van der Borden Arnout J, van der Werf Hester, van der Mei Henny C, Busscher Henk J
Department of Biomedical Engineering, University of Groningen, Groningen, The Netherlands.
Appl Environ Microbiol. 2004 Nov;70(11):6871-4. doi: 10.1128/AEM.70.11.6871-6874.2004.
Biomaterial-centered infections of orthopedic percutaneous implants are serious complications which can ultimately lead to osteomyelitis, with devastating effects on bone and surrounding tissues, especially since the biofilm mode of growth offers protection against antibiotics and since removal frequently is the only ultimate solution. Recently, it was demonstrated that as a possible pathway to prevent infections of percutaneous stainless steel implants, electric currents of 60 to 100 microA were effective at stimulating the detachment of initially adhering staphylococci from surgical stainless steel. However, initially adhering bacteria are known to adhere more reversibly than bacteria growing in the later stages of biofilm formation. Hence, the aim of this study was to examine whether a growing Staphylococcus epidermidis biofilm can be stimulated to detach from surgical stainless steel by the use of electric currents. In separate experiments, four currents, i.e., 60 and 100 microA of direct current (DC) and 60 and 100 microA of block current (50% duty cycle, 1 Hz), were applied for 360 min to stimulate the detachment of an S. epidermidis biofilm that had grown for 200 min. A 100-microA DC yielded 78% detachment, whereas a 100-microA block current under the same experimental conditions yielded only 31% detachment. The same trend was found for 60 microA, with 37% detachment for a DC and 24% for a block current. Bacteria remaining on the surface after the current application were less viable than they were prior to the current application, as demonstrated by confocal laser scanning microscopy. In conclusion, these results suggest that DCs are preferred for curing infections.
骨科经皮植入物以生物材料为中心的感染是严重的并发症，最终可导致骨髓炎，对骨骼和周围组织造成毁灭性影响，特别是因为生物膜生长模式提供了对抗生素的保护作用，而且通常移除植入物是唯一的最终解决办法。最近有研究表明，作为预防经皮不锈钢植入物感染的一种可能途径，60至100微安的电流可有效刺激初始附着的葡萄球菌从手术不锈钢上脱离。然而，已知初始附着的细菌比生物膜形成后期生长的细菌附着得更可逆。因此，本研究的目的是检验是否可以通过使用电流刺激表皮葡萄球菌生物膜从手术不锈钢上脱离。在单独的实验中，分别施加四种电流，即60和100微安的直流电（DC）以及60和100微安的方波电流（占空比50%，1赫兹），持续360分钟，以刺激已经生长200分钟的表皮葡萄球菌生物膜脱离。100微安的直流电可使78%的细菌脱离，而在相同实验条件下，100微安的方波电流仅使31%的细菌脱离。60微安时也发现了相同的趋势，直流电使37%的细菌脱离，方波电流使24%的细菌脱离。共聚焦激光扫描显微镜显示，施加电流后留在表面的细菌比施加电流前的活力更低。总之，这些结果表明直流电更适合用于治疗感染。
