Modifying and Delivering Antimicrobials to Prevent Orthopaedic Implant Infections

 描述(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，根除感染通常需要手术移除植入物，这是一种奢侈品，因为植入物提供了必要的结构支持。这些感染也是一项重大的公共卫生支出，每年要额外支出80多亿美元。目前的种植体涂层技术在当地存在 提供抗生素，试图防止细菌感染。这些方法实现了有限的翻译，原因是：1)无法实现超过抗生素必要最低抑制浓度的持续释放；2)增加了额外的惰性支架，本身就是细菌黏附和生物膜形成的表面；3)目前抗生素对组成生物膜状态细菌的缓慢生长的细菌细胞的有效性有限。为了解决这些问题，这项提议将调查两个概念上的创新假设，探索宿主和细菌与新型抗菌剂(活性释放抗生素涂层和针对慢复制细菌的重新设计的抗生素)的刺激之间的关系，这两个假设使用新的诊断工具来同时评估感染和宿主对感染的免疫反应：1)双RNA测序；2)非侵入性体内生物发光成像。该提案旨在开发一种组合的被动-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，将沉积额外的抗生素。这种植入物涂层将浸入i)常用抗生素以及ii)一种新的、重新设计的抗生素，它专门针对组成生物膜的衰老细菌。这些植入物将用于一种新的植入物感染的体内小鼠模型1]以评估有效性，2)在亚抑制和抑制性抗生素剂量下激发宿主PMN和细菌的转录反应。最后，将使用骨整合分析技术对建议中开发的涂层的生物相容性进行评估。综上所述，这项提议将利用现有的机构基础设施和人力资本，开展新颖、巧合和相互依赖的宿主免疫细胞：细菌成像和深RNA测序技术，以研究宿主免疫和感染细菌对抗菌素的反应。如果成功，这个项目将：i)为PMN的纵向研究奠定基础：细菌与其他细菌链相互作用；ii)为大动物临床前研究一种新的涂层和 3)扩大我们对细菌和宿主对抗生素反应的了解，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.