ULTRASONIC ENHANCEMENT OF ANTIBIOTIC ACTION ON BIOFILMS

植入的医疗设备有时会被感染，导致患者死亡 痛苦和额外的手术切除或更换 设备。植入物相关的感染通常可以通过以下方法控制 抗生素治疗，但感染很少能完全治愈 被淘汰。一旦停止抗生素治疗，感染就会 返回。传染性生物通常会分泌多糖粘液 似乎可以保护细菌免受抗生素治疗和细菌侵害 身体的防御机制。关于该问题有多种假设 感染对抗生素治疗的顽抗，其中大多数 表明胞外多糖减少抗生素的转运 或者给细菌提供营养。 拟议的研究重点是消除细菌感染 使用高频压力波（超声波）工作的植入装置 与抗生素协同杀死植入物上的细菌生物膜 设备。我们的初步结果表明超声波可以增强 将抗生素转运至生物膜内的细胞，并可以增强 抗生素对固着细菌和浮游细菌的作用。对于 例如，初步结果显示同时应用庆大霉素 2.25 MHz 超声波对铜绿假单胞菌生物膜的作用可减少铜绿假单胞菌生物膜的数量 生物膜中的活细胞增加了 3 个数量级，并且 67 kHz 超声波通过以下方式降低无柄和浮游铜绿假单胞菌的活力 近3个数量级。同样水平的超声波刺激 当不存在抗生素时，对活力没有影响。效果是 还观察到大肠杆菌和粪链球菌，本研究的具体目标 提案旨在扩大超声波和 抗生素以增加对固体表面生物膜的杀伤力，以及 研究潜在的物理和化学机制。 1.1 该项目将使细菌生物膜暴露于抗生素和 超声波以确定细菌是否被杀死超过完成的范围 仅靠抗生素。铜绿假单胞菌、粪链球菌和大肠杆菌的生物膜 线圈将在聚乙烯、聚氨酯、硅橡胶和 玻璃表面。 1.2 我们已经证明了杀死 P. 的协同效应。 铜绿假单胞菌和大肠杆菌与庆大霉素结合 2.25 MHz 和 67 kHz 超声波。我们将尝试通过探索其他方式来优化杀戮 高达 10 MHz 的频率、各种波形、功率密度和用途 另一种抗生素。 1.3 我们将确定超声波增强运输的程度 通过使用 ESR 自旋标记抗生素将抗生素导入细菌 使用和不使用超声波测量细菌的吸收动力学 刺激。这将证明膜运输是否 受超声波干扰。 1.4 我们将确定超声波增强运输的程度 通过测量运输时的超声波效应在细菌生物膜内 抗生素、氧气和其他分子通过生物膜。

Implanted medical devices sometimes become infected, resulting in patient suffering and additional surgery for removal or replacement of the device. Implant related infections can usually be controlled with antibiotic therapy, but the infection can rarely be completely eliminated. Once the antibiotic therapy is stopped, the infection returns. The infectious organisms usually exude a polysaccharide slime that appears to protect the bacteria from antibiotic therapy and from the body's defense mechanisms. There are several hypotheses concerning the recalcitrance of the infection toward antibiotic therapy, most of which implicate the exopolysaccharide in reducing the transport of antibiotics or nutrients to the bacteria. The proposed research is centered on eliminating bacterial infections on implant devices using high frequency pressure waves (ultrasound) to work synergistically with antibiotics to kill bacterial biofilms on implant devices. Our preliminary results indicate that ultrasound can enhance transport of antibiotic to cells within the biofilm, and can enhance the action of antibiotics against both sessile and planktonic bacteria. For example, preliminary results show simultaneous application of gentamicin and 2.25 MHz ultrasound to P. aeruginosa biofilms reduces the number of viable cells in the biofilm by 3 orders of magnitude, and that 67 kHz ultrasound reduces viability of sessile and planktonic P. aeruginosa by nearly 3 orders of magnitude. This same level of ultrasonic stimulation has no effect on viability when no antibiotic is present. The effect is also observed with E. coil, and S. fecaelis, The specific aims of this proposal are designed to expand this synergistic effect of ultrasound and antibiotics to increase the killing of biofilms on solid surfaces, and to investigate the underlying physical and chemical mechanisms. 1.1 The project will expose a bacterial biofilm to antibiotics and ultrasound to determine if bacteria are killed beyond that accomplished by the antibiotics alone. Biofilms of P. aeruginosa, S. fecaelis, and E. coil will be tested on polyethylene, polyurethane, silicone rubber, and glass surfaces. 1.2 We have already demonstrated synergistic effects in killing P. aeruginosa and E. coli with gentamicin in combination with 2.25 MHz and 67 kHz ultrasound. We will try to optimize the killing by exploring other frequencies up to 10 MHz, various waveforms, power densities, and the use of another antibiotic. 1.3 We will identify the extent to which ultrasound enhances transport of antibiotic into a bacterium by using ESR spin-labeled antibiotics to measure the kinetics of uptake into bacteria with and without ultrasonic stimulation. This will demonstrate whether the membrane transport is perturbed by ultrasound. 1.4 We will identify the extent to which ultrasound enhances transport within a bacterial biofilm by measuring ultrasonic effects upon transport of antibiotics, oxygen and other molecules through the biofilm.