On the one hand, Staphylococcus aureus and Pseudomonas aeruginosa activate the transcription of IL-1, IL-6, and TNF-α when incubated with peripheral blood monocytes; endotoxin-free E. coli induces the production of IFN-γ and Lactobacillus and Bacteroides aggravate colitis via IFN-γ through toll-like receptor 9. Here, IFNG is linked to colitis.