Staphylococcus aureus is a major foodborne pathogen that leads to various diseases due to its biofilm and virulence factors. This study aimed to investigate the inhibitory effect of 2R,3R-dihydromyricetin (DMY), a natural flavonoid compound, on the biofilm formation and virulence of S. aureus, and to explore the mode of action using transcriptomic and proteomic analyses. Microscopic observation revealed that DMY could remarkably inhibit the biofilm formation by S. aureus, leading to a collapse on the biofilm architecture and a decrease in viability of biofilm cell. Moreover, the hemolytic activity of S. aureus was reduced to 32.7% after treatment with subinhibitory concentration of DMY (p < 0.01). Bioinformation analysis based on RNA-sequencing and proteomic profiling revealed that DMY induced 262 differentially expressed genes and 669 differentially expressed proteins (p < 0.05). Many downregulated genes and proteins related to surface proteins were involved in biofilm formation, including clumping factor A (ClfA), iron-regulated surface determinants (IsdA, IsdB, and IsdC), fibrinogen-binding proteins (FnbA, FnbB), and serine protease. Meanwhile, DMY regulated a wide range of genes and proteins enriched in bacterial pathogenesis, cell envelope, amino acid metabolism, purine and pyrimidine metabolism, and pyruvate metabolism. These findings suggest that DMY targets S. aureus through multifarious mechanisms, and especially prompt that interference of surface proteins in cell envelope would lead to attenuation of biofilm and virulence.

中文翻译：

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2R,3R-二氢杨梅素对金黄色葡萄球菌的抗菌机制：基于转录组学和蛋白质组学分析破译对生物膜和毒力的抑制作用。

金黄色葡萄球菌是一种主要的食源性病原体，由于其生物膜和毒力因子而导致各种疾病。本研究旨在研究天然类黄酮化合物 2R,3R-二氢杨梅素 (DMY) 对金黄色葡萄球菌生物膜形成和毒力的抑制作用，并使用转录组学和蛋白质组学分析探索作用模式。显微镜观察表明，DMY 可显着抑制金黄色葡萄球菌形成生物膜，导致生物膜结构崩溃，生物膜细胞活力降低。此外，在用亚抑制浓度的 DMY 处理后，金黄色葡萄球菌的溶血活性降低至 32.7% (p < 0.01)。基于 RNA 测序和蛋白质组学分析的生物信息分析表明，DMY 诱导了 262 个差异表达基因和 669 个差异表达蛋白 (p < 0.05)。许多与表面蛋白相关的下调基因和蛋白质参与生物膜形成，包括凝集因子 A (ClfA)、铁调节表面决定簇（IsdA、IsdB 和 IsdC）、纤维蛋白原结合蛋白（FnbA、FnbB）和丝氨酸蛋白酶. 同时，DMY 调节广泛的基因和蛋白质，这些基因和蛋白质富含细菌发病机制、细胞包膜、氨基酸代谢、嘌呤和嘧啶代谢以及丙酮酸代谢。这些发现表明 DMY 通过多种机制靶向金黄色葡萄球菌，尤其提示细胞包膜中表面蛋白的干扰会导致生物膜和毒力的减弱。