A recent study revealed significant differences in the skin microbiome between patients with early-stage acne and those without acne.
In the study, published in the Journal of the European Academy of Dermatology and Venereology, researchers found reduced bacterial diversity and altered species composition in the nonlesional forehead skin areas of patients who had mild-to-moderate acne compared with patients who didn't have acne.
The researchers analyzed the skin swab samples from 51 participants (30 with mild-to-moderate acne and 21 without acne) aged 12 to 35 years. Using high-throughput sequencing of bacterial 16S rRNA, Staphylococcus tuf gene fragments and fungal ITS1 regions, they compared the relative abundance, alpha-diversity, and beta-diversity of microbial communities between the two groups.
The patients had a mean age of 21 ± 2 years in the nonacne group and 21 ± 1 years in the acne group. Gender distribution was 10 females and 11 males in the nonacne group and 27 females and 3 males in the acne group. Skin phototypes were predominantly III and IV in both groups. In the acne group, 67% had mixed skin type. Acne severity was assessed using the Global Evaluation of Acne (GEA) scale, with patients who had acne having mild-to-moderate acne (Grade 2 or 3).
Researchers collected swab samples from a 2 x 5 cm forehead area, avoiding papules and pustules in the patients with acne. Saline-soaked sterile cotton swabs were used to rub the skin for 30 seconds. Samples were stored at –80°C prior to DNA extraction.
DNA extraction was performed using a QIAcube instrument for automated two-step extraction. High-throughput sequencing was conducted using an Illumina Miseq system. Specific gene regions sequenced included V1–V3 of 16S rRNA for bacterial identification, tuf gene fragment for Staphylococcus species identification, and ITS1 region for fungal identification.
Bioinformatic analysis employed Mothur software, using Greengenes database for bacteria, GenBank for Staphylococcus, and Findley ITS for fungi.
Among the key findings were:
- Higher abundance of Cutibacterium in acne subjects (72.4% vs 57.8% in patients without acne)
- Lower abundances of Corynebacterium (2.8% vs 4.8%) and Streptococcus (1.4% vs 3.2%) in patients with acne
- Significantly lower bacterial alpha-diversity indices in patients with acne, indicating reduced richness and evenness
- Significant differences in bacterial beta-diversity indices between groups
- Altered Staphylococcus species profiles, with S. epidermidis predominant in patients with acne (44.2%) and S. capitis in patients without acne (46.7%)
- No statistically significant differences in fungal communities, with Malasseziales order dominant in both groups.
Analysis of 1,915 operational taxonomic units (OTUs) revealed significant differences in bacterial populations. Alpha-diversity indices showed lower richness and evenness in the patients with acne:
- Observed OTUs: P = .058
- Chao1: P = .044
- Shannon: P = .030
- Inv-Simpson: P = .041.
Beta-diversity indices also differed significantly:
- Jaccard: P = .023
- Bray-Curtis: P = .033
- Unweighted UniFrac: P = .038
- Weighted UniFrac: P = .088.
Among 29 Staphylococcus species analyzed, overall abundance was 14.5% in the patients without acne vs 12.0% in the patients with acne. Alpha-diversity indices for Staphylococcus species showed significant differences:
- Observed OTUs: P = .024
- Chao1: P = .024
- Shannon: P = .016
- Inv-Simpson: P = .015.
Beta-diversity indices for Staphylococcus species also differed significantly:
- Jaccard: P = .014
- Bray-Curtis: P = .015
- Unweighted UniFrac: P = .015
- Weighted UniFrac: P = .044.
Analysis of 869 OTUs from 50 samples (one patient with acne was excluded because of low sequencing depth) showed no statistically significant differences between both groups. Cumulative relative frequencies of Malasseziales were 80.0% in the nonacne group vs 85.6% in the acne group. Alpha-diversity indices for fungal populations showed a trend towards reduced richness and evenness in the patients with acne, but the differences were not statistically significant:
- Observed OTUs: P = .056
- Chao1: P = .119
- Shannon: P = .107
- Inv-Simpson: P = .117.
The researchers observed that the overall abundance, richness, and evenness of bacterial populations were lower in the patients with acne. Hierarchical clustering based on the Jaccard index revealed distinct groupings of acne and nonacne groups for both overall bacterial populations and Staphylococcus species.
The researchers suggested that this early-stage dysbiosis may contribute to the onset of acne lesions. They proposed that antiacne strategies could focus on rebalancing the skin microbiota, potentially through the use of topical products that selectively target acne-associated bacterial species while preserving less abundant bacteria.
This findings provided valuable insights into the microbiome changes occurring during early acne emergence. The findings may inform the development of new preventive and therapeutic approaches for acne management, emphasizing the importance of maintaining microbial diversity and balance in facial skin.
The researchers acknowledged the need for further multi-omics investigations to gain a more comprehensive understanding of early-stage acne dysbiosis and to evaluate the effects of microbiome-targeted interventions.
Conflict of interest declarations can be found in the study.