Characterization of the facial microbiome in twins discordant for rosacea

Abstract

Previously, we determined that genetic and environmental factors contributed equally towards rosacea in twins. To assess an environmental factor, we characterized the malar cheek bacterial microbiome from twins discordant for rosacea. We found no significant difference in facial microbiome alpha and beta diversity between related twins discordant for rosacea. However, the relative percentage abundance of Gordonia and Geobacillus, low-abundant genera, was positively and negatively associated with rosacea severity, respectively. Our data demonstrate a significant correlation between facial microbiome and severity of rosacea in genetically matched twins and importantly that overall microbiome composition is largely unchanged. | BACKG ROU N DRosacea is a chronic inflammatory disease of the facial skin and eyes that affects ~16 million individuals in the United States alone.Although its aetiology is unknown, we previously determined that both genetic and environmental factors contribute equally towards disease using identical (monozygotic) and fraternal (dizygotic) twins. [1] Previous studies have implicated microbial colonization and the cognate immune response as the critical driver of rosacea. [2,3] Increased levels of Demodex mites and associated bacteria (bacillus), antimicrobial peptides (eg cathelicidin/LL37), host immune variables (eg Tolllike receptor (TLR)-2) and nutrients (eg vitamin D3) are reported to alter the innate immune response and cause chronic inflammation and the facial skin sensitivity in rosacea. [2,3] In addition, the recent studies suggest significant associations between the severity of rosacea and systemic comorbidities (eg cardiovascular, allergic, respiratory, metabolic and gastrointestinal diseases) that are linked with chronic inflammation. [4,5] Rosacea and its reported comorbidities share involvement with barrier tissues that are colonized with a wide variety of microflora that constitute the microbiome. | QUE S TION ADDRE SS EDThe beneficial use of therapeutic drugs for rosacea including oral and topical antibiotics, sulphur compounds and ivermectin that alter the facial microbiome, [6] suggests that altering the resident skin microbiome may play a role in the disease. However, no conclusive evidence has been established.Microbial dysbiosis could be one of the factors associated with the pathogenesis of rosacea as well as its comorbidities. Harnessing the genetic and environmental control inherent in a twin study, we performed next-generation sequencing of the 16S rRNA gene to evaluate the hypothesis that facial bacterial microbiome dysbiosis will associate with the severity of rosacea in twins discordant for rosacea. | E XPERIMENTAL DE S I G NSee Appendix S1. | RE SULTS | Comparable overall facial skin microbiome composition across subjectsWe estimated the relative percentage abundance (RPA) of facial bacterial microbiome at the phylum level in twins with and without rosacea. The top four abundant phyla were Firmicutes (mean ± SD; 42.98% ± 1.05%), Proteobacteria (39.29% ± 1...

Characterization and Analysis of the Skin Microbiota in Rosacea: Impact of Systemic Antibiotics

“…However, one should carefully interpret its increase as Weissella confusa has also been associated with sepsis and other serious infections in humans [36]. In fact, the abundance of Weissella genera showed positive correlation with rosacea severity in a twin study [27] (univariate random effect Poisson regression), which contradicts our findings.…”

“…Our longitudinal cohort study examined the skin microbiota of untreated patients and the influence of systemic antibiotics on the skin microbiota. Through 16s rRNA gene sequencing, we found S. epidermidis and C. acnes to be prevalent in the untreated rosacea skin samples, consistent with prior findings [27][28][29][30]. Present in healthy and diseased skin, their roles as commensals or opportunistic organisms are not completely understood.…”

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Coupled blue and red light-emitting diodes therapy efficacy in patients with rosacea: two case reports

“…More recently, in a NRS-supported study in twins, Zaidi and colleagues [24] reported the first evidence highlighting the correlation between the severity of rosacea and microbial dysbiosis on the skin, but further study is needed to determine the species involved.…”