Streptozotocin-induced T1D mice and rats showed an increased abundance of pathogenic bacteria such as Ruminococcaceae, Shigella, Enterococcus, Bacteroidaceae, and Alcaligenaceae, which may enhance insulitis through promoting the production of IL-6, IL-12, IL-17, and IFN-γ, and mediating the inflammatory response in the gut [151,153]. Here, IL17A is linked to type 1 diabetes mellitus.