FIG 6.

Virulence phenotype of rafR exchange mutants. Groups of 16 mice were infected intranasally with 10⁸ CFU of the indicated strain. At 24 h, all mice from each group were euthanized and numbers of pneumococci in the indicated tissues/sites were quantitated (see Materials and Methods). Viable counts (total CFU per tissue) are shown for each mouse at each site; horizontal bars indicate the geometric mean (GM) CFU for each group; the broken line indicates the threshold for detection. Differences in GM bacterial loads between groups are indicated by asterisks: *, P < 0.05, **, P < 0.01, and ****, P < 0.0001, by unpaired t test.