Abstract The purpose of this study was to investigate the bactericidal activity of copper (Cu, 10 ppm) and ascorbic acid (AA, 0.3% v/v) mixture against Staphylococcus aureus (S. aureus) ATCC 25923 (methicillin-susceptible) and ATCC 700698 (methicillin-resistant) strains. Approximately 5.5 log10 CFU/ml of each strain was individually inoculated into brain heart infusion (BHI) broth containing Cu, AA, and a Cu-AA mixture, and a time-kill assay was conducted to assess the bactericidal activity. In order to determine the efficacy of Cu-AA mixture as a surface decontaminating solution, the cells were first attached to glass slides (~6.5–7.5 log10 CFU per slide) and treated with a Cu-AA mixture for 1 min. The inner membrane permeability of the S. aureus strains was determined by measuring β-Galactosidase activity. Similarly, changes in the protein profile of treated bacterial cells were analyzed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The time-kill study revealed >3.0 log10 CFU/ml reduction in both strains within 24 h of incubation at 37 °C. Attached cells on glass slides were also reduced by > 3.0 log10 CFU per slide after 1 min of exposure to the Cu-AA mixture. The results indicate that the Cu-AA mixture was bactericidal against S. aureus strains and the damage to the inner cell membrane could be attributed to this effect.

中文翻译：

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铜-抗坏血酸混合物对金黄色葡萄球菌的杀菌活性

摘要 本研究的目的是研究铜 (Cu, 10 ppm) 和抗坏血酸 (AA, 0.3% v/v) 混合物对金黄色葡萄球菌 (S. aureus) ATCC 25923（甲氧西林敏感）和 ATCC 的杀菌活性。 700698（耐甲氧西林）菌株。将大约 5.5 log10 CFU/ml 的每种菌株单独接种到含有 Cu、AA 和 Cu-AA 混合物的脑心浸液 (BHI) 肉汤中，并进行时间杀灭试验以评估杀菌活性。为了确定 Cu-AA 混合物作为表面净化溶液的功效，首先将细胞附着在载玻片上（每个载玻片约 6.5–7.5 log10 CFU）并用 Cu-AA 混合物处理 1 分钟。通过测量β-半乳糖苷酶活性来确定金黄色葡萄球菌菌株的内膜渗透性。相似地，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析处理过的细菌细胞蛋白质谱的变化。时间杀灭研究显示，在 37 °C 下孵育 24 小时内，两种菌株的 log10 CFU/ml 减少 >3.0 在暴露于 Cu-AA 混合物 1 分钟后，载玻片上的附着细胞每张载玻片也减少了 > 3.0 log10 CFU。结果表明，Cu-AA 混合物对金黄色葡萄球菌菌株具有杀菌作用，对细胞内膜的损伤可归因于这种作用。暴露于 Cu-AA 混合物 1 分钟后，每张幻灯片 0 log10 CFU。结果表明，Cu-AA 混合物对金黄色葡萄球菌菌株具有杀菌作用，对细胞内膜的损伤可归因于这种作用。暴露于 Cu-AA 混合物 1 分钟后，每张幻灯片 0 log10 CFU。结果表明，Cu-AA 混合物对金黄色葡萄球菌菌株具有杀菌作用，对细胞内膜的损伤可归因于这种作用。