School of Pharmacy, Queen's University Belfast, Belfast, UK.
School of Pharmacy, Queen's University Belfast, Belfast, UK.
Int J Antimicrob Agents. 2021 Jul;58(1):106360. doi: 10.1016/j.ijantimicag.2021.106360. Epub 2021 May 13.
Bacterial spores are an important consideration in healthcare decontamination, with cross-contamination highlighted as a major route of transmission due to their persistent nature. Their containment is extremely difficult due to the toxicity and cost of first-line sporicides.
Susceptibility of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli to phenothiazinium photosensitizers and cationic surfactants under white- or red-light irradiation was assessed by determination of minimum inhibitory concentrations, minimum bactericidal concentrations and time-kill assays. B. subtilis spore eradication was assessed via time-kill assays, with and without nutrient and non-nutrient germinant supplementation of photosensitizer, surfactant and photosensitizer-surfactant solutions in the presence and absence of light.
Under red-light irradiation, >5-log colony-forming units/mL reduction of vegetative bacteria was achieved within 10 min with toluidine blue O (TBO) and methylene blue (MB). Cationic surfactant addition did not significantly enhance spore eradication by photosensitizers (P>0.05). However, addition of a nutrient germinant mixture to TBO achieved a 6-log reduction after 20 min of irradiation, while providing 1-2 log improvement in spore eradication for MB and pyronin Y.
Light-activated photosensitizer solutions in the presence of surfactants and germination-promoting agents provide a highly effective method to eradicate dormant and vegetative bacteria. These solutions could provide a useful alternative to traditional chemical agents used for high-level decontamination and infection control within health care.
细菌孢子是医疗保健消毒的一个重要考虑因素，由于其持久性，交叉污染被强调为主要的传播途径。由于第一线孢子杀菌剂的毒性和成本，它们的控制极其困难。
通过测定最低抑菌浓度、最低杀菌浓度和时间杀伤试验，评估金黄色葡萄球菌、枯草芽孢杆菌、铜绿假单胞菌和大肠杆菌对吩噻嗪类光增敏剂和阳离子表面活性剂在白光或红光照射下的敏感性。通过时间杀伤试验评估枯草芽孢杆菌孢子的根除情况，并在有光和无光条件下，用和不用光增敏剂、表面活性剂和光增敏剂-表面活性剂溶液的营养和非营养发芽剂补充物，评估孢子的根除情况。
在红光照射下，10 分钟内，甲苯胺蓝 O（TBO）和亚甲蓝（MB）使营养细菌减少了>5 个对数菌落形成单位/mL。添加阳离子表面活性剂对光增敏剂的孢子根除没有显著影响（P>0.05）。然而，在 20 分钟的照射后，添加营养发芽混合物到 TBO 中可实现 6 个对数减少，同时为 MB 和吡咯红 Y 提供 1-2 个对数的孢子根除改善。
在存在表面活性剂和促进发芽剂的光激活光敏剂溶液提供了一种非常有效的方法来根除休眠和营养细菌。这些溶液可以为医疗保健中的高水平消毒和感染控制提供一种有用的替代传统化学剂的方法。
