A pilot study investigating the bacterial and fungal community shifts in facial skin in rosacea

Objective This study aimed to characterize the bacterial and fungal communities in the facial skin of patients with rosacea versus healthy controls and assess their association with skin oil content. Methods In this prospective observational study, facial skin samples from eight individuals (six patients with rosacea and two healthy controls) across three skin oil types were analyzed using 16S rRNA and internal transcribed spacer sequencing. Analyses included alpha/beta diversity, compositional profiling, and cross-kingdom correlations. Results Patients with rosacea exhibited higher bacterial diversity (Shannon index: 2.26 ± 1.12) than controls (0.71 ± 0.07). Fungal communities underwent extreme restructuring with near-complete species replacement between individuals (Bray–Curtis ∼1.0). Skin oil content was a key determinant of microbial diversity. Cross-kingdom bacteria–fungi correlations were weak and nonsignificant. Conclusions Rosacea is associated with distinctive cross-kingdom microbiome alterations, featuring increased bacterial diversity and profound fungal reorganization. These findings challenge prevailing dysbiosis paradigms and highlight the potential for therapeutic strategies targeting both bacterial and fungal elements.