本文以气管切开 (或插管 )病人为研究对象 ,用防污染标本刷 (PSB)采集标本 ,用质粒DNA图谱、酶切图谱、全基因组DNA稀有位点酶切脉冲电场电泳 (GM PFGE)等基因分型方法 ,前瞻性观察NP的发生情况。结果 11名患者有逆行感染存在 (发生率为 10 2 % ,占感染病例的 2 2 % ) ,即在胃液分离出病原菌一、二天后 ,PSB在咽部及下呼吸道也检出相同的细菌 ,应用上述分子生物学技术进行同源性分析 ,聚类分析相似系数为 10 0 %。将美兰经胃管注入病人胃内 ,而后在咽部及下呼吸道也有蓝色分泌物检出。证明的确存在胃→咽→下呼吸道的逆行感染途径 In this study, tracheotomy (or intubation) patients were selected as the research object. Specimens were collected with anti-contamination brush (PSB). Plasmid DNA profiles, enzyme digestion patterns and whole-genome DNA restriction enzyme- And other genotyping methods, prospective observation of the occurrence of NP. Results 11 patients had retrograde infection (the incidence was 102%, accounting for 22% of the infected cases). That is, one or two days after the pathogen was isolated from gastric juice, PSB also detected the same bacteria in the pharynx and lower respiratory tract, Homology analysis was performed using the above molecular biology techniques. The similarity coefficient of cluster analysis was 100%. Meilan will be injected into the stomach by the stomach, and then in the throat and lower respiratory tract are also blue secretions detected. Proves the existence of the stomach → pharynx → retrograde infection of the lower respiratory tract