Dual-Wavelength Blue Light Irradiation for Improved Treatment of Staphylococcus aureus Infections

项目摘要/摘要 金黄色葡萄球菌是全球感染的主要原因。近几十年来，对S. 由于抗生素耐药性的增加，金黄色葡萄球菌感染变得越来越困难， 为开发替代疗法的必要性辩护。抗菌蓝光(ABL；405 nm波长)， 一种创新的非药理学方法，由于其内在的活性而引起越来越多的关注。 对广泛的细菌，无论他们的抗生素耐药性概况。然而，它也一直是 发现金黄色葡萄球菌比大多数其他细菌对405 nm ABL的耐受性要强得多。一个潜在的原因是 金黄色葡萄球菌对ABL的较高耐受性是金黄色葡萄球菌中含有葡萄糖素(STX)。STX充当一个 抗氧化剂，并促进金黄色葡萄球菌对405 nm ABL产生的氧化应激的耐受性。幸运的是， 最近的一项研究发现，STX在460 nm波长的照射下容易发生光漂白。这一发现 由此引出我们的中心假设，即460 nm辐射将增强金黄色葡萄球菌对 405 nm ABL的杀伤作用。为了验证这一假设，我们提出了两个具体目标： 在目标1中，我们将首先研究双波长照射(DWI；460 nm，然后是405 nm)的有效性 NM)体外杀灭金黄色葡萄球菌的策略。一组金黄色葡萄球菌分离株，包括ATCC参考菌株和 最近的临床分离株，将被挑选出来。浮游细菌和生物膜都将被研究。我们还将 评估预先应用460 nm照射对405 nm ABL诱导的反应性产生的影响 金黄色葡萄球菌中的氧气物种。此外，作为安全性研究，我们将评估其细胞毒性和遗传毒性。 通过在治疗性DWI照射下处理人细胞以根除S. 金星。最后，我们将确定DWI是否影响免疫细胞产生ROS的能力。 在目标2中，我们将进行一项临床前研究，以确定DWI治疗皮肤的有效性和安全性。 金黄色葡萄球菌在小鼠体内形成脓肿。我们将使用一种生物发光的耐甲氧西林金黄色葡萄球菌(MRSA) 美国300)来感染老鼠，从而允许实时监测活体动物的感染程度 生物发光成像。DWI将在感染后不同的时间点(30分钟、4小时或48小时)开始。至 为了促进光在生物组织中的穿透，我们将使用一种新型的光学透镜-微针阵列贴片来 通过间质将光线照射到感染部位。DWI的疗效将与DWI进行比较。 四环素是临床治疗皮肤金黄色葡萄球菌感染的经验性抗生素。因为它的安全性 研究中，我们将确定DWI对宿主细胞的活性和DNA损伤、伤口愈合、 以及治疗后组织中的炎症反应。 总体而言，成功完成本申请中概述的具体目标将提供 确定弥散注射治疗局限性金黄色葡萄球菌感染的有效性和安全性所需的基金会； 并将帮助制定使用这一创新战略的协议。

PROJECT SUMMARY/ABSTRACT Staphylococcus aureus is a leading cause of infections worldwide. In recent decades, the treatment of S. aureus infections has become increasingly difficult because of the increasing incidence of antibiotic resistance, justifying the need for developing alternative therapeutics. Antimicrobial blue light (aBL; 405 nm wavelength), an innovative nonpharmacological approach, has attracted increasing attention due to its intrinsic activity against a wide range of bacteria irrespective of their antibiotic resistance profiles. However, it has also been found that S. aureus is much more tolerant of 405 nm aBL than most other bacteria. A potential reason for the higher tolerance of S. aureus to aBL is the presence of staphyloxanthin (STX) in S. aureus. STX acts as an antioxidant and facilitates the tolerance of S. aureus to oxidative stress generated by 405 nm aBL. Fortunately, a recent study discovered that STX is prone to photobleaching by 460 nm wavelength irradiation. This finding leads to our central hypothesis that 460 nm irradiation would potentiate the susceptibility of S. aureus to killing by 405 nm aBL. To test this hypothesis, we propose two Specific Aims: In Aim 1, we will first investigate the efficacy of the dual-wavelength irradiation (DWI; 460 nm followed by 405 nm) strategy for killing S. aureus in vitro. A panel of S. aureus isolates, including ATCC reference strains and recent clinical isolates, will be selected. Both planktonic bacteria and biofilms will be studied. We will also assess the effect of the pre-application of 460 nm irradiation on the 405 nm aBL-induced production of reactive oxygen species in S. aureus. Additionally, as the safety study, we will evaluate the cytotoxicity and genotoxicity of DWI to normal human cells by treating human cells under therapeutic exposures of DWI for eradicating S. aureus. Finally, we will determine whether DWI affects the ROS-producing capability of the immune cells. In Aim 2, we will conduct a preclinical study to determine the efficacy and safety of DWI for treating cutaneous S. aureus abscesses in mice. We will use a bioluminescent strain of methicillin-resistant S. aureus (MRSA USA 300) to infect mice, thus allowing real-time monitoring of the extent of infection in living animals using bioluminescence imaging. DWI will be initiated at varying time points (30 min, 4 h, or 48 h) after infection. To facilitate light penetration in biological tissues, we will use a novel optical lens-microneedle array patch to deliver light interstitially to the infection sites. The efficacy found with DWI will be compared with that of systemic tetracycline, an empirical antibiotic therapy in clinic for cutaneous S. aureus infections. As the safety study, we will determine the effects of DWI on the viability and DNA damage of the host cells, wound healing, and inflammatory response in treated tissues. Collectively, the successful completion of the Specific Aims outlined in this application will provide the foundation required to determine the effectiveness and safety of DWI for treating localized S. aureus infections; and will help establish protocols for the use of this innovative strategy.