Molecular Detection of Biofilms on Hip and Knee Implants

描述（由申请人提供）：美国每年进行约750，000例全髋关节和膝关节置换手术。由于人口老龄化，预计到2030年，这一数字将增加到250万。虽然大多数接受这些手术的人都有显着的好处，但大约3%的人需要再次手术，最常见的是人工关节感染（PJI）或假体无菌性松动。关节置换术失败的手术和医疗管理取决于是否存在感染。然而，对PJI进行微生物诊断具有挑战性。我们已经表明，原生关节感染诊断是不准确的PJI。与PJI相关的微生物存在于假体表面的生物膜中;因此，对假体表面进行采样的方法应改善PJI的诊断。我们的研究小组在新英格兰医学杂志上发表了一篇论文，表明我们开发的一种新技术，即对假体表面的生物膜进行采样，对于基于培养的PJI诊断，比传统的假体周围组织更敏感。虽然这种技术比传统方法更敏感，但它是基于培养的，因此周转时间长。此外，尽管与假体周围组织培养（即，78.5 vs. 60.8%，P < 0.001），仍有培养阴性病例。我们假设，分子微生物学的方法，针对生物膜细菌脱落的骨科假体，将更灵敏，更迅速地检测PJI相比，我们的文化为基础的方法。我们进一步假设，使用分子方法鉴定的生物膜中的细菌与某些病例的“无菌”人工关节失败相关，其发病机制尚未完全确定。我们正在开发和验证封闭系统快速实时聚合酶链反应测定法，共同靶向导致PJI的细菌，用于检测从骨科假体表面脱落的生物膜细菌。我们将前瞻性地评估这些检测方法，以证实与我们基于培养的方法相比，诊断PJI的灵敏度有所提高。我们将确定因PJI以外的原因进行的髋关节和膝关节置换术翻修的百分比，这些原因是翻修时存在先前未识别的细菌，如通过检测细菌生物膜的分子技术所检测到的，我们将评估此类病例的结局。我们的研究团队在PJI领域拥有丰富的翻译经验，并合作开展了多项研究。总的来说，我们在分子微生物学，细菌学，骨科感染和外科手术，医学生物膜，组织病理学和生物统计学方面拥有专业知识。这项研究的结果有望为PJI提供一种新的、快速的、敏感的分子诊断方法，并将评估微生物是否与无菌髋关节和膝关节置换术失败有关，这两者都将改变临床实践。

DESCRIPTION (provided by applicant): Approximately 750,000 total hip and knee replacement surgeries are performed each year in the United States. As a result of the aging population, these numbers are expected to increase to two and a half million by 2030. While the majority of those who undergo these procedures experience dramatic benefit, approximately three percent require re-operation, most commonly for prosthetic joint infection (PJI) or aseptic loosening of the prosthesis. Surgical and medical management of failed joint replacements depend on whether or not infection is present. However, making a microbiologic diagnosis of PJI is challenging. We have shown that native joint infection diagnostics are inaccurate for PJI. Microorganisms associated with PJI are found in biofilms on the prosthesis surface; accordingly, methods that sample the prosthesis surface should improve the diagnosis of PJI. Our research team published a manuscript in the New England Journal of Medicine, showing that a novel technique that that we have developed, which samples biofilms on the prosthesis surface, is more sensitive than conventional periprosthetic tissue for the culture-based diagnosis of PJI. Although this technique is more sensitive than conventional approaches, it is culture-based, and, accordingly has a long turnaround time. Further, despite improved sensitivity compared to periprosthetic tissue culture (i.e., 78.5 versus 60.8%, p < 0.001), there remain culture negative cases. We hypothesize that a molecular microbiologic approach, targeting biofilm bacteria dislodged from explanted orthopaedic prostheses, will more sensitively, and rapidly, detect PJI compared with our culture-based approach. We further hypothesize that bacteria in biofilms, identified using molecular methods, are associated with some cases of 'aseptic' failure of prosthetic joints, the pathogenesis of which is incompletely defined. We are developing and validating closed system rapid real-time polymerase chain reaction assays, collectively targeting bacteria which cause PJI, for detection of biofilm bacteria dislodged from the surface of orthopaedic prostheses. We will prospectively evaluate these assays to confirm improved sensitivity compared to our culture- based approach, for the diagnosis of PJI. We will determine the percentage of revision hip and knee arthroplasties performed for reasons other than PJI that have previously unrecognized bacteria present at revision, as detected by molecular techniques that detect bacterial biofilms, and we will assess the outcome of such cases. Our research team has extensive translational experience in the area of PJI and has collaborated on a number of studies. Collectively, we have expertise in molecular microbiology, bacteriology, orthopaedic infection and surgery, medical biofilms, histopathology, and biostatistics. Results of this study are expected to yield a novel, rapid, and sensitive molecular diagnostic for PJI, and will assess whether microbes are associated with aseptic hip and knee arthroplasty failure, both of which will transform clinical practice.