Department of Clinical Research, University of Bern, Bern, Switzerland.
Appl Environ Microbiol. 2013 Apr;79(8):2605-11. doi: 10.1128/AEM.03608-12. Epub 2013 Feb 8.
Bacteria are rapidly killed on copper surfaces, and copper ions released from the surface have been proposed to play a major role in the killing process. However, it has remained unclear whether contact of the bacteria with the copper surface is also an important factor. Using laser interference lithography, we engineered copper surfaces which were covered with a grid of an inert polymer which prevented contact of the bacteria with the surface. Using Enterococcus hirae as a model organism, we showed that the release of ionic copper from these modified surfaces was not significantly reduced. In contrast, killing of bacteria was strongly attenuated. When E. hirae cells were exposed to a solid iron surface, the loss of cell viability was the same as on glass. However, exposing cells to iron in the presence of 4 mM CuSO4 led to complete killing in 100 min. These experiments suggest that contact killing proceeds by a mechanism whereby the metal-bacterial contact damages the cell envelope, which, in turn, makes the cells susceptible to further damage by copper ions.
细菌在铜表面迅速被杀灭，而从表面释放出的铜离子被认为在杀菌过程中起主要作用。然而，接触铜表面是否也是一个重要因素仍不清楚。我们使用激光干涉光刻技术，在铜表面制造了一种惰性聚合物网格，以防止细菌与表面接触。我们使用肠球菌作为模型生物，结果表明，从这些改性表面释放的离子铜并没有明显减少。相比之下，细菌的杀灭作用大大减弱。当肠球菌细胞暴露于固体铁表面时，细胞活力的丧失与玻璃相同。然而，当细胞在 4mM CuSO4 的存在下暴露于铁时，在 100 分钟内完全杀死了细胞。这些实验表明，接触式杀菌是通过一种机制进行的，其中金属与细菌的接触会破坏细胞包膜，进而使细胞容易受到铜离子的进一步损伤。
