下呼吸道革兰阴性菌感染的病原学及耐药分析

【目的】了解本地区下呼吸道革兰阴性菌（G^-）感染者的病原学诊断及对常用抗生素的敏感情况。【方法】回顾性分析2002年1月至2004年12月本院下呼吸道感染住院患者痰标本细菌培养分离及药敏试验结果。【结果】分离率前五位的菌种分别为铜绿假单胞菌（34．8％）、不动杆菌（13．5％）、肺炎克雷伯菌（12．9％）、大肠埃希菌（12．3％）和阴沟肠杆菌（5．2％）。所有G^-均有较严重的耐药性，除头孢他啶外，对多数头孢三代药物耐药率高。耐药率较低的抗生素有亚胺培南、美洛培南、哌拉西林／他唑巴坦、头孢吡肟、左氟沙星。其中碳青霉烯类抗生素（亚胺培南、美洛培南）对下呼吸道G^-的敏感率在95％以上。本组分离的下呼吸道G^-对左氟沙星耐药率较低（33％），对阿米卡星的耐药率高（46％），与其他地区的报道存在较大差异。【结论】下呼吸道G^-感染的耐药是目前临床上面临的难题，值得进一步研究，应采用合理的手段降低耐药率的发生。

Study on the Distribution and Drug Resistance of Gram-negative Bacteria in Patients with Lower Respiratory Tract Infection

Objective]To investigate the distribution of drug resistance of gram-negative bacteria in patients with lower respiratory tract infection in Changde city.Methods]The results of sputum's culture and antimicrobial susceptibility of patients from 2002 to 2004 were reviewed.Results]The most common pathogens were Pseudomonas aeruginosa(34.8%),Acinetobacter spp(13.5%), Klebsiella pneumoniae(12.9%), Escherichia coli (12.3%),Enterobacter cloacae(5.2%). High drug-resistance rates were found among all strains of pathogens to the third generation cephalosporins except ceftazidime. The most sensitive agents against Gram negative organisms were carbopenems(Imipenem,Meropenem),with a susceptibility of more than 95%,followed by Piperacilline/Tazobactam, Cefepime and Levofloxacin. In this study, the drug-resistance rate among gram-negative bacteria from lower respiratory tract to Levofloxacin was 33%,while drug-resistance rate to amikacin was 46%,different from reports of other area.Conclusion]Drug-resistance is still a serious clinical problem. An unanimous effective strategy for the solution of this problem is urgently needed.