Atopic dermatitis (AD) is commonly associated with colonization by Staphylococcus aureus in the affected skin. To understand the role of S. aureus in the development of AD, we performed whole-genome sequencing of S. aureus strains isolated from the cheek skin of 268 Japanese infants 1 and 6 months after birth. About 45% of infants were colonized with S. aureus at 1 month regardless of AD outcome. In contrast, skin colonization by S. aureus at 6 months of age increased the risk of developing AD. Acquisition of dysfunctional mutations in the S. aureus Agr quorum-sensing (QS) system was primarily observed in strains from 6-month-old infants who did not develop AD. Expression of a functional Agr system in S. aureus was required for epidermal colonization and the induction of AD-like inflammation in mice. Thus, retention of functional S. aureus agr virulence during infancy is associated with pathogen skin colonization and the development of AD.

特应性皮炎（AD）通常与金黄色葡萄球菌在受影响的皮肤中定植有关。为了了解金黄色葡萄球菌在AD发生中的作用，我们对从268例日本婴儿出生后1个月和6个月的脸颊皮肤分离的金黄色葡萄球菌进行了全基因组测序。不论AD结果如何，约45％的婴儿在1个月时都被金黄色葡萄球菌定植。相比之下，金黄色葡萄球菌在6个月大时皮肤定植会增加发生AD的风险。金黄色葡萄球菌功能异常突变的获得主要在来自未患AD的6个月大婴儿的菌株中观察到Agr群体感应（QS）系统。金黄色葡萄球菌中功能性Agr系统的表达是表皮定植和诱导小鼠AD样炎症所必需的。因此，婴儿期功能性金黄色葡萄球菌agr毒力的保留与病原体皮肤定植和AD的发展有关。