Abstract: 【Abstract】 Objective To investigate changes in skin microecological structures and functions between acute and remission phases in adult patients with severe atopic dermatitis （AD）. Methods From October 2019 to November 2020, skin scale specimens were collected from 5 body sites （cheeks, cubital fossa, back of the hand, abdomen, lower limbs） of 4 adult patients with severe AD in the acute and remission phases, who visited the outpatient clinic of Guangzhou Institute of Dermatology. The next-generation high-throughput sequencing was performed for metagenomic sequencing to construct the microbial gene catalogue of these specimens, followed by gene annotation and bioinformatics analysis for each sample. Results A total of 18 phyla, 37 classes, 73 orders, 142 families, 237 genera, and 331 species were identified in the skin specimens from the 4 patients with severe AD. The patients with AD in the remission phase showed significantly increased diversity of skin microbiota and markedly different relative abundance of skin microorganisms compared with those in the acute phase （both P < 0.05）. At the microbial species level, Staphylococcus aureus showed the highest impact on the acute phase of AD, while Staphylococcus epidermidis, Moraxella osloensis, Francisella sp., Staphylococcus cohnii, Staphylococcus warneri, Malassezia globosa and Malassezia restricta were enriched in the remission phase of AD with the absolute value of the common logarithm of the linear discriminant analysis score > 2 （Kruksal-Wallis test, all P < 0.05）. As KEGG pathway enrichment analysis showed, the differentially abundant genes were annotated into a total of 355 functional pathways, of which 38 pathways were significantly enriched （all P < 0.05）, mainly involving Staphylococcus aureus infection, tryptophan metabolism, histidine metabolism, nitrogen metabolism, metabolism of arginine and proline, biosynthesis and degradation of valine, leucine and isoleucine, fatty acid degradation, peroxisome proliferator-activated receptor signaling pathway, etc. Conclusion The skin microecological structure significantly differed between the acute and remission phases among the patients with severe AD, which may be related to multiple functional pathways, such as Staphylococcus aureus infection, tryptophan metabolism, histidine metabolism and nitrogen metabolism.

Key words: Dermatitis, atopic, Microbial consortia, Skin, Metagenomics, Metabolic networks and pathways