Distinct bacterial facial cutaneous microbiota composition in adolescents with acne vulgaris: a population-based cross-sectional observational study.

BACKGROUND

Acne vulgaris (acne) is a prevalent dermatological condition associated with distinct facial cutaneous microbiota compositions. However, existing research often has methodological limitations such as insufficient statistical power and the under-representation of diverse adolescent populations, which are highly relevant for understanding acne pathogenesis.

OBJECTIVES

To compare bacterial facial cutaneous microbiota compositions between individuals with acne and healthy control participants in a large, multiethnic adolescent population, while adjusting for potential confounders.

METHODS

In a population-based study, we compared bacterial facial cutaneous microbiota compositions using 16S rRNA sequencing in individuals with physician-evaluated acne (n = 399) and healthy control participants (n = 527); all included individuals were adolescents (median age 13 years). We also evaluated the independent associations of biological sex, puberty stage, perceived skin colour, ethnicity and weight with facial cutaneous microbiota compositions. Our analytical approaches included the assessment of alpha and beta diversity (including permutational multivariate analysis of variance), relative abundances, univariate coordinate analysis (analysis of compositions of microbiomes with bias correction 2) and phylogenetic analyses.

RESULTS

The overall microbiota composition of individuals with acne was less rich and less diverse than that of control participants [Chao1 β -44.98 (SE 4.36), Shannon β -1.01 (SE 0.07); P < 0.01]. While acne status was a major contributor to variations in overall microbiota compositions (R2 = 4.32%, P < 0.01), skin colour, sex, puberty stage and weight also independently contributed to variations (R2 = 0.44-1.05%; P < 0.01). Specifically, individuals with acne had higher relative abundances of Cutibacterium and Staphylococcus species, and a lower abundance of Streptococcus species. Following confounder adjustment, bias correction and phylogenetic analysis, Cutibacterium granulosum, Cutibacterium acnes and Staphylococcus epidermidis emerged as the most differentially abundant species in individuals with acne vs. control participants (log fold changes = 0.75-2.17; P < 0.01).

CONCLUSIONS

Our findings reveal distinct facial microbiota compositions in adolescents with acne, identifying C. granulosum, C. acnes and S. epidermidis as a key microbial signature. This study suggests a significant clinical relevance for C. granulosum in acne pathology and a potential protective role for Streptococcus species in acne-free skin. These results underscore the importance of representative study populations in microbiome research and provide important methodological and technical insights for future investigations.