Figure 1. Transition of S. pneumoniae TIGR4 deficient in polyamine transport operon (∆potABCD) from nasopharynx to lungs.

Recovery of S. pneumoniae TIGR4 or ∆potABCD (CFU/ml) from lung homogenates from C57BL/6 mice (n = 5) infected i.n. with 10⁷ CFU bacteria at [A] 4 h, [B] 12 h and [C] 24 h. Data are represented as mean ± SEM. Each datum point represents results from one animal. Mann-Whitney test was used to calculate statisical significance (**p-value = 0.008).