医院获得性鲍曼不动杆菌肺炎六例微生物学及临床观察

目的探讨医院获得性鲍曼不动杆菌肺炎患者临床微生物学特点和治疗转归。方法回顾性调查2005年1～8月白求恩国际和平医院经分子生物学方法证实的6例医院获得性产PER-1型超广谱13内酰胺酶（ESBL）鲍曼不动杆菌肺炎患者的临床资料。用脉冲场凝胶电泳检测6株鲍曼不动杆菌的同源性，聚合酶链反应分析相关耐药基因。结果6株鲍曼不动杆菌中5株仅对亚胺培南敏感，4株对美罗培南敏感。脉冲场凝胶电泳将其分为A1型2株，A2～如型各1株，携有β内酰胺酶blaPER-1基因，同时blaTEM-1型基因、耐消毒剂磺胺药物基因（qacEΔ1-sull）和1类整合子酶基因（intll）阳性，其中3株氨基糖苷类修饰酶基因aac（3）-I、aac（6’）-I同时阳性，2株aac（3）-I、ant（3”）-I同时阳性，1株aac（3）-I单独阳性。6例患者均患有严重的基础疾病，使用过呼吸机；检出鲍曼不动杆菌前15d内应用过广谱抗菌药物；经使用碳青霉烯类和（或）头孢哌酮／舒巴坦抗感染治疗，3例临床好转，3例死亡。结论6株产PER-1型ESBL鲍曼不动杆菌具有高度同源性，耐药基因复杂，其所引起的医院获得性肺炎临床预后差。

Microbiology and clinical analysis of six cases of hospital-acquired pneumonia caused by Acinetobacter baumannii

OBJECTIVE: To study the microbiology, clinical features and treatment outcomes of hospital-acquired pneumonia (HAP) caused by Acinetobacter baumannii. METHODS: Six cases of HAP, caused by Acinetobacter baumannii producing PER-1 type extended-spectrum beta-lactamase verified by molecular biological methods, were studied in Bethune International Peace Hospital, from January to August 2005. Clinical data were collected and analyzed. Pulsed-field gel electrophoresis (PFGE) were used to analyze the homology of these strains. The genes of beta-lactamase (BLA), aminoglycoside-modifying enzymes (AME), resistant to disinfectant-sulfanilamide (qacEDelta1-sul1), and class 1 integrase (intl1) were analyzed using PCR and verified by DNA sequencing. RESULTS: Among these 6 strains of Acinetobacter baumannii, five were susceptible only to imipenem, and 4 were susceptible to meropenem. The PFGE types identified from these isolates were A1 (n=2) and A2-A5 (n=1, respectively). They all were positive for PER-1, TEM-1, and genes of qacEDelta1-sull and intl1. Three of them harbored genes of aac (3)-I and aac (6')-I. Two had aac (3)-I and ant (3')-I. One had aac (3)-I. All the patients had severe underlying diseases, and had received mechanical ventilation. They all had received broad spectrum antibiotics within 15 days before Acinetobacter baumannii were identified. Although carbapenem and/or cefoperazone/sulbactam had been used, only 3 patients survived. CONCLUSION: The 6 PER-1 type extended-spectrum beta-lactamase-producing Acinetobacter baumannii isolates were closely related and had complex mechanisms of drug resistance. The prognosis of patients infected by them was poor.