To analyze the ecological characteristics of intestinal flora in patients with diabetes nephropathy (DKD), and explore the correlation between the ecological characteristics of intestinal flora and gastrointestinal dysfunction.

A total of 150 patients with DKD admitted to Wuxi Xishan People's Hospital from March 2021 to March 2023 were selected and included in the DKD group, and 80 patients with type 2 diabetes mellitus (T2DM) were selected and included in the T2DM group. Fresh fecal samples were collected from patients, 16sRNA detection was performed, and the differences in gut microbiota composition, abundance, and diversity were compared between the two groups. According to the presence or absence of gastrointestinal dysfunction symptoms in DKD group patients, they were separately included in the functional impairment group and the non impairment functional group. The characteristics of gut microbiota in the two subgroups were compared, and the association between DKD and gastrointestinal dysfunction and the ecological characteristics of gut microbiota was analyzed.

The α diversity analysis results indicated that the Chao index of the DKD group was significantly higher than that of the T2DM group, and the Shannon index was significantly lower than that of the T2DM group, with statistically significant difference (P<0.05). The β diversity principal component analysis showed that there were differences in the gut microbiota structure between the DKD group and the T2DM group (P<0.05). At the phylum level, the relative abundance of Firmicutes in the DKD group was lower, while the relative abundance of Proteobacteria was higher. At the genus level, the relative abundance of Escherichia Shigella in the DKD group increased, while the relative abundance of Blautia and Bacteroides decreased. Among 150 DKD patients, 103 (68.67%) had gastrointestinal dysfunction symptoms. In terms of relative abundance levels of Firmicutes, the functional impairment group was lower than the T2DM group and the non functional impairment group. In terms of the relative abundance level of Proteobacteria, the functional impairment group was higher than the T2DM group and the non functional impairment group, with statistically significant differences (P<0.01). Firmicutes in the functional impairment group was positive correlated with hypersensitive C-reactive protein and interleukin-6, while Proteobacteria was negatively correlated with hypersensitive C-reactive protein and interleukin-6 (P<0.05).

The diversity and abundance of pathogenic bacteria in patients with diabetes nephropathy are increased, while the diversity and abundance of beneficial bacteria are decreased. Gastrointestinal dysfunction in patients with diabetes nephropathy may be related to the decrease of the relative abundance of Firmicutes and the increase of the relative abundance of Proteobacteria.