S. pneumoniae colonizes the nasopharynx of mice over a 6 week period. (A) Viable cell counts from head cavities (post-NALT excision) of infected mice. Open circles represent viable counts from a single mouse. Solid lines represent the geometric mean of CFUs/head for each day. Dashed line represents the limit of detection. (B) Confocal immunofluorescence image of S. pneumoniae colonizing NALT tissue 3 days post-inoculation. The green bar bell indicates the lumen of the nasopharynx, the pink bar bell indicates the epithelial monolayer, and the blue bar bell indicates the cells within the NALT. S. pnuemoniae were visualized via fluorescently-conjugated antibody (green) near the surface of the NALT (blue) and were particularly apparent in the mucus layer (red).