Park Hee-Jin, Kim Jee Yeon, Kim Jaeeun, Lee Joon-Hee, Hahn Ji-Sook, Gu Man Bock, Yoon Jeyong
School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea.
Water Res. 2009 Mar;43(4):1027-32. doi: 10.1016/j.watres.2008.12.002. Epub 2008 Dec 13.
Silver ions have been widely used as disinfectants that inhibit bacterial growth by inhibiting the essential enzymatic functions of the microorganism via interaction with the thiol-group of l-cysteine. However, silver-ion-mediated perturbation of the bacterial respiratory chain has raised the possibility of reactive oxygen species (ROS) generation. We used bacterial reporter strains specifically responding to superoxide radicals and found that silver-ion-mediated ROS-generation affected bactericidal activity. Almost half the log reduction in Escherichia coli and Staphylococcus aureus populations (model strains for gram negative and positive bacteria, respectively) caused by silver-ion disinfection was attributed to ROS-mediated bactericidal activity. The major form of ROS generated was the superoxide-radical; H(2)O(2) was not induced. Furthermore, silver ions strongly enhanced paraquat-induced oxidative stress, indicating close correlation and synergism between the conventional and ROS-mediated silver toxicity. Our results suggest that further studies in silver-based disinfection systems should consider the oxygen concentration and ROS reaction.
银离子已被广泛用作消毒剂，通过与L-半胱氨酸的巯基相互作用抑制微生物的基本酶功能来抑制细菌生长。然而，银离子介导的细菌呼吸链扰动增加了活性氧（ROS）生成的可能性。我们使用了对超氧自由基有特异性反应的细菌报告菌株，发现银离子介导的ROS生成影响杀菌活性。银离子消毒导致的大肠杆菌和金黄色葡萄球菌群体（分别为革兰氏阴性和阳性细菌的模型菌株）对数减少中，几乎一半归因于ROS介导的杀菌活性。产生的ROS的主要形式是超氧自由基；未诱导产生H(2)O(2)。此外，银离子强烈增强百草枯诱导的氧化应激，表明传统的和ROS介导的银毒性之间密切相关且具有协同作用。我们的结果表明，在基于银的消毒系统中进一步研究应考虑氧气浓度和ROS反应。
