Next, to ask whether the reduced colonization efficiency of the polyamine mutant is involved in the induction of gut inflammation, we performed mice infection experiments with the WT or ΔspeABCEDF ΔpotAB ΔpotFGHI, respectively, and evaluated gut inflammation levels by measuring the amount of intestinal lipocalin-2 (Lcn-2), an inflammatory marker. This evidence concerns the gene LCN2 and infection.