To explore the signs of consistent changes of intestinal flora in type 2 diabetes mellitus (T₂DM) and diabetes kidney disease (DKD) patients, by studying the key change characteristics of intestinal flora in these patients.

Thirty patients with T₂DM,twenty-five patients with DKD were involved. Thirty healthy patients with matching age and sex were also involved as the control group. Fecal and serum specimens were collected from both the study group and the control group. High-throughput sequencing technology was used to sequence the 16S rDNA-v4 region of fecal samples; interleukin-6 (IL-6) and C-reactive protein (CRP) were detected by electrochemical luminescence and immunoturbidimetry. Microbiome analysis software QIIME (v1.9.1) was used to analyze the composition and diversity of intestinal flora. Microbial diversity analysis software LEfSe was used to compare intestinal bacteria markers differences between the study group and the healthy control group. The diagnosis model was established by the random forest method. The change characteristics of intestinal flora function were predicted by the PICRUSt.

The intestinal flora diversity of DM and DKD patients was significantly different from that of the healthy control group (P<0.05). T₂DM and DKD patients harbored lots of similar changes. For example, there was a significant decrease in Lachnospira, Faecalibacterium, Roseburia and Coprococcus(P<0.05). However, there was also a disease-specific pattern of imbalance between the two disease. There was a significant increase in Bacteroides in T₂DM patients, and in Lactobacillus, Slackia, Anaerotruncus, Haemophilus and Enterococcus in DKD patients. Functional prediction was also confirmed that T₂DM and DKD patients had more consistent changes. The correlation analysis between serum inflammatory indicators of T₂DM and DKD and bacteria suggested that the decrease of beneficial bacteria in the intestinal tract of T₂DM and DKD patients may be the cause of the increase of serum inflammatory indicators.

T₂DM and DKD patients harbored lots of similar changes in intestinal flora, a decrease of bacteria producing butyrate,but there was also a disease-specific change between the two disease,providing a data basis for further studies to evaluate the risk of nephropathy in patients with diabetes by intestinal flora.

Diabetes mellitus,type 2; Diabetic nephropathies; Gastrointestinal microbiome; DNA,ribosomal