College of Veterinary Medicine, Sichuan Agriculture University, Huimin Lu 211, Wenjiang, Chengdu, China.
World J Microbiol Biotechnol. 2018 Apr 18;34(5):64. doi: 10.1007/s11274-018-2446-3.
Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that causes various diseases in both humans and animals. With the increased prevalence of methicillin-resistant S. aureus, the therapeutic effects of commonly used antibiotics are limited against S. aureus infection. Novel treatment strategies and new antibiotics are needed urgently to address this concern. Many studies have shown that virulence factors secreted from S. aureus play vital roles in their pathogenic processes. Alpha-hemolysin (Hla), an important exotoxin in S. aureus, is one such virulence factor that increases sensitivity of multiple host cells to S. aureus resulting in various diseases. Eriodictyol is a flavonoid compound that exists in many fruits and vegetables. In this study, eriodictyol was demonstrated to inhibit the expression of Hla by hemolysis assays, western blotting, and RT-qPCR at the sub-minimal inhibitory concentration. In live/dead and cytotoxicity assays, the results showed that eriodictyol protected A549 cells against Hla-induced injury in a dose-dependent manner. The minimal inhibitory concentration of eriodictyol against S. aureus was 512 µg/mL. Eriodictyol can downregulate S. aureus Hla at both the expressional and transcriptional levels without affecting S. aureus growth. In addition, cell assays had proved that eriodictyol could protect A549 cells against Hla damage. Eriodictyol could therefore have the potential to treat S. aureus infection targeting Hla.
金黄色葡萄球菌（S. aureus）是一种常见的致病菌，可引起人类和动物的各种疾病。随着耐甲氧西林金黄色葡萄球菌（MRSA）的患病率增加，常用抗生素对金黄色葡萄球菌感染的治疗效果有限。急需新的治疗策略和新型抗生素来解决这一问题。许多研究表明，金黄色葡萄球菌分泌的毒力因子在其致病过程中起着至关重要的作用。α-溶血素（Hla）是金黄色葡萄球菌中的一种重要外毒素，是增加多种宿主细胞对金黄色葡萄球菌敏感性从而导致各种疾病的一种毒力因子。圣草次苷是一种存在于许多水果和蔬菜中的类黄酮化合物。在这项研究中，溶血试验、Western blot 和 RT-qPCR 结果表明，圣草次苷在亚最小抑制浓度下可抑制 Hla 的表达。在死活和细胞毒性试验中，结果表明圣草次苷以剂量依赖性方式保护 A549 细胞免受 Hla 诱导的损伤。圣草次苷对金黄色葡萄球菌的最小抑制浓度为 512 µg/mL。圣草次苷可以在表达和转录水平下调金黄色葡萄球菌 Hla，而不影响金黄色葡萄球菌的生长。此外，细胞试验已经证明圣草次苷可以保护 A549 细胞免受 Hla 损伤。因此，圣草次苷有可能通过靶向 Hla 来治疗金黄色葡萄球菌感染。
