Modifying and Delivering Antimicrobials to Prevent Orthopaedic Implant Infections

 描述（由申请人提供）：骨科手术后的感染是灾难性的。植入物很容易被细菌定植，并且根除感染通常需要手术移除植入物，这对于植入物提供基本结构支撑的患者来说是不可能的。这些感染也是一项主要的公共卫生开支，每年花费超过80亿美元的额外支出。现有的植入物涂层技术局部 提供抗生素，试图防止细菌感染。这些方法已经实现了有限的转化，因为i）不能实现抗生素在必需的最小抑制浓度以上的持续释放，ii）添加额外的惰性支架，其本身是用于细菌粘附和生物膜形成的表面，和iii）当前抗生素针对包含生物膜状态细菌的缓慢生长的细菌细胞的有限有效性。为了解决这些问题，本提案将调查两个概念上创新的假设，探索宿主和细菌与新型抗菌剂的激发的关系（主动释放抗生素涂层和靶向缓慢复制细菌的再工程化抗生素），使用新的诊断工具，其同时评估感染和宿主对感染的免疫应答：1）双重RNA测序;和2]非侵入性体内生物发光成像。该提案旨在开发一种组合被动-主动释放聚合物涂层，当受到假体周围感染的酸性环境挑战时，该涂层将存款额外的抗生素。该植入物涂层将浸渍有i）常用的抗生素以及ii）特异性靶向包含生物膜的衰老细菌的新型再工程抗生素。这些植入物将用于植入物感染的新型体内小鼠模型中，1]以评估疗效，2]以亚抑制和抑制抗生素剂量激发宿主PMN和细菌的转录组学应答。最后，将使用骨整合分析技术评估提案中开发的涂层的生物相容性。总的来说，该提案将利用现有的机构基础设施和人力资本，开展新的、巧合的和相互依存的宿主免疫细胞：细菌成像和深度RNA测序技术，以研究宿主免疫和感染细菌对抗菌剂的反应。如果成功，该项目将i）为PMN的纵向研究奠定基础：细菌与其他细菌链的相互作用，ii）为新型涂层和新型抗菌剂的大型动物临床前研究提供基础。 抗菌剂，和iii）拓宽我们对细菌和宿主对抗生素的反应的理解，为未来的抗菌治疗奠定基础。

 DESCRIPTION (provided by applicant): Infections after orthopaedic surgery are catastrophic. Implants are easily colonized by bacteria, and eradication of infection often requires surgical removal of the implant, a luxury not available for patients in whom the implant provides essential structural support. These infections are also a major public health expense, costing more than $8 billion of additional spending per year. Current implant coating technologies exist that locally deliver antibiotics, attempting to prevent bacterial infection from taking hold. These methods have achieved limited translation because of i) the inability to achieve sustained release above necessary minimum inhibitory concentrations of the antibiotic, ii) the addition of an additional inert scaffolding that is itself a surface for bacterial adhesion and biofilm formation, and iii) limited effectiveness of current antibiotics against slow-growing bacterial cells that comprise biofilm-state bacteria. In order to address these issues, this proposal will investigate two conceptually innovative hypotheses that probe the relationship of host and bacteria with the provocation of novel antimicrobials (active-release antibiotic coatings and re-engineered antibiotics targeting slow-replicating bacteria) using novel diagnostic tools that coincidentally assess the infection and the host immune response to the infection: 1] dual RNA sequencing; and 2] non-invasive in vivo bioluminescent imaging. The proposal aims to develop a combination passive-active-release polymer coating that will deposit additional antibiotic when challenged by the acidic environment of periprosthetic infection. This implant coating will be impregnated with i) commonly used antibiotics as well as ii) a novel, re-engineered antibiotic that specifically targets the senescent bacteria that comprise biofilms. These implants will be employed in a novel in vivo mouse model of implant infection 1] to assess efficacy and 2] in sub-inhibitory and inhibitory antibiotic doses to provoke a transcriptomic response from host PMNs and bacteria. Finally, coatings developed in the proposal will be assessed for biocompatibility using techniques of osseointegration analysis. Taken together, this proposal will capitalize on existing institutional infrastructure and human capital to undertake novel, coincidental and interdependent host immune cell: bacterium imaging and deep RNA sequencing technologies to investigate host immune and infecting bacterial responses to antimicrobials. If successful, this project will i) set the stage for longitudinal studies of PMN: bacteria interaction with other strans of bacteria, ii) provide a basis for large animal pre-clinical studies of a novel coating and novel antimicrobial agent, and iii) broaden our understanding of bacterial and host response to antibiotics, laying the groundwork for future antimicrobial therapies.