INS and type 2 diabetes mellitus: Significantly, levels of Lactobacillus had positive correlations with fasting glucose and glycosylated hemoglobin (HbA1c), while Clostridium was negatively associated with fasting glucose, HbA1c, plasma triglycerides, C-peptide, and insulin, suggesting that the above-mentioned species could be linked to the development of T2DM.