S100A9 and infection: Compared to WT-infected mice, infection with ece1Δ/Δ and hgc1Δ/Δ strains led to lower immune activation, which was observed across all gene readouts (ece1Δ/Δ: CXCL1: 6-fold decrease; IL-6: 2-fold decrease; IL-17A: 115-fold decrease; S100A9: 30-fold decrease; and TNF: 5-fold decrease) (hgc1Δ/Δ: CXCL1: 19-fold decrease; IL-6: 14-fold decrease; IL-17A: 19-fold decrease; S100A9: 59-fold decrease; and TNF: 15-fold decrease) (Fig. 3F).