FIGURE 8.

The role of LytR in nasopharyngeal colonization and systemic virulence. (A) C57BL6 mice were challenged with 10⁷ CFU S. pneumoniae D39 and pneumococci were recovered from the nasopharynx 24 or 48 h after intranasal infection of the mice. The graphs show bacterial numbers (CFUs) recovered from nasopharynx of six mice. Data are the mean (SD). ^∗∗P < 0.01; Statistical deference was determined by unpaired two-tailed Student’s t-test. (B) HE staining images of lung tissues of mice 24 h and 48 h after challenge with the indicated strains with the same challenge dose as the colonization experiments. ΔlytR-C: complemented strain. NS: Normal saline water. (C) C57BL6 mice were infected intranasally with 10⁷ cells of bacteria. Survival of the mice was recorded, and the difference in survival rates was analyzed using log-rank. ^∗∗∗P < 0.0001.