Such changes in the composition of the gut microbiota, in turn, increase the level of acetic, propionic, and butyric acids in serum, regulate metabolic remodeling and macrophage gene expression network, reduce pro-inflammatory cytokines levels (TNF-α, IL-6, and IL-1β) in BALF, decrease pulmonary bacterial burdens, inflammation infiltration, and the development of MRSA-induced pneumonia (Fig. 10). Here, TNF is linked to susceptibility to pneumonia measurement.