Salivary microbiome variations in type 2 diabetes mellitus patients with different stages of periodontitis.

Background: To investigate the difference of salivary microbiome composition in type 2 diabetes mellitus with different stages of periodontitis.

Methods: 105 patients diagnosed with T2DM were divided into four groups according to the Stage of periodontitis.The 16 S rDNA hypervariable regions V3-V4 were amplified by polymerase chain reaction (PCR) after saliva DNA was extracted. The library was constructed and Illumina sequencing was performed. The sequencing results were compared with the silva 138 database, and the salivary microbiome of the four groups of patients was studied by species composition analysis, species difference analysis, principal coordinate analysis, and correlation analysis.

Results: There were significant differences in alpha diversity of salivary microbiome among the four groups, but no difference in Beta diversity. At the phylum level, there was one differential bacteria-Firmicutes, while at the genus level, there were 16 differential bacteria. Spearman's correlation analysis identified significant correlations between periodontal health indices (PLI, SBI, AL and PD) and the abundances of over 13 genera, including Streptococcus, Gemella and Capnocytophaga, etc. Additionally, the duration of diabetes exhibited a positive correlation with AL and PD.

Conclusions: There are differences in salivary microbial composition in patients with type 2 diabetes mellitus with different stages of periodontitis. There is a correlation between some saliva microbiota and periodontal inflammation.