Wang Yucheng, Harrington Olivia D, Wang Ying, Murray Clinton K, Hamblin Michael R, Dai Tianhong
Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School; Department of Medical Oncology, Beijing Institute of Translational Medicine, Chinese Academy of Sciences; Cancer Center, Aviation General Hospital, Beijing.
Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School.
J Vis Exp. 2017 Apr 28(122):54997. doi: 10.3791/54997.
Burn infections continue to be an important cause of morbidity and mortality. The increasing emergence of multidrug-resistant (MDR) bacteria has led to the frequent failure of traditional antibiotic treatments. Alternative therapeutics are urgently needed to tackle MDR bacteria. An innovative non-antibiotic approach, antimicrobial blue light (aBL), has shown promising effectiveness against MDR infections. The mechanism of action of aBL is not yet well understood. It is commonly hypothesized that naturally occurring endogenous photosensitizing chromophores in bacteria (e.g., iron-free porphyrins, flavins, etc.) are excited by aBL, which in turn produces cytotoxic reactive oxygen species (ROS) through a photochemical process. Unlike another light-based antimicrobial approach, antimicrobial photodynamic therapy (aPDT), aBL therapy does not require the involvement of an exogenous photosensitizer. All it needs to take effect is the irradiation of blue light; therefore, it is simple and inexpensive. The aBL receptors are the endogenous cellular photosensitizers in bacteria, rather than the DNA. Thus, aBL is believed to be much less genotoxic to host cells than ultraviolet-C (UVC) irradiation, which directly causes DNA damage in host cells. In this paper, we present a protocol to assess the effectiveness of aBL therapy for MDR Acinetobacter baumannii infections in a mouse model of burn injury. By using an engineered bioluminescent strain, we were able to noninvasively monitor the extent of infection in real time in living animals. This technique is also an effective tool for monitoring the spatial distribution of infections in animals.
烧伤感染仍然是发病和死亡的重要原因。多重耐药（MDR）细菌的不断出现导致传统抗生素治疗频繁失败。迫切需要替代疗法来应对多重耐药细菌。一种创新的非抗生素方法——抗菌蓝光（aBL），已显示出对多重耐药感染有良好的疗效。aBL的作用机制尚未完全明确。通常推测，细菌中天然存在的内源性光敏发色团（如无铁卟啉、黄素等）被aBL激发，进而通过光化学过程产生细胞毒性活性氧（ROS）。与另一种基于光的抗菌方法——抗菌光动力疗法（aPDT）不同，aBL疗法不需要外源性光敏剂的参与。其发挥作用所需要的只是蓝光照射；因此，它简单且成本低廉。aBL的受体是细菌内源性细胞光敏剂，而非DNA。因此，人们认为aBL对宿主细胞的遗传毒性比紫外线-C（UVC）照射小得多，UVC照射会直接导致宿主细胞DNA损伤。在本文中，我们提出了一种方案，用于评估aBL疗法在烧伤小鼠模型中对多重耐药鲍曼不动杆菌感染的疗效。通过使用一种工程化的生物发光菌株，我们能够在活体动物中实时无创监测感染程度。这项技术也是监测动物体内感染空间分布的有效工具。
