目的　探讨老年人下呼吸道感染与痰病原菌分布关系。方法　 168例老年人下呼吸道感染患者 ,反复住院 2 16例次 ,定期进行痰培养 ,以连续≥ 2次或间隔≥ 3次痰培养为同一种病原菌为阳性结果。结果　痰培养 873例次 ,符合阳性结果 32 6例次 (37% ) ,其中革兰阳性球菌 5 0例次 (15 % ) ,革兰阴性杆菌 2 2 1例次 (67% )。绿脓杆菌对头孢三代及哌拉西林的耐药率 10 %～ 44 % ,肺炎克雷白杆菌对头孢三代及丁胺卡那霉素的耐药率 11%～ 37%。痰病原菌的检出率显示 :病情重的较高 ,院内感染高于院外感染。结论　老年人下呼吸道感染的病原菌以革兰阴性杆菌为主 ,而且对抗生素的耐药率有增加趋势 Objective To investigate the relationship between the lower respiratory tract infection and the distribution of sputum pathogens in the elderly. Methods A total of 168 elderly patients with lower respiratory tract infection were hospitalized repeatedly for 2 16 times. Sputum culture was carried out on a regular basis. Positive sputum culture was performed with ≥ 2 consecutive or ≥ 3 sputum cultures for the same pathogen. Results 873 sputum cultures were performed, of which 32 6 (37%) were positive, of which Gram-positive cocci was 50 (15%) and Gram-negative bacilli were 21 (67%). Pseudomonas aeruginosa three generations of cephalosporins and piperacillin resistance rate of 10% to 44%, Klebsiella pneumoniae three generations of cephalosporins and amikacin resistance rate of 11% to 37%. The detection rate of sputum pathogens shows that the disease is heavier and the nosocomial infection is higher than the nosocomial infection. Conclusions Gram-negative bacilli are the main pathogenic bacteria of lower respiratory tract infection in elderly people, and the rate of resistance to antibiotics increases