Abstract
In this study, we intend to determine the microbial communities that are differentially expressed in diabetic foot ulcers (DFUs) from the view of species abundance difference and compositions. The EMBL-EBI database and QIIME2 platform were used to obtain and process 16S rRNA sequencing data of normal healthy and DFU samples. The LEfSe software was utilised to retrieve key intestinal bacteria differentially expressed in DFUs. Additionally, PICRUSt2, FAPROTAX and BugBase functional analyses were performed to analyse the potential microbial functions and related metabolic pathways. The correlations between intestinal microbiota and clinical indexes were evaluated using the Spearman correlation analysis. Significant differences existed in intestinal microbiota between DFU and normal healthy samples regarding species abundance difference and compositions at Kingdom, Phylum, Class, Order, Family, Genus and Species levels. Seven microbiota were demonstrated differentially expressed in DFUs that contained Bacteroidaceae, Prevotellaceae, Streptococcaceae, Lactobacillales, Bacilli, Veillonellaceae and Selenomonadales. Insulin signalling pathway may be the key pathway related to the functional significance of Streptococcus and Bacillus in the DFUs. The intestinal microbiota in DFUs exhibited susceptibility to sulphur cycling while displaying pathogenic potential. Last but not least, a close relationship between Streptococcus and the occurrence of DFUs was revealed. Taken together, this study mainly demonstrated the high abundance of Streptococcus in DFUs and its correlation with the disease occurrence.