FIG. 1.

Relationship between SlyA and SPI-2 in murine virulence examined by mixed infection. BALB/c mice were inoculated intraperitoneally with approximately 2 ×10⁵ CFU, and CI and COI were determined at 48 h postinoculation. Mean log₁₀ CI and COI are indicated on the y axis for the strain combinations indicated on the x axis. The error bars indicate the standard errors of the means (n = 6). Student's t test was used to test the null hypothesis that the means were equal. Confidence intervals were constructed to test the null hypothesis that the mean was 0. Three asterisks indicate that the P value is <0.001; two asterisks indicate that the P value is <0.005; and one asterisk indicates that the P value is <0.05.