Yang Penggao, Wang Ning, Wang Chuan, Yao Yufeng, Fu Xiujun, Yu Weirong, Cai Raymond, Yao Min
Department of Burns and Plastic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201999, China.
Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
J Photochem Photobiol B. 2017 Jan;166:311-322. doi: 10.1016/j.jphotobiol.2016.12.001. Epub 2016 Dec 18.
A growing number of researches demonstrate that light with a wavelength between 400 and 500nm, namely blue light (BL), has exhibited antibacterial effects on methicillin-resistant Staphylococcus aureus (MRSA) and other microbes. However, there is insufficient evidence to show that BL kills MRSA inside biofilm and the mechanisms underlying the antibacterial effects remain unclear. Here we demonstrate that BL irradiation with 460nm effectively eliminated both planktonic and biofilm MRSA in a dose-dependent manner by utilizing a planktonic MRSA or MRSA biofilm model. Furthermore, using a animal model of skin wound infections with MRSA, we found that 460nm BL showed a therapeutic effect on MRSA infected wounds in mice with significant killing of MRSA, better survival and wound healing. Moreover, RNA sequencing was used to analyze differential gene expressions in MRSA genome after BL irradiation. Our data showed that about one third of up-regulated genes were phage-related. Using phage inhibitor GS-11P, increased prophage activation in MRSA cells induced by BL irradiation was blocked and phage particles were observed. The results indicate that blue visible light irradiation with 460nm is a novel tool for eliminating both planktonic and biofilm MRSA. Prophage activation may be involved in the process. This study may provide a new perspective to understand the antibacterial mechanism by BL.
越来越多的研究表明，波长在400至500纳米之间的光，即蓝光（BL），已对耐甲氧西林金黄色葡萄球菌（MRSA）和其他微生物表现出抗菌作用。然而，尚无足够证据表明蓝光能杀死生物膜内的MRSA，其抗菌作用的潜在机制仍不清楚。在此，我们通过使用浮游MRSA或MRSA生物膜模型证明，460纳米的蓝光照射以剂量依赖的方式有效消除了浮游和生物膜状态的MRSA。此外，利用MRSA皮肤伤口感染的动物模型，我们发现460纳米蓝光对感染MRSA的小鼠伤口具有治疗作用，能显著杀灭MRSA，提高生存率并促进伤口愈合。此外，采用RNA测序分析蓝光照射后MRSA基因组中的差异基因表达。我们的数据显示，约三分之一上调的基因与噬菌体相关。使用噬菌体抑制剂GS-11P，可阻断蓝光照射诱导的MRSA细胞中前噬菌体激活增加，并观察到噬菌体颗粒。结果表明，460纳米的蓝光照射是消除浮游和生物膜状态MRSA的一种新工具。前噬菌体激活可能参与了这一过程。本研究可能为理解蓝光的抗菌机制提供一个新的视角。
