Characterization and Analysis of the Skin Microbiota in Rosacea: A Case–Control Study

Background: The efficacy of antibiotics in rosacea treatment suggests a role for microorganisms in its pathophysiology. Growing concern over the adverse effects of antibiotic use presents a need for targeted antimicrobial treatment in rosacea. Objective: We performed a case–control study to investigate the skin microbiota in patients with rosacea compared to controls matched by age, sex, and race. Methods: Nineteen participants with rosacea, erythematotelangiectatic, papulopustular, or both, were matched to 19 rosacea-free controls. DNA was extracted from skin swabs of the nose and bilateral cheeks of participants. Sequencing of the V3V4 region of the bacterial 16S ribosomal RNA gene was performed using Illumina MiSeq and analyzed using QIIME/MetaStats 2.0 software. Results: Compared with controls, skin microbiota in erythematotelangiectatic rosacea was depleted in Roseomonas mucosa (p = 0.004). Papulopustular rosacea was enriched in Campylobacter ureolyticus (p = 0.001), Corynebacterium kroppenstedtii (p = 0.008), and the oral flora Prevotella intermedia (p = 0.001). The highest relative abundance of C. kroppenstedtii was observed in patients with both erythematotelangiectatic and papulopustular rosacea (19.2%), followed by papulopustular (5.06%) and erythematotelangiectatic (1.21%) rosacea. C. kroppenstedtii was also associated with more extensive disease, with the highest relative abundance in rosacea affecting both the cheeks and nose (2.82%), followed by rosacea sparing the nose (1.93%), and controls (0.19%). Conclusions: The skin microbiota in individuals with rosacea displays changes from that of healthy skin, suggesting that further studies examining a potential role for the skin microbiota in the pathophysiology of rosacea may be warranted.