正常人下呼吸道是无菌的，但老年性慢性阻塞性肺疾病（COPD）患者下呼吸道常有细菌寄生，由于受采集方法的影响，这些细菌在COPD急性发作时所起的作用过去一直没有很好的解释，而且以往用痰培养等方法对这些微生物的检查因易受日咽部细菌的污染而影响其可靠性，对临床治疗效果 Normal lower respiratory tract is sterile, but elderly patients with chronic obstructive pulmonary disease (COPD) lower respiratory tract bacteria often parasitic, due to the collection method, the role of these bacteria in acute exacerbations of COPD in the past has not been very Good explanation, but in the past with sputum culture and other methods of examination of these microorganisms due to susceptibility to pollution of the pharyngeal bacteria affect its reliability, the clinical treatment effect