mean ± SEM (n = 3).