Anti-biofilm activity of white horehound extract in catheter-associated infection

描述（由申请人提供）：金黄色葡萄球菌是所有细菌病原体中最突出的一种。耐药性的持续出现及其产生毒力因子和生物膜的能力导致社区和医院环境中的发病率和死亡率不断上升。金黄色葡萄球菌产生的生物膜极难根除，是难治性感染的令人厌倦的来源。生物膜增加了抗菌素治疗的耐药性，显然需要开发新的抗菌素治疗方法。本实验的重点是评估白苦根（Marrubium vulgare L., Lamiaceae）提取的天然产物治疗生物膜相关葡萄球菌感染的潜力。白苦薄荷是一种原产于地中海的野生草本薄荷。它是意大利南部补充和替代医学（CAM）框架中最重要的药用植物之一。特别是，该植物的煎剂被局部用于治疗几种类型的皮肤和软组织感染，其中许多与葡萄球菌感染有关。我已经证实白苦根的粗乙醇提取物在破坏葡萄球菌生物膜方面表现出显著的活性。本方案的实验部分分为四个目的：1)从白苦根中分离和分离生物活性化合物；2)评价白苦参化合物在葡萄球菌生物膜环境下的体外药效；3)评价活性化合物的体外细胞毒性；4)利用小鼠模型评估活性化合物对导管相关性葡萄球菌生物膜感染的体内预防和治疗效果。

DESCRIPTION (provided by applicant): Staphylococcus aureus is one of the most prominent of all bacterial pathogens. The continued emergence of drug resistance combined with its ability to produce virulence factors and biofilms has lead to increasing morbidity and mortality in both community and hospital settings. Biofilms produced by S. aureus are extremely difficult to eradicate and are the wearisome source of recalcitrant infection. Biofilms confer increased resistance to antimicrobial therapy and there is a clear need for the development of hovel antibiofilm therapies. The experimental focus of this proposal is to assess the potential of natural products extracted from white horehound (Marrubium vulgare L., Lamiaceae) for the treatment of biofilm-associated staphylococcal infection. White horehound is a wild herbaceous mint native to the Mediterranean. It is one of the most important medicinal plants used within the complementary and alternative medicine (CAM) framework of southern Italy. In particular, decoctions of the plant are topically applied for the treatment of several types of skin and soft tissue infection, many of which are related to staphylococcal infection. I have already established that crude ethanolic extracts of white horehound roots demonstrate remarkable activity in the disruption of established staphylococcal biofilms. The experimental component of this proposal is divided into four aims: 1) to fractionate and isolate bioactive compounds from white horehound; 2) to assess the in vitro efficacy of white horehound compounds in the context of staphylococcal biofilms; 3) to assess the in vitro cytotoxicity of active compounds; and 4) to assess the in vivo prophylactic and therapeutic efficacy of active compound(s) using murine models for catheter-associated staphylococcal biofilm infection. These aims will be addressed with bioassay-guided fractionation techniques, in which phytochemical methods (mechanism columns, HPLC, and LC/MS) will be combined with in vitro biofilm models. The cytotoxicity of active compounds will be assessed before the initiation of animal studies. A murine model will be used to assess the prophylactic capacity and therapeutic efficacy of these compounds in vivo. I believe that these experiments will ultimately lead to the identification of novel therapeutic agents for the prevention and treatment of staphylococcal catheter-associated biofilm infection. PUBLIC HEALTH RELEVANCE: Staphylococcus aureus causes devastating infections, and the current repertoire of antistaphylococcal drugs is insufficient. This proposal is aimed at investigating a popular plant-based traditional medicine for potential therapeutic applications in the prevention and treatment of biofilm infection.