Chicago Community-Acquired Pneumonia Consortium II

社区获得性肺炎(CAP)和流感是第八大最常见的主要疾病，也是 在美国是次要死因。信息表明，CAP的病因和可能的频率 与上次疾控中心赞助的基于人群的研究相比发生了变化。甚至连CAP的定义都经历了 修订，排除了一组新定义的医疗保健相关肺炎(HCAP)。 不幸的是，现在缺乏适当的以人群为基础的病原体特异性研究来定义HCAP 引起了极大的争议。相反，分子诊断技术的发展，如 尿抗原检测和聚合酶链式反应(PCR)检测细菌和病毒基因，还没有 仅使病因学记录比基于培养的方法更准确，但在 更大比例的案例。所有这些因素汇聚在一起，需要以当代人口为基础 根据准确的病因学诊断估计CAP的发病率。 为了响应这一需求和由此带来的CDC资金机会，我们开发了一个由三个人组成的财团 芝加哥城市医院在18个月内招募1500名成人CAP患者。结合使用 之前在相同中心进行的研究使用了几乎相同的方案，可以在3年内进行准确的估计。 准确的基于人口的发病率估计需要将城市人口与多样性包括在内 入院患者的种族/民族、社会经济和获得医疗保健的特征 医院。到医院就诊的肺炎患者的几个亚组被排除在 目前疾控中心的研究，如最近出院的情况。由于这些患者通常使用ICD-9编码 CAP代码，它们会影响我们的事故计算。因此，我们将扩大这方面的纳入标准 招募这些患者的建议，期望分子诊断工具将证明 他们肺炎的百分比是由常见的CAP病原体引起的。我们还将解决有关以下问题的关切 社区获得性耐甲氧西林金黄色葡萄球菌(CA-MRSA)肺炎发病率增加。 微生物病原学将通过广泛的诊断测试来确定，包括常规使用尿抗原 检测、配对血清学和一系列疾控中心批准的聚合酶链式反应检测。流感和细菌的共同作用 将通过聚合酶链式反应、培养和配对血清学积极探索感染情况。全血定量聚合酶链式反应 肺炎球菌基因和普通细菌16S核糖体基因的定量聚合酶链式反应将增加诊断 敏感度。确认定量聚合酶链式反应与死亡率、感染性休克和器官衰竭相关将面临挑战。 传统的教条认为，这些并发症是由于宿主的反应，而不是细菌因素。 我们的数据结合其他参与中心的数据将提供更准确的当代 肺炎发病率和病原学评估。结果将为未来有关诊断的决策提供信息 测试、经验性抗生素治疗以及接种疫苗的机会和其他预防战略。

Community-acquired pneumonia (CAP) and influenza are the 8th most frequent primary and an important secondary cause of death in the US. Information suggests that etiology and possibly frequency of CAP have changed since the last CDC-sponsored population-based study. Even the definition of CAP has undergone revision, with exclusion of a group with the newly-defined healthcare-associated pneumonia (HCAP). Unfortunately, lack of an appropriate population-based pathogen-specific study to define HCAP has now resulted in significant controversy. Conversely, developments in molecular diagnostic techniques, such as urinary antigen testing and polymerase chain reaction (PCR) detection of bacterial and viral genes, have not only made documentation of etiology more accurate than culture-based methods but define etiology in a greater proportion of cases. All these factors coalesce on the need for a contemporary population-based estimate of CAP incidence based on an accurate etiologic diagnosis. In response to this need and the resultant CDC Funding Opportunity, we developed a consortium of three urban Chicago hospitals to recruit 1500 adult CAP patients over an 18 month period. Combining with a previous study at the same centers using a nearly identical protocol will allow accurate estimates over >3years. An accurate population-based estimate of incidence requires inclusion of an urban population with the variety of racial/ethnic, socioeconomic, and access to healthcare characteristics seen in patients admitted to these hospitals. Several subgroups of patients presenting to the hospital with pneumonia are excluded from the current CDC study, such as recent hospital discharges. Since these patients are routinely coded with ICD-9 CAP codes, they will impact our incidence calculations. We will therefore expand inclusion criteria for this proposal to recruit these patients, expecting that molecular diagnostic tools will demonstrate that a high percentage of their pneumonias are caused by usual CAP pathogens. We will also address concern regarding an increased incidence of community-acquired methicillin-resistant S. aureus (CA-MRSA) pneumonia. Microbial etiology will be determined by extensive diagnostic testing, including routine use of urinary antigen detection, paired serology, and a battery of CDC-approved PCR assays. The role of influenza and bacterial co- infection will be aggressively explored with PCR, culture, and paired serology. Whole blood quantitative PCR (qPCR) of a pneumococcal gene and a generic bacterial 16s ribosomal gene will increase diagnostic sensitivity. Confirmation that qPCR correlates with mortality, septic shock, and organ failure will challenge conventional dogma that these complications are due to the host response rather than bacterial factors. Our data combined with that of other participating centers will provide a more accurate contemporary assessment of pneumonia incidence and etiology. Results will inform future decisions regarding diagnostic testing, empirical antibiotic therapy, and the opportunities for vaccination and other prevention strategies.