How Do a Few Attached Staphylococcus aureus Bacteria Evade Innate Immunity to Initiate Biofilm Infection on an Implanted Medical Device?

项目摘要/摘要 植入的医疗设备拯救了许多人的生命，提高了他们的生活质量。但就是这样 植入物仍然容易受到聚集在植入物上或附近的微生物的麻烦感染 生物膜中的装置。三十多年来在抗菌涂料和抗生素疗法方面的工作 未能提出有效的生物被膜感染解决方案，这表明研究人员一直在 遗漏了这块拼图中的重要一块。我们认为，预防种植体相关的关键 感染是更好地理解和协调先天免疫的最早阶段。在……里面 特别是，假设中性粒细胞在稀少污染的生物材料上缓慢募集 让一些细菌有时间成长为聚集体，这些聚集体受到保护，不会被杀死 被中性粒细胞感染并持续存在。在三个具体目标中，该项目将量化以下现象： 目的1.中性粒细胞在细菌污染的生物材料表面的募集时间。目标2.成长 中性粒细胞发现之前附着在非生物表面的细菌的动态。目标3.细菌和 中性粒细胞发现后的中性粒细胞命运。这些测量将由一个跨学科的 团队融合了定量生化工程、分子微生物学、免疫学、 整形外科、生物材料、数学和统计学。主要的模式细菌将是 金黄色葡萄球菌和动物模型都将在老鼠身上。四个互补实验 将使用的模型：1)细菌-人中性粒细胞相互作用的体外视频显微镜 稀疏接种的非生物表面；2)中性粒细胞的全动物成像和细菌动力学 皮下植入后；3)中性粒细胞单细胞分辨率活体成像- 皮下植入物上的细菌动力学，以及4)传统的皮下植入物模型 用于细胞因子/基因图谱、免疫细胞类型的分类和附加显微镜。 该项目将生成独特的数据集，强调量化、概率表征 植入后最初几个小时的宿主-病原体相互作用，可能是 防止生物被膜感染。这项工作将为制定新的战略打开大门 通过增加中性粒细胞数量或加快速度预防植入性医疗器械感染 将它们输送到受污染的植入物具有多个潜在优势：短期干预， 广谱适用性，消除了抗生素耐药性的担忧。

PROJECT SUMMARY/ABSTRACT Implanted medical devices have saved lives and improved the quality of life for many. But such implants remain vulnerable to troublesome infection by microorganisms that aggregate on or near the device in a biofilm. More than three decades of work on antimicrobial coatings and antibiotic therapies have failed to produce robust solutions to biofilm infection, suggesting that researchers have been missing an essential piece of this puzzle. We contend that the key to preventing implant-related infection is a better understanding and orchestration of innate immunity at the earliest stage. In particular, it is hypothesized that slow recruitment of neutrophils to a sparsely contaminated biomaterial gives some bacteria time to grow into aggregates, and that these aggregates are protected from killing by neutrophils and persist. In three Specific Aims, this project will quantify the following phenomena: Aim 1. Neutrophil recruitment times to bacteria-contaminated biomaterial surfaces. Aim 2. Growth dynamics of bacteria attached to an abiotic surface prior to neutrophil discovery. Aim 3. Bacterial and neutrophil fates post neutrophil discovery. These measurements will be made by an interdisciplinary team merging expertise in quantitative biochemical engineering, molecular microbiology, immunology, orthopedic surgery, biomaterials, and mathematics and statistics. The primary model bacterium will be Staphylococcus aureus and the animal models will all be in mice. Four complementary experimental models will be used: 1) in vitro video microscopy of bacteria-human neutrophil interactions on a sparsely inoculated abiotic surface; 2) whole animal imaging of neutrophil and bacterial dynamics following subcutaneous implantation; 3) intravital imaging with single cell resolution of neutrophil- bacteria dynamics on a subcutaneous implant, and 4) a conventional subcutaneous implant model to be used for cytokine/gene profiling, cataloging of immune cell types present, and additional microscopy. This project will generate unique data sets emphasizing quantitative, probabilistic characterization of the host-pathogen interaction in the first several hours after implantation, the likely window for preventing a biofilm infection from establishing. This work will open the door to new strategies for preventing infections on implanted medical devices by boosting neutrophil numbers or speeding up their delivery to the contaminated implant with multiple potential advantages: short-term intervention, broad spectrum applicability, and obviation of antibiotic resistance concerns.