Supplementary Material for: Cheek Microbial Communities Vary in Young Children with Atopic Dermatitis in China

Background: Atopic dermatitis (AD) is a chronic, recurrent skin condition with recently increased incidence in younger children. AD development has been correlated with the skin microbiome, and Staphylococcus aureus enrichment causes significant increases in skin lesions. Objective: Our objectives were to compare the microbial diversity of the cheek skin of children with or without AD aged 0–1 years in China, and to determine whether 4 types of skin-isolated bacteria could inhibit S. aureus in vitro. Methods: The skin microbial samples of cheek skin of children were sequenced by 16S rRNA V1-V2 region. Four skin isolated bacterial fermentation supernatants were tested for effects on S. aureus growth, membrane formation, and induction of cytokine secretion from HaCaT cells. Results: Bacterial diversity decreased significantly in skin with severe AD compared to healthy skin (p < 0.01). Seven phyla had content >1%, 4 of which differed in AD (p < 0.05). 38 genera had content >1%, 15 differed (p < 0.05). Differences in 8 species were observed (p < 0.05). In vitro antibacterial and cellular experiments showed that S. aureus growth, biofilm formation, and induction of interleukin (IL)-1α and IL-6 secretion from HaCaT cells were significantly inhibited by Klebsiella oxytoca, Kocuria rhizophila, and Staphylococcus epidermidis culture supernatants (p < 0.05). Conclusion: Skin microbiome changes in children varied with age and with AD. There were complex interactions between skin isolated bacteria and S. aureus which could inhibit S. aureus growth and biofilm formation in vitro, suggesting that these microorganisms could be used in AD treatment.