The skin microbiota has been recognized to play an integral role in the physiology and pathology of the skin. The crosstalk between skin and the resident microbes has been extensively investigated using two-dimensional (2D) and three-dimensional (3D) cell cultures in vitro; however, skin colonization by multiple species and the effects of interspecific interactions on the structure and function of skin remains to be elucidated. This study reports the establishment of a mixed infection model, incorporating both commensal (Staphylococcus epidermidis) and pathogenic (Staphylococcus aureus) bacteria, based on a 3D human epidermal model. We observed that co-infecting the 3D epidermal model with S. aureus and S. epidermidis restricted the growth of S. aureus. In addition, S. aureus induced epidermal cytotoxicity, and the release of proinflammatory cytokines was attenuated by the S. aureus-S. epidermidis mixed infection model. S. epidermidis also inhibited the invasion of the deeper epidermis by S. aureus, eliciting protective effects on the integrity of the epidermal barrier. This 3D culture-based mixed infection model would be an effective replacement for existing animal models and 2D cell culture approaches for the evaluation of diverse biotic and abiotic factors involved in maintaining skin health.

皮肤微生物群已被公认为在皮肤的生理学和病理学中起着不可或缺的作用。已使用二维 (2D) 和三维 (3D) 细胞培养广泛研究了皮肤与常驻微生物之间的串扰体外; 然而，多个物种的皮肤定植以及种间相互作用对皮肤结构和功能的影响仍有待阐明。该研究报告了混合感染模型的建立，包括两种共生（表皮葡萄球菌) 和致病性 (金黄色葡萄球菌) 细菌，基于 3D 人类表皮模型。我们观察到，将 3D 表皮模型与金黄色葡萄球菌 和 表皮葡萄球菌 限制了生长 金黄色葡萄球菌. 此外，金黄色葡萄球菌 诱导表皮细胞毒性，促炎细胞因子的释放被减弱 金黄色葡萄球菌——表皮葡萄球菌 混合感染模型。 表皮葡萄球菌 还通过以下方式抑制了深层表皮的侵袭 金黄色葡萄球菌，引发对表皮屏障完整性的保护作用。这种基于 3D 培养的混合感染模型将有效替代现有的动物模型和 2D 细胞培养方法，用于评估参与维持皮肤健康的各种生物和非生物因素。