Citrobacter infection may lead to loss of intestinal barrier integrity and mucosal damage by disrupting the mitochondrial structure and oxidative respiratory chain function in intestinal epithelial cells (54), accelerating insulitis via activation of diabetogenic CD8+ T cells (55) and allowing pathogens and their derived toxins to enter the bloodstream, resulting in chronic inflammation and uremia (56), which may contribute to the occurrence and development of DKD. This evidence concerns the gene CD8A and diabetic kidney disease.