Mortality, bacterial burden, and cytokine kinetics in pulmonary tularemia.

<p>(A) Survival of Ft SchuS4 (10 cfu) or Ft LVS (1000 cfu) infected C57BL/6 mice (% survival of three independent experiments). (B) Lung and blood bacterial burden in Ft infection (mean ± SD of three independent experiments; the bacterial burden at all days post-infection (dpi) was significantly (p<0.001) different from the initial inoculum of 10 cfu (SchuS4) or 1000 cfu (LVS) at 0 dpi, ANOVA with Tukey’s post-test). (C) Survival with escalating Ft numbers (mean % survival of two independent experiments, Log-rank (Mantel-Cox) test, **p<0.01 and ***p<0.001 indicate difference from 10⁵−10⁷ cfu groups). (D) Cytokine and chemokine levels in lungs and (E) serum (mean ± SD of two (SchuS4, n = 6 mice) or three (LVS, n = 9 mice) independent experiments, Student’s t-test, *p<0.05 represents differences between SchuS4 and LVS strains at indicated dpi. In panels B, D and E, for SchuS4 infection at 6 dpi, ~50% of the mice had died and only the remaining live mice (n = 6) were used for analysis. As previous studies have demonstrated that most of these cytokines are significantly induced at or after 3 dpi, statistics for differences in cytokine induction at various dpi following SchuS4 or LVS infection are unmarked.