Skin bacterial transplant in atopic dermatitis: Knowns, unknowns and emerging trends

Dysbiosis is a key pathogenic factor in the cycle of skin barrier impairment and inflammation in atopic dermatitis (AD). Skin microbial composition in AD is characterized by increased presence of Staphylococcus aureus (S. aureus) and decrease in microbial diversity and commensal bacterial species. Attenuation of S. aureus-driven inflammation aids in breaking the itch-scratch cycle via modulation of the cutaneous immune response. Skin bacterial transplant (SBT), a form of bacteriotherapy, is an intriguing treatment modality for restoration of a healthy skin microbiome in AD patients. Studies on the effects of topically-applied bacterial products, probiotics and SBT have yielded promising results in animal models and human studies of AD. This review discusses the rationale and evidence for SBT in AD and outlines future investigative directions for the clinical application of microbiome restoration in dermatology. (C) 2019 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.