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

项目总结/摘要 植入的医疗设备挽救了许多人的生命，提高了他们的生活质量。但这样 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。在抗菌涂层和抗生素疗法方面的工作超过三十年 未能产生生物膜感染的强大解决方案，这表明研究人员一直在 这其中缺少了一个重要的部分我们认为，防止植入相关疾病的关键 感染是在最早阶段更好地理解和协调先天免疫。在 特别地，假设中性粒细胞缓慢募集到稀疏污染的生物材料中， 使一些细菌有时间生长成聚集体，并且这些聚集体被保护而不被杀死， 中性粒细胞和持续。在三个具体目标中，该项目将量化以下现象： 目标1.细菌污染的生物材料表面的神经元募集时间。目标2.增长 在发现中性粒细胞之前，细菌附着在非生物表面的动力学。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。主要的模型细菌将是 金黄色葡萄球菌和动物模型将全部在小鼠中。四互补实验 将使用以下模型：1）在体外视频显微镜下观察细菌-人中性粒细胞相互作用， 稀疏接种的非生物表面; 2）中性粒细胞和细菌动力学的整体动物成像 皮下植入后; 3）中性粒细胞的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/基因分析、存在的免疫细胞类型的编目和额外的显微镜检查。 该项目将产生独特的数据集，强调定量，概率表征， 植入后最初几个小时内的宿主-病原体相互作用， 防止生物膜感染的建立。这项工作将为新的战略打开大门， 通过增加中性粒细胞数量或加速植入式医疗器械的感染 将它们输送到受污染的植入物具有多个潜在的优点：短期干预， 广谱适用性和避免抗生素耐药性问题。

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.