Culture characterization of the skin microbiome in Type 2 diabetes mellitus: A focus on the role of innate immunity.

Aims: The current study aimed at determining the differences between the cutaneous microbial flora of patients with Type 2 diabetes mellitus (T2DM) and those without, and thus evaluate for cutaneous microbiome dysbiosis in diabetes.

Methods: We employed a case-control study design with 41 participants in each group. The skin over the toe-web space was swabbed and cultured aerobically. Data was analyzed for differences in microbial prevalences and growths between the two groups. Predictors for heavy colonization by microbes were analysed using logistic regression.

Results: We found significantly higher prevalences of Staphylococcus epidermidis among patients with T2DM (77.5% vs. 53.7%, p=0.02). Further, when prevalent, these bacteria showed a significantly greater degree of skin colonization i.e. CFUs/cm among these patients, p=0.03. Highly pathogenic bacteria such as S. aureus were more prevalent among patients with T2DM. The regression model determined a significant association between T2DM status and heavy colonization by S. epidermidis (OR - 5.40, p=0.02). Also, agricultural workers were significantly more likely to have heavy colonization by S. epidermidis (OR - 3.75, p=0.02). Other predictor variables did not show significant association with heavy colonization by any of the isolated microbes.

Conclusions: Our findings support the existence of cutaneous microbiome dysbiosis among patients with T2DM. Literature suggests that microbiome dybiosis in T2DM could stem from the same activated innate immune response that is thought to be central to the development of T2DM. This dysbiosis could increase the risk of developing skin infections.