460nm可见光杀灭浮游状态和生物膜内大肠埃希菌的实验研究

Experimental study on inhibition of planktonic and biofilm Escherichia coli by 460 nm visible light

目的探讨460 nm可见光(蓝光)对浮游状态和生物膜内大肠埃希菌的作用。方法自烧伤病房采集大肠埃希菌标本,经细菌鉴定仪鉴定;分别采用不同能量的460 nm可见光照射浮游状态大肠埃希菌,分别采用平板划线法、活/死菌染色法评价460 nm可见光的杀菌效果。制作大肠埃希菌生物膜模型,FM 1-43及结晶紫鉴定后给予240 J/cm2和360 J/cm2的460 nm可见光照射,活/死菌染色激光共聚焦显微镜观察生物膜内细菌的存活情况。以未经照射处理的标本作为对照。结果大肠埃希菌标本经60 J/cm2及以上剂量的460 nm可见光照射后,与对照组比较,平板划线后的菌落数明显减少,并呈剂量效应关系;240 J/cm2和360 J/cm2的460 nm可见光照射后,生物膜内各层细菌的死亡率均显著高于对照组。结论 460 nm可见光具有高效杀灭浮游状态和生物膜内大肠埃希菌的作用。

Objective To investigate the effects of 460 nm visible light （blue light） on planktonic and biofilm Escherichia coli （E. coli）. Methods E. coli samples were isolated from wards of the Department of Burn and identified by the microbial identification system. The planktonic E. coli were irradiated by 460 nm visible light of different energy and the anti-bacteria effects of 460 nm visible light were evaluated by the colony counting and LIVE/DEAD staining. The E. coli biofilm model was built and irradiated by 460nm visible light of 240 J/cm2 and 360 J/cm2 after being identified by FM 1-43 and crystal violet staining. The survival of E. coli in the biofilm was observed by the LIVE/DEAD staining and laser confocal microscope and compared to samples without being irradiated by the light. Results Compared to the control group, the number of colonies of E. coli samples decreased significantly after being irradiated by 460 nm visible light of 60 J/cm2 and above and showed dose effect relation. The death rate of E. coli in the biofilm was significantly higher than that of E. coli of the control group after being irradiated by 460 nm visible fight of 240 J/cm2 and 360 J/cm2. Conclusion Visible fight of 460 nm can effectively inhibit planktonic and biofilm E. coli.