Integrative Analysis of Fungal and Bacterial Microbiomes Across Skin, Blood, and Stool in Rosacea Patients

Rosacea is a chronic inflammatory skin disorder with multifactorial pathogenesis involving immune dysregulation and microbial alterations. This study compared the mycobiomes of skin, blood, and stool samples in rosacea patients and healthy controls to assess fungal diversity, abundance, and possible translocation, as well as associations with bacterial microbiomes. Internal transcribed spacer (ITS) region sequencing was performed on samples from 14 rosacea patients and 8 controls. While distinct fungal community compositions were observed across sample types, no significant differences in fungal diversity or genus abundance were found between the patient and control groups in any compartment. Malassezia dominated the skin mycobiome, while stool samples showed higher abundances of Candida and Saccharomyces, which were inversely correlated. Patients with high skin and blood Malassezia also exhibited increased Cutibacterium abundance, suggesting a potential role in impaired skin barrier integrity. Stool samples with elevated Saccharomyces correlated with higher levels of anti-inflammatory bacteria Prevotella and Agathobacter, whereas Candida dominance showed the opposite. These findings suggest that fungal dysbiosis, in the interplay with bacterial communities, may influence rosacea pathogenesis through the gut-skin axis. This work underscores the significance of integrated microbiome research across multiple biological compartments in order to enhance our understanding and potential targeting of microbial factors in rosacea.