社区获得性肺炎,仍是导致发达国家住院治疗的主要原因以及死亡的常见原因,在美国该病的死亡率是仅次于心血管病、肿瘤、脑血管病、慢性气管疾病而居第5位。但有关其在固定人群中的发生率和危险因素的研究报道甚少。有利于病原微生物进入呼吸道并定居、繁殖及损伤呼吸防卫机制 Community-acquired pneumonia is still the leading cause of hospitalization in developed countries and a common cause of death in the United States, with the second most common cause of death in the United States after cardiovascular disease, cancer, cerebrovascular disease and chronic airway disease . However, little is known about the incidence and risk factors in the fixed population. Is conducive to pathogenic microorganisms into the respiratory tract and settle, reproductive and injury respiratory defense mechanism