Fig 4.

Inhaled dust and exposure to high temperatures increase invasiveness of S pneumoniae in mice. Mice were colonized with S pneumoniae serotype 2 strain D39 or a Niger serotype 1 meningitis isolate (ST303) and challenged intranasally with dust at 2 and 4 days after colonization. Mice were kept at room temperature (21°C) or 40°C, as indicated for 10 minutes before and 20 minutes after infection and dust/PBS exposure. A-C, CFU per milligram of tissue in the nasopharynx (Fig 4, A), lungs (Fig 4, B), and brain (Fig 4, C) at 7 days after infection. D, Kaplan-Meier survival curve. Asterisks represent significance in 1-way ANOVA with the Dunn posttest (Fig 4, A-C) or log-rank analysis (Fig 4, D). *P < .05, **P < .01, and ***P < .001.