RESUMEN
BACKGROUND: The skin microbiome has been implicated in the pathophysiology of atopic dermatitis (AD). Although 308 nm excimer light treatment is an effective phototherapy for AD, its effects on the skin microbiome currently remain unclear. Therefore, we investigated the effects of the excimer light treatment on the skin bacterial and fungal microbiome of lesional skin of AD. METHODS: Swab samples were collected from 11 healthy controls, non-lesional and lesional skin of 11 AD patients. The excimer light treatment was administered to the lesional skin. The composition of the skin microbiome, the clinical score and skin barrier function of the lesional skin were examined before and after the treatment. The composition of the skin microbiome was determined by sequencing bacterial 16S and fungal internal transcribed spacer regions. RESULTS: The excimer light treatment significantly changed the composition of the bacterial microbiome in the lesional skin of AD, as well as improved the clinical score and skin barrier function. The treatment increased the relative abundance of the phylum Cyanobacteria and decreased that of the phylum Bacteroidetes in lesional skin. At the species level, the treatment significantly decreased the relative abundance of Staphylococcus aureus (S aureus) in lesional skin. There was also a significant correlation between the reduction of S aureus and improvement of the clinical outcomes. CONCLUSION: Our findings suggest that alterations of the skin microbiome with excimer light treatment, specifically the decrease in the abundance of S aureus, are partly involved in the improvement of AD lesions.