Abstract：
Pneumonia is a lower respiratory tract infection caused by the inability to clear pathogens from the lower airway and alveoli. Cytokines and local inflammatory markers are released, causing further damage to the lungs through the accumulation of white blood cells and fluid congestion, leading to pus in the parenchyma. The Infectious Diseases Society of America defines pneumonia as the presence of new lung infiltrate with other clinical evidence supporting infection, including new fever, purulent sputum, leukocytosis, and decline in oxygenation. Importantly, lower respiratory infections remain the most deadly communicable disease. Pneumonia is subdivided into three categories: (1) community acquired, (2) hospital acquired, and (3) ventilator associated. Therapy for each differs based on the severity of the disease and the presence of risk factors for methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa.
摘要：
肺炎是由于无法清除下气道和肺泡中的病原体而引起的下呼吸道感染。细胞因子和局部炎症标记物被释放，通过白细胞的积累和液体充血对肺部造成进一步的损害，导致薄壁组织有脓液.美国传染病学会将肺炎定义为存在新的肺部浸润，其他临床证据支持感染，包括新发烧,脓性痰，白细胞增多,和氧合下降。重要的是,下呼吸道感染仍然是最致命的传染病。肺炎分为三类：（1）社区获得性肺炎，(2)医院收购，和（3）呼吸机相关。根据疾病的严重程度和耐甲氧西林金黄色葡萄球菌或铜绿假单胞菌的危险因素的存在，每种疗法都有所不同。
