As shown in Figure 12A, clinically source MDR E. coli strains infection caused serious systemic inflammatory response by sharply increasing the serum proinflammatory cytokines, such as TNF-α, IFN-γ, IL-6 (P < 0.05), and a significant reduction in IL-4 levels (P < 0.05) compared with the control group. Here, IL4 is linked to infection.