Blue light for drug resistant skin and soft tissue infections

描述(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的问题之一，每年在美国影响数百万人。这些感染的范围从简单的浅表SSTI到危及生命的复杂的深部SSTI。由于多重耐药病原菌的出现，SSTI的治疗已经变得非常复杂。因此，迫切需要开发新的治疗方法。这项建议的目的是研究一种非抗生素方法，即抗菌蓝光疗法，用于治疗多药耐药的SSTI。具体来说，我们建议： 目的1：验证抗菌蓝光疗法治疗浅表性或深部系统性红斑狼疮的疗效。 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。我们将以小鼠浅表脓疱病和大鼠深部切口感染分别作为浅部和深部SSTI的代表性模型。免疫活性和免疫功能低下的小鼠/大鼠都将接受测试。菌落形成单位数为3×105和3×107的细菌接种量分别代表低接种量和高接种量引起的感染。我们将使用体内生物发光成像技术来定量和非侵入性地实时监测活体动物的感染程度。接种细菌后30分钟、24小时、48小时分别发出蓝光(波长405~415 nm)。蓝光疗法的疗效将与临床上使用的抗生素治疗SSTI的疗效进行比较。 目的2：确定抗菌蓝光疗法治疗系统性红斑狼疮的潜在副作用。我们将首先比较病原菌和宿主细胞在体外对蓝光灭活的敏感性。我们还将确定病原菌是否能对蓝光灭活产生抵抗力。这项实验将通过在体外进行亚致命蓝光灭活细菌的重复循环来实施，然后细菌重新生长。最后，我们将利用体外和体内照射宿主细胞后的碱性彗星实验来研究蓝光是否对宿主细胞产生遗传毒性。这些具体目标的成功完成将为评估抗菌蓝光疗法治疗SSTI的疗效(目标1)和潜在副作用(目标2)提供所需的基础，并将有助于制定 这一预防/治疗方案的使用。考虑到目前耐多药SSTI管理中的重大缺陷，这项利用蓝光的新技术显示出巨大的潜力。

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.