DOI: 10.4103/bbrj.bbrj_50_26 ISSN: 2588-9834

A Novel Functional Gradient and Multilayered Dysbiosis in Facial Seborrheic Dermatitis: New Insights from Shotgun Metagenomics

Kim-Thoai Tran, Gia-Thinh Nguyen, Huyen-Trang Vu
Show PDF Cite

Background:

Seborrheic dermatitis (SD) is a chronic inflammatory dermatosis affecting approximately 5% of the global population; however, diagnosis relies entirely on clinical assessment without objective laboratory confirmation. We evaluated shotgun metagenomics as a laboratory tool for characterizing skin microbiome dysbiosis in SD, with emphasis on diagnostic performance, antimicrobial resistance (AMR) profiling, and clinical utility for treatment guidance.

Methods:

This cross-sectional study analyzed 115 facial skin samples from 78 Vietnamese participants (38 SD patients and 40 healthy controls) using shotgun metagenomics. We performed taxonomic profiling, functional pathway analysis, AMR gene detection, and virulence factor identification. Random Forest classification evaluated diagnostic accuracy, while MaAsLin2 identified severity-associated biomarkers.

Results:

We discovered a novel three-phase functional gradient (Control → Non-SD peak → SD decline) suggesting a “biological alert state” in clinically unaffected skin. Malassezia restricta dominated SD lesions (90.92% vs. 81.87%; P < 0.001) with 53.5% reduction in fungal richness. Bacterial profiling revealed Staphylococcus epidermidis expansion and aerobic-to-anaerobic community transition. AMR profiling demonstrated selective enrichment of fusB (fusidic acid resistance) and blaR1 (beta-lactam sensing), providing treatment guidance. The virulence factor iron-regulated surface determinant E showed significant severity association ( q = 6.83 × 10 −3 ). Diagnostic accuracy reached 75.64% (bacterial) and 66.67% (fungal profiles).

Conclusion:

This first Vietnamese shotgun metagenomic study reveals multilayered dysbiosis encompassing taxonomic, functional, AMR, and virulence dimensions in facial SD. The novel functional gradient offers early detection potential, while population-specific AMR profiles support personalized antimicrobial therapy selection. These findings substantially advance understanding of SD pathogenesis beyond previous amplicon-based studies.

More from our Archive