Impact of capsular types on pneumococcal clearance rate in the bloodstream. (A–C) Bacteremia kinetics in the first 30 min (A), proportional distribution at 5 min (B), and bacterial viability at 30 min (C) after i.v. infection of CD1 mice with 108 CFU of acapular (Δcps) and serotype-14 derivatives of TH870 (Spn14). n = 3. (D–F) Bacteria in the bloodstream of CD1 mice infected i.v. with 103–107 CFU in the first 30 min. Data are presented as bacteremia kinetics of serotypes 14 (D) and 3 (E) or CT50 (F). n = 3–6. (G) Ranking of 15 pneumococcal serotypes based on the CT50 values of isogenic capsule-switched derivatives of TH870 in CD1 mice infected i.v. with 106 CFU. n = 5–6. CT50 was calculated by nonlinear regression of bacteremia data, which is presented as 30 min when >50 of the inoculum was still detectable in the circulation. Data were from one experiment (A–C) or pooled from two independent experiments (D–G). Two-way ANOVA with Tukey’s multiple comparisons test (A), unpaired t test (C), ***, P < 0.001, ****, P < 0.0001.
