1995-2004年下呼吸道感染病原菌变迁

目的了解1995—2004年湘雅医院呼吸科下呼吸道感染住院患者病原菌及其药敏变迁情况。方法对呼吸病房下呼吸道感染住院患者痰菌（或支纤镜吸取分泌物）培养阳性标本结果进行回顾性统计分析。结果分离出细菌2158株，其中革兰阴性杆菌占84．9％，病原菌主要为铜绿假单胞菌、肺炎克雷伯菌、鲍曼不动杆菌和大肠埃希菌；革兰阳性球菌占15．1％，主要病原菌为金葡菌和肺炎链球菌。20世纪90年代中后期和2000年以后相比革兰阴性杆菌有所减少，而革兰阳性球菌有所增加。药敏试验结果提示主要革兰阴性杆菌对美罗培南、头孢哌酮-舒巴坦均较敏感。铜绿假单胞菌对阿米卡星耐药率也低，对头孢噻肟、头孢曲松耐药率较高；肺炎克雷伯菌对头孢他啶也较敏感，对头孢哌酮、头孢噻肟、头孢曲松耐药率较铜绿假单胞菌低；主要革兰阳性球菌对阿奇霉素、红霉素、青霉素及克林霉素耐药率均较高。其中金葡菌对万古霉素均敏感；肺炎链球菌对美罗培南、左氧氟沙星耐药率低。结论近10年下呼吸道感染病原菌以革兰阴性杆菌为主，但有逐渐减少的趋势。主要病原菌对部分抗菌药物的耐药率有逐渐增高的趋势，临床应合理应用抗菌药，以延缓细菌耐药性的产生。

Change of bacterial pathogens in lower respiratory tract infection during 1995-2004

Objective To investigate the change of distribution and antibiotic susceptibility of pathogenic bacteria isolated from inpatients with lower respiratory tract infection in Department of Respiratory Medicine during 1995-2004. Methods All the clinical isolates from sputum or secretion of lower respiratory tract from 1995 to 2004 were analyzed retrospectively. Antibiotic susceptibility was tested by Kirby-Bauer method. Results were interpreted according to NCCLS breakpoints. Results A total of 2 158 clinical isolates were collected, including 1 832 (84.9%) strains of gram-negative bacilli and 326 (15.1%) strains of gram-positive cocci. The most important gram-negative pathogens were Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumanii and Escherichia coli. The most common gram-positive cocci were Staphylococcus aureus and Streptococcus pneumoniae. The proportion of gram-positive microorganisms increased relatively since the year of 2000 as compared to the second half of 1990s, while the proportion of gram-negative microorganism decreased gradually. Most strains of gram-negative bacilli were susceptible to meropenem and cefoperazone-sulbactam. P. aeruginosa isolates were relatively susceptible to amikacin, but highly resistant to cefotaxime and ceftriaxone. The resistance of K. pneumoniae to ceftazidime, cefoperazone, cefotaxime and ceftriaxone were lower than that of P. aeruginosa. The major gram-positive isolates were highly resistant to azithromycin, erythromycin and clindamycin. All S. aureus isolates were susceptible to vancomycin. S. pneumoniae isolates were highly susceptible to meropenem and levofloxacin. Conclusions Gram-negative bacilli are still the leading pathogens in lower respiratory tract infection during the past 10 years in our Department of Respiratory Medicine, but there is a trend showing that the proportion of gram-negative isolates is decreasing. Antibiotic resistance becomes more prevalent in some major pathogens. Rational use of antibiotics is important for the containment of bacterial resistance.