In addition to metformin, Sato et al. report significantly higher abundance of Lactobacillus in fecal samples from Japanese T2DM patients treated with sulfonylurea (SU), α-glucosidase inhibitors (α-GI), thiazolidine, dipeptidyl peptidase-4 (DPP-4), GLP-1 receptor agonist and insulin with oral therapy, compared to control subjects [164]. Here, DPP4 is linked to type 2 diabetes mellitus.