MPO and infection: Considering that macrophages and neutrophils are the two most important immune cells involved in the formation of liver abscesses, we compared the distribution of F4/80+ and MPO+ cells between the healthy control group, hvKP infection group, classical KP (cKP) infection group (low-virulence), hvKP infection group after macrophage depletion, and NMN + antibiotics group using immunohistochemistry (Fig. 5A and B).