FIG. 3.

Loss of htrA significantly impairs the survival of ΔprsA2 mutants in mice. Mice were injected via the tail vein with 2 × 10⁴ CFU of either the wild-type strain or ΔprsA2, ΔprsA2 plus pPL2-prsA2, ΔprsA1, ΔprsA1 ΔprsA2, ΔhtrA, ΔhtrA ΔprsA2, or ΔhtrA ΔprsA2 plus pPL2-prsA2 mutant strains. The liver and spleen of infected mice were recovered at 72 h postinoculation, and the bacterial burden in each organ was determined. A minimum of 5 mice were inoculated per strain tested, and the means and standard deviations are shown. Statistical significance was determined using one-way analysis of variance with Tukey's multiple comparison test (**, P < 0.001; ***, P < 0.0001).