呼吸机相关性肺炎病原菌分布及其耐药性分析

Distribution and Drug-resistance of Pathogens in Patients with Ventilator-associated Pneumonia

目的 明确呼吸机相关性肺炎（VAP）病原菌的流行分布及耐药特点。方法 对气管切开并实施机械通气〉48h的261例患者下呼吸道分泌物，进行细菌定量培养及抗菌药物敏感性测定。结果 从气管切开至发生VAP的时间为3～126d，平均18．2d；发生VAP92例，发生率为35．2％，死亡率为35．9％；92例VAP患者下呼吸道分泌物培养出病原菌276株，病原菌种分布：革兰阴性杆菌170株，占61．6％，主要为假单胞菌属、不动杆菌属、克雷伯菌属、肠杆菌属；革兰阳性球菌57株，占20．6％，主要为金黄色葡萄球菌、表皮葡萄球菌、肠球菌属，真菌感染占17．8％，主要为假丝酵母菌属；各类病原菌混合感染者88．0％，主要病原菌药敏试验结果，革兰阴性杆菌对亚胺培南总敏感性最高，其次为头孢哌酮／舒巴坦、阿米卡星、环丙沙星、替卡西林／克拉维酸、头孢他啶，对氨苄西林、第二代头孢菌素、头孢噻肟、头孢曲松则有较高的耐药性；金黄色葡萄球菌耐药现象严重，对青霉素、苯唑西林的耐药率分别达100．0％、91．3％，但对万古霉素、替考拉宁尚敏感。结论 VAP的主要病原菌为革兰阴性杆菌且存在较严重的耐药现象，混合感染现象严重，应引起临床高度重视。

OBJECTIVE To investigate the prevalence and the drug-resistance of pathogens in patients with ventilator-associated pneumonia （VAP）. METHODS The secretion of lower respiratory tract of 261 patients receiving tracheostomy and mechanical ventilation for more than 48 hours was cultured with a quantitative method and their antibiotic susceptibility was detected by standard K-B methods. RESULTS The onset time of VAP was 3-126 days （means 18. 2 days） after using mechanical ventilation. The incidence of VAP was 35. 2%. The mortality of VAP was 35. 9%. Gram-negative bactilli （GNB） were the main pathogens in VAP. Among 276 strains of pathogens collected, the GNB occupied 61.6%, the Gram-positive bacteria （GPB） were 20. 6%, and the fungi were 17.8%. Among the GNB, Pseudomonas, Acinetobacter, Klebsiella and Enterobacter were the main pathogens. Among the GPB, Staphylococcus aureus, S. epidermidis and Enterococcus were the main pathogens. Meticillin-resistanet S. aureus （MRSA） accounted for 91. 3% in S. aureus. Candida albicans was the main fungus. The mixed infections attained to 88.0%. The antibiotic susceptibility test results showed that GNB was highly susceptible to imipenem, cefoperazone/sulbactam, amikacin, ciprofloxacin, ticarcillin/clavulanic acid and ceftazidime in proper order. There was a high resistantce to ampicillin, second generation of cephalosporins, cefotaxime and ceftriaxone in GNB. S. aureus had severe drug-resistance to penicillin and oxacillin but was still highly susceptible to vancomycin and teicoplanin. CONCLUSIONS GNB are still the most important pathogens in VAP and have multiple drug-resistance. Mixed infections are severe that should be paid much attentions by clinic.