IL-1 signaling is required for control of bacterial burden in blood, liver and spleen only for S. suis P1/7 strain. Bacterial burden in blood (A, B), liver (C, D) and spleen (E, F) of wild-type (WT) and IL-1R−/− mice infected with strain P1/7 or SC84 12 h (left panels) or 48 h (right panels) post-infection. A blood bacterial burden of 2 × 109 CFU/mL, corresponding to the average burden upon euthanasia, was attributed to euthanized mice. Data represent the geometric mean (n = 6). *(p < 0.05) indicates a significant difference between WT and IL-1R−/− mice.