Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea.
Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, Republic of Korea.
Appl Environ Microbiol. 2018 Dec 13;85(1). doi: 10.1128/AEM.01952-18. Print 2019 Jan 1.
The purpose of this study was to investigate the synergistic bactericidal effect of 222-nm KrCl excilamp and 254-nm low-pressure (LP) Hg lamp simultaneous treatment against O157:H7, subsp. serovar Typhimurium, and in tap water and to identify the synergistic bactericidal mechanism. Sterilized tap water inoculated with pathogens was treated individually or simultaneously with a 254-nm LP Hg lamp or 222-nm KrCl excilamp. Overall, for all pathogens, an additional reduction was found compared to the sum of the log unit reductions of the individual treatments resulting from synergy in the simultaneous treatment with both kinds of lamps. In order to identify the mechanism of this synergistic bactericidal action, the form and cause of membrane damage were analyzed. Total reactive oxygen species (ROS) and superoxide generation as well as the activity of ROS defense enzymes then were measured, and the overall mechanism was described as follows. When the 222-nm KrCl excilamp and the 254-nm LP Hg lamp were treated simultaneously, inactivation of ROS defense enzymes by the 222-nm KrCl excilamp induced additional ROS generation following exposure to 254-nm LP Hg lamp (synergistic) generation, resulting in synergistic lipid peroxidation in the cell membrane. As a result, there was a synergistic increase in cell membrane permeability leading to a synergistic bactericidal effect. This identification of the fundamental mechanism of the combined disinfection system of the 222-nm KrCl excilamp and 254-nm LP Hg lamp, which exhibited a synergistic bactericidal effect, can provide important baseline data for further related studies or industrial applications in the future. Contamination of pathogenic microorganisms in water plays an important role in inducing outbreaks of food-borne illness by causing cross-contamination in foods. Thus, proper disinfection of water before use in food production is essential to prevent outbreaks of food-borne illness. As technologies capable of selecting UV radiation wavelengths (such as UV-LEDs and excilamps) have been developed, wavelength combination treatment with UV radiation, which is widely used in water disinfection systems, is actively being studied. In this regard, we have confirmed synergistic bactericidal effects in combination with 222-nm and 254-nm wavelengths and have identified mechanisms for this. This study clearly analyzed the mechanism of synergistic bactericidal effect by wavelength combination treatment, which has not been attempted in other studies. Therefore, it is also expected that these results will play an important role as baseline data for future research on, as well as industrial applications for, the disinfection strategy of effective wavelength combinations.
本研究旨在探讨 222nmKrCl 准分子灯和 254nm 低压（LP）汞灯联合处理对 O157:H7、鼠伤寒沙门氏菌 subsp. 和 的协同杀菌效果，并确定协同杀菌机制。将病原体消毒的自来水单独或同时用 254nmLP 汞灯或 222nmKrCl 准分子灯处理。总的来说，与单独处理相比，所有病原体在同时使用两种灯的协同处理中都发现了额外的对数单位减少，从而表现出协同作用。为了确定这种协同杀菌作用的机制，分析了膜损伤的形式和原因。然后测量了总活性氧（ROS）和超氧化物的产生以及 ROS 防御酶的活性，并描述了总体机制如下。当 222nmKrCl 准分子灯和 254nmLP 汞灯同时处理时，222nmKrCl 准分子灯对 ROS 防御酶的失活诱导了暴露于 254nmLP 汞灯后 ROS 的额外生成（协同作用），导致细胞膜中协同脂质过氧化作用。结果，细胞膜通透性协同增加，导致协同杀菌作用。这种鉴定 222nmKrCl 准分子灯和 254nmLP 汞灯联合消毒系统协同杀菌作用的基本机制，可以为未来进一步的相关研究或工业应用提供重要的基础数据。水中致病性微生物的污染通过在食品中造成交叉污染而在引起食源性疾病爆发中起着重要作用。因此，在食品生产中使用前对水进行适当消毒对于防止食源性疾病爆发至关重要。随着能够选择紫外线辐射波长的技术（如 UV-LED 和准分子灯）的发展，紫外线辐射的波长组合处理已在广泛用于水消毒系统的领域中得到积极研究。在这方面，我们已经证实了与 222nm 和 254nm 波长的组合的协同杀菌效果，并确定了这种效果的机制。本研究通过波长组合处理明确分析了协同杀菌作用的机制，这在其他研究中尚未尝试过。因此，预计这些结果将作为未来有效波长组合消毒策略的研究和工业应用的基础数据发挥重要作用。
