FIG. 5.

YopB is essential for high levels of colonization and dissemination. BALB/c mice were infected with 300 to 500 CFU of Y. pseudotuberculosis ΔyopB grown at 26°C (•) or 37°C (▪). Mice inoculated with the ΔyopB mutant grown at 26°C were sacrificed at 1, 2, 4, 6, 7, 14, 21, 28, 35, and 42 days postinoculation, and mice inoculated with ΔyopB strain grown at 37°C were sacrificed at 1, 2, 4, 7, and 14 days postinoculation. Lungs (A), trachea (B), liver (C), and lymph nodes (D) were harvested, homogenized, and plated for CFU. Each circle represents the CFU from a mouse inoculated with the ΔyopB strain grown at 26°C, and each square represents CFU from a mouse inoculated with the ΔyopB strain grown at 37°C. Open symbols indicate that no bacteria were recovered at that limit of detection. Bars represent the geometric mean. P values were determined between the levels of the ΔyopB strain recovered as shown here and levels of wild-type Y. pseudotuberculosis shown in Fig. 2 using a two-tailed Student's t test. *, P < 0.01 between wild type and yopB mutant grown at 26°C; +, P < 0.01 between wild type and yopB mutant grown at 37°C.