Blue light for drug resistant skin and soft tissue infections

描述（由申请人提供）：皮肤和软组织感染（SSTI）是临床实践中遇到的最常见问题之一，每年在美国影响数百万人。这些感染的范围可能从简单的浅表SSTI到危及生命的复杂的深部SSTI。SSTI的治疗因多重耐药病原菌的出现而变得非常复杂。因此，迫切需要开发新的治疗方法。本提案的目的是研究非抗生素方法，抗菌蓝光疗法，对多重耐药SSTI的效用。具体而言，我们建议： 目的1：证明抗微生物蓝光疗法对浅表或深部SSTI的疗效， 感染革兰氏阳性耐甲氧西林金黄色葡萄球菌（MRSA）或革兰氏阴性多重耐药铜绿假单胞菌的啮齿动物。我们将使用小鼠浅表性脓疱和大鼠深部切口手术部位感染分别作为浅表和深部SSTI的代表性模型。将对免疫活性和免疫功能低下的小鼠/大鼠进行检测。将使用3x 105和3x 107菌落形成单位/啮齿动物的细菌接种物分别代表低和高接种物引起的感染。我们将使用活体生物发光成像技术，以定量和非侵入性监测在真实的时间在活的动物感染的程度。分别在细菌接种后30 min、24 h和48 h启动蓝光（405-415 nm波长）。蓝光疗法的疗效将与临床使用的抗生素治疗SSTI进行比较。 目的2：确定抗菌蓝光治疗SSTI的潜在副作用。我们将首先在体外比较病原菌和宿主细胞对蓝光灭活的敏感性。我们还将确定致病菌是否可以对蓝光灭活产生抗性。该实验将通过在体外进行细菌亚致死蓝光灭活的重复循环，然后进行细菌再生长来实施。最后，我们将通过体外和体内照射宿主细胞后的碱性彗星试验来研究蓝光是否对宿主细胞具有遗传毒性。这些具体目标的成功完成将为评估SSTI的抗菌蓝光疗法的疗效（目标1）以及潜在副作用（目标2）提供所需的基础，并将有助于建立以下方案： 这种预防/治疗选择的使用。鉴于目前对多重耐药SSTI的管理存在重大缺陷，这种使用蓝光的新技术具有巨大的潜力。

DESCRIPTION (provided by applicant): Skin and soft tissue infections (SSTI) are one of the most common problems encountered in clinical practice and affect millions of individuals annually in the United States. These infections may range from uncomplicated superficial SSTI to life-threatening complicated deep SSTI. Treatment of SSTI has been significantly complicated by the increasing emergence of multidrug-resistant pathogenic bacteria. As a result, there is a pressing need for the development of new therapeutic approaches. The objective of this proposal is to investigate the utility of a non-antibiotic approach, antimicrobial blue light theray, for multidrug-resistant SSTI. Specifically, we propose to: Aim 1: Demonstrate the efficacy of antimicrobial blue light therapy for superficial or deep SSTI in rodents infected with Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) or Gram-negative multidrug-resistant Pseudomonas aeruginosa. We will use superficial impetigo in mice and deep incisional surgical site infections in rats as the representative models of superficial and deep SSTI, respectively. Both immunocompetent and immunocompromised mice/rats will be tested. Bacterial inocula of 3x105 and 3x107 colony-forming units/rodent will be used to represent the infections caused by a low and a high inoculum, respectively. We will use the in vivo bioluminescence imaging technique to quantitatively and noninvasively monitor in real time the extent of infections in living animals. Blue light (405-415 nm wavelength) will be initiated at 30 min, 24 h, and 48 h after bacterial inoculation, respectively. The efficacy found with blue light therapy will be compared with that of clinically used antibiotics for SSTI. Aim 2: Determine the potential side effects of antimicrobial blue light therapy for SSTI. We will first compare the susceptibilities to blue light inactivation in vitro between pathogenic bacteria and host cells. We will also determine whether the pathogenic bacteria can develop resistance to blue light inactivation. The experiment will be implemented by carrying out repeated cycles of sub-lethal blue light inactivation of bacteria in vitro followed by bacterial regrowth. Finally, wewill investigate whether blue light is genotoxic to host cells by using the alkaline comet assay after irradiation of host cells in vitro and in vivo. Successful completion of these specific aims will provide the foundation required to assess the efficacy (Aim 1) as well as the potential side effects (Aim 2) of antimicrobial blue light therapy for SSTI, and will help establish protocols for the use of this prophylaxis/therapeutic option. Given the significant drawbacks in current management of multidrug-resistant SSTI, this new technology using blue light exhibits great potential.