How do biocides interact with bacterial membranes to disinfect?

杀菌剂如何与细菌膜相互作用来消毒？

• 批准号: ST/Y000552/1
• 负责人: Jian Lu
• 金额: $ 6.9万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FY000552%2F1
• 关键词: How; do; biocides; interact; bacterial

The growing Hospital Acquired Infections as well as Covid infections transmitted from contaminated solid surfaces over the past few years have challenged our ability to fight harmful microorganisms effectively. Cationic surfactants (quaternary nitrogen compound or abbreviated as quats) are one of the most widely used disinfectants. Despite their intensive use, little is actually known about how cationic surfactants interact with microbial membranes and kill the pathogens in the presence of other additives, e.g. hard water ions, nonionic surfactants. This situation limits our ability to design and formulate effective disinfectants. Weak or ineffective disinfectants, when used in hard surface cleaning (surgical devices, beds and airing systems and even food and diary processing facilities), could lead to outbreaks that could cost millions and, in some cases, have casualties. A formulated cationic quat disinfectant cleaning product often contains nonionic surfactants to provide cleaning efficacy. Despite decades of research and development, little is known about the role of the nonionics in disinfection. This lack of understanding creates a vacuum when new products are developed. Without this vital information about the interfacial biocidal action of such blends it is difficult to balance the levels of quats in product formulation.Biocidal quat molecules can bind (and usually do) to microbial membranes via strong electrostatic attraction and kill pathogens by structural disruption and membrane leakage. This mode of action is well supported by the rugged or disrupted surfaces of bacteria and fungi viewed from imaging studies such as scanning electron microscopy and confocal microscopy. Membrane disruptions have also been monitored by membrane permeation probes and fluorescence detection, zeta potential measurements and dynamic light scattering using lipid membrane models, such as spread lipid monolayer, supported lipid bilayer and small unilamellar vesicles (SUVs). High consistency to real microbial measurements validates the model membrane approaches. However, current techniques do not have the sensitivity or resolution to structural changes within the membrane which is typically in the region 1-5 nm. Lack of capability to follow structural changes during a biocide binding makes it difficult to distinguish one biocide from another or explore the impacts of different membranes. Neutron reflection (NR) and scattering (SANS) are about the only techniques that offer the insights into the structural changes across lipid membranes upon quat binding, with and without nonionic surfactant. Successful demonstration of the neutron experiments in this exploratory project replies on (a) input of neutron expertise in the running of the neutron experiments, synthesis of the deuterated surfactants and data analysis and interpretation from the ISIS team, (b) the expertise of antimicrobial work and selection of model lipid membranes from the Manchester team and (c) the active participation of Arxada in relating model interfacial studies to real quat formulations. The project teams have worked together to devise the challenging workplan that will be delivered by a highly able PDRA, Dr Mingrui Liao, who has already had prior knowledge of the quat biocides in his current PDRA work and neutron experiments from his PhD research on antimicrobial peptides. Successful outcomes from this project will form a strong basis for the collaborating teams to send joint grant applications to BBSRC and EU to engage in this new area of research by seeking more systematic neutron experiments. The teams will also publish their results in leading international journals such as JACS and Nat Commun.

过去几年，医院获得性感染以及由受污染的固体表面传播的新型冠状病毒感染不断增加，挑战了我们有效对抗有害微生物的能力。阳离子表面活性剂（季氮化合物或简称季铵盐）是应用最广泛的消毒剂之一。尽管它们被广泛使用，但实际上很少有人知道阳离子表面活性剂如何与微生物膜相互作用并在其他添加剂（例如硬水离子，非离子表面活性剂）存在下杀死病原体。这种情况限制了我们设计和配制有效消毒剂的能力。弱或无效的消毒剂，当用于硬表面清洁（手术器械，床和通风系统，甚至食品和乳制品加工设施）时，可能导致爆发，可能造成数百万美元的损失，在某些情况下，造成人员伤亡。配制的阳离子季铵消毒剂清洁产品通常含有非离子表面活性剂以提供清洁功效。尽管经过几十年的研究和开发，人们对非离子表面活性剂在消毒中的作用知之甚少。这种缺乏了解的情况在开发新产品时造成了真空。如果没有这类共混物界面杀菌作用的重要信息，就很难平衡产品配方中季铵化合物的含量。杀菌季铵化合物分子可以通过强大的静电吸引力与微生物膜结合（通常如此），并通过结构破坏和膜泄漏杀死病原体。这种作用模式得到了细菌和真菌粗糙或破裂表面的很好支持，这些表面可以通过扫描电子显微镜和共聚焦显微镜等成像研究观察到。膜破裂也已监测膜渗透探针和荧光检测，zeta电位测量和动态光散射使用脂质膜模型，如扩展脂质单层，支持脂质双层和小单层囊泡（SUV）。与真实的微生物测量的高度一致性验证了模型膜方法。然而，目前的技术对膜内的结构变化不具有灵敏度或分辨率，其通常在1-5 nm的范围内。在杀生物剂结合期间缺乏跟踪结构变化的能力使得难以区分一种杀生物剂与另一种杀生物剂或探索不同膜的影响。中子反射（NR）和散射（SANS）是唯一的技术，提供洞察跨脂质膜的结构变化后，季结合，有和没有非离子表面活性剂。这一探索性项目中子实验的成功演示对以下方面作出了答复：（a）在中子实验的运行、氘代表面活性剂的合成以及ISIS团队的数据分析和解释方面提供了中子专门知识，（B）曼彻斯特团队的抗菌工作和模型脂质膜选择的专业知识，以及（c）Arxada积极参与将模型界面研究与真实的季铵化合物配方联系起来。项目团队共同设计了具有挑战性的工作计划，该计划将由一位非常有能力的PDRA廖明锐博士提供，他在目前的PDRA工作和中子实验中已经了解了季铵生物杀灭剂的知识，他在抗菌肽方面的博士研究。该项目的成功成果将为合作团队向BBSRC和欧盟提交联合资助申请奠定坚实的基础，以便通过寻求更系统的中子实验来参与这一新的研究领域。研究小组还将在JACS和Nat Commun等国际领先期刊上发表他们的研究结果。