Defining mechanisms of antiseptic tolerance against skin microbiota

防腐剂对于预防人类和动物感染至关重要，因为通常在皮肤上发现的细菌是感染的主要原因，当它们通过皮肤屏障的破坏或通过出于各种医疗原因插入的导管进入血液时。特别是一组葡萄球菌（与MRSA有关），称为“凝固酶阴性葡萄球菌（CoNS）”，生活在皮肤上，并在动物和人类，特别是早产儿中引起严重感染。目前预防感染的措施依赖于使用防腐剂从皮肤上去除病原体，从而阻止它们引起感染。临床上使用的两种主要防腐剂：氯己定和奥替尼定，其中氯己定也广泛用于动物。总之，这些药物在预防感染方面至关重要。最近有多份报告记录了CoNS的鉴定，这些CoNS对防腐剂具有异常的耐受性，这引发了人们对它们可能对防腐剂产生耐药性的担忧，这将导致人类和动物感染风险增加。尽管氯己定和奥替尼定广泛使用，但人们对它们的工作原理以及细菌如何对它们产生耐药性知之甚少。本文提出的研究将研究这些药物如何起作用，并探索是否会发生防腐剂耐药性，如果是这样，突变细菌是否也会因此对抗生素产生交叉耐药性。我们最近从两个新生儿重症监护病房的婴儿皮肤中收集了1250个CoNS。一个在英国使用氯己定，一个在德国使用奥替尼定。我们已经看到两个单位之间的防腐剂耐受性存在明显差异。在这项研究中，我们将解码我们收集的所有菌株的基因组，并将这些信息与防腐剂敏感性进行比较。这将使我们能够确定任何导致分离株耐防腐剂的遗传变化。我们将把联合收割机这种方法与实验室研究相结合，在实验室研究中，我们将选择分离株暴露于每种防腐剂，并研究它们如何变得耐受。重要的是，我们已经开发了一个人类皮肤模型，我们可以用它来做这将是一个现实的代理在真实的世界中使用。同样，我们将对任何耐药突变体的基因组进行测序。这种对耐药菌株和突变体的遗传分析将有助于我们了解与防腐剂耐药性有关的基因。我们还将观察将分离株暴露于防腐剂是否会改变它们的抗生素耐药性，从而导致更难治疗的感染。申请人在研究消毒剂，细菌基因组学和皮肤对感染的反应方面有很强的背景，我们将在这里使用这些技能。我们产生的数据将被使用并与临床和兽医同事分享，以告知如何最好地在动物和人类中使用防腐剂，重点是早产儿。我们将能够评估细菌对两种主要防腐剂中的任何一种产生耐药性的风险是否存在差异，这可以指导最佳实践。我们还将产生有关这两种药物工作机制的有用信息，这将有助于未来新防腐剂的开发。

Antiseptics are critical to prevention of infection in humans and animals as bacteria normally found on the skin are the major causes of infections when they gain access to the blood via breakage of the skin barrier or via catheters inserted for various medical reasons. In particular a group of staphylococci (related to MRSA) known as 'coagulase negative staphylococcus (CoNS)' live on skin and cause serious infections in animals and humans, particularly premature babies. Current measures to prevent infection rely on the use of antiseptics to remove pathogens from the skin and hence stop them causing infection. Two major antiseptics are used clinically:chlorhexidine and octenidine, with chlorhexidine also being widely used in animals. Together, these agents are crucial in preventing infections. Recently there have been multiple reports documenting the identification of CoNS which are unusually tolerant to antiseptics prompting worries that they may become resistant to antisepsis which would result in increased infection risk to humans and animals.Despite the widespread use of chlorhexidine and octenidine, little is known about how they work and how bacteria could develop resistance to them. The study proposed here will study how these agents work and explore whether antiseptic resistance can occur and if so whether mutant bacteria also become cross-resistant to antibiotics as a result. We have recently assembled a collection of 1250 CoNS from the skin of babies from two neonatal intensive care units. One in the UK where chlorhexidine is used and one in Germany where octenidine is used. We have seen there are clear differences in antiseptic tolerance between the two units. In this study we will decode the genomes of all the strains we have collected and compare this information with antiseptic susceptibility. This will allow us to identify any genetic changes that cause antiseptic tolerance in the isolates. We will combine this approach with laboratory studies where we will expose selected isolates to each antiseptic and study how they become tolerant. Importantly, we have developed a human skin model we can use to do this which will be a realistic proxy for use in the real world. Again, we will sequence the genomes of any resistant mutants. Together this genetic analysis of resistant isolates and mutants will help us understand the genes involved in antiseptic resistance. We will also see if exposing isolates to the antiseptics makes them change their antibiotic resistance which could result in harder to treat infections.The applicants have a strong background in studying disinfectants, bacterial genomics and skin responses to infection and we will use those skills here. The data we produce will be used and shared with clinical and veterinary colleagues to inform how best to use antiseptics in animals and humans with a focus on premature babies. We will be able to assess if there is a difference in the risk of bacteria becoming resistant to either of the two major antiseptics which can guide best practice. We will also generate useful information about the mechanisms by which both agents work which will help development of new antiseptics in future.