van der Borden A J, van der Mei H C, Busscher H J
Department of Biomedical Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
J Biomed Mater Res B Appl Biomater. 2004 Feb 15;68(2):160-4. doi: 10.1002/jbm.b.20015.
Infection of percutaneous biomaterials implants, such as fixation frames used for the repair of complicated fractures in orthopedics, is a major complication that almost inevitably leads to replacement of the implant. As antibiotic therapy usually has little impact on biomaterial-associated infections, it is the aim of this article to examine whether implant-associated Staphylococcus epidermidis and Staphylococcus aureus strains could be stimulated to detach from a surgical stainless steel anode during application of an electric current. First, bacteria were allowed to adhere from a flowing suspension of physiological ionic strength in a parallel plate flow chamber to a stainless-steel surface, after which the suspension was replaced by a bacterium-free solution with a specified ionic strength (0.5-150-mM potassium phosphate). DC currents ranging from 15 to 125 microA were applied to induce bacterial detachment. Initial detachment decreased with increasing ionic strength at 100 microA. The percentage detachment achieved by application of an electric current after 2.5 h was highest (95%) in 1-mM potassium phosphate and decreased to 15% when the ionic strength exceeded 40 mM. The electric current did not significantly affect the percentage detachment, but initial detachment rates increased with increasing current from 1000 cm(-2) s(-1) at 15 microA to 7000 cm(-2) s(-1) at 125 microA. Although different isolates of S. epidermidis and S. aureus showed different patterns of current-induced detachment, all strains could be stimulated to detach. The results of this study define ionic-strength conditions and electric currents yielding staphylococcal detachment from surgical stainless steel and therewith point to a pathway for the treatment and prevention of percutaneous metal-implant infection.
经皮生物材料植入物的感染，如骨科用于修复复杂骨折的固定架感染，是一种几乎不可避免地导致植入物更换的主要并发症。由于抗生素治疗通常对生物材料相关感染影响甚微，本文旨在研究在施加电流时，与植入物相关的表皮葡萄球菌和金黄色葡萄球菌菌株是否能被刺激从手术不锈钢阳极上脱离。首先，让细菌在平行板流动腔中从具有生理离子强度的流动悬浮液中附着到不锈钢表面，之后将悬浮液换成具有特定离子强度（0.5 - 150 mM磷酸钾）的无菌溶液。施加15至125微安的直流电流以诱导细菌脱离。在100微安时，初始脱离率随离子强度增加而降低。在2.5小时后施加电流实现的脱离百分比在1 mM磷酸钾中最高（95%），当离子强度超过40 mM时降至15%。电流对脱离百分比没有显著影响，但初始脱离率随着电流从15微安时的1000 cm⁻² s⁻¹增加到125微安时的7000 cm⁻² s⁻¹而增加。尽管不同的表皮葡萄球菌和金黄色葡萄球菌分离株表现出不同的电流诱导脱离模式，但所有菌株都能被刺激脱离。本研究结果确定了能使葡萄球菌从手术不锈钢上脱离的离子强度条件和电流，从而为经皮金属植入物感染的治疗和预防指明了一条途径。
