Differences in foot skin microbiomes between patients with type 2 diabetes and healthy individuals

Impaired immunity and changes in the microenvironment in patients with diabetes might influence the composition of the cutaneous microbiome. However, data on the cutaneous microbiome of these patients are scarce. This study compared the fungal and bacterial components of the skin microbiome between patients with type 2 diabetes mellitus (DM) and healthy individuals. We obtained skin swab samples from the plantar forefoot of 17 patients with DM and 18 healthy individuals to conduct a cross-sectional study. The samples were profiled with culture-independent sequencing of the V3 to V4 regions of the bacterial 16S rRNA gene and the fungal ITS2 region, followed by direct DNA extraction and molecular polymerase chain reaction (PCR). We observed a differential cutaneous microbiome, especially for fungi, in patients with type 2 diabetes compared to that in healthy controls. Trichophyton rubrum was more abundant in DM samples. The Shannon diversity index for fungi was lower in the DM patients. Principal coordinate analysis plots and permutational multivariate analysis of variance (PERMANOVA) tests based on Bray-Curtis distances between samples supported the association of the fungal microbiome with DM at the species level. The results suggest that clinicians should pay attention to both fungi and bacteria and provide appropriate prevention and therapeutic strategies for diabetic cutaneous complications including diabetic foot ulcers. These data also contribute to future research associated with diabetes and cutaneous microbiomes.