We highlighted statistically significant (P < 0.05) differentially abundant pathways of intestinal bacterial genes that discriminate between groups of patients with iDFUs, including “type I diabetes mellitus” and “type II diabetes mellitus” pathways, “insulin signaling pathway”, “beta-lactam resistance”, “glycolysis/glucogenesis pathway”, “glyoxylate and dicarboxylate metabolism”, “starch and sucrose metabolism”, “valine, leucine and isoleucine biosynthesis”, and “peptidoglycan biosynthesis”, “lipopolysaccharide biosynthesis”. Here, INS is linked to type 1 diabetes mellitus.