重症监护病房鲍曼不动杆菌耐药性与分子流行病学研究

Antibiotic resistance profile and molecular epidemiology of Acinetobacter baumannii in intensive care unit

目的了解某一教学医院神经外科重症监护病房(ICU)临床和环境鲍曼不动杆菌分离株的耐药性与分子流行特征。方法采用琼脂稀释法检测该医院神经外科ICU临床患者分离菌27株与同期病房环境分离菌28株对16种常用抗菌药物的药敏试验;采用脉冲场凝胶电泳(PFGE)方法对鲍曼不动杆菌进行分子分型,采用多位点序列分型(MLST)技术,聚合酶链反应(PCR)扩增7个管家基因片段,测序并比较分析全部菌株的等位基因谱。结果 ICU分离27株鲍曼不动杆菌除对黏菌素和替加环素全部敏感外,对其他抗菌药物耐药率高,对米诺环素耐药率较低,为25.9%,其次为头孢哌酮-舒巴坦和亚胺培南,分别为51.9%和59.3%,其他抗菌药物耐药率均大于70%。环境分离28株鲍曼不动杆菌对抗菌药物较敏感。27株ICU分离菌株PFGE分为4个主要型别,MLST分为5个ST型;28株环境分离株可分为多种不同基因型别。结论在PFGE分型中,A型克隆株为临床菌株和环境菌株的主要流行株,对应MLST分型的CC92,菌株间具有较高同源性,提示存在鲍曼不动杆菌医院内传播的现象。

Objective To investigate the antibiotic resistance profile and molecular epidemiology of Acinetobacter baumannii in the neurosurgical intensive care unit（ICU）of a teaching hospital.Methods Overall 27 clinical isolates and 28 environmental strains of A.baumannii were isolated from the ICU at the same time period.The susceptibility of these strains to antimicrobial agents was determined by agar dilution method.Molecular genotyping was performed for all isolates by pulsed-field gel electrophoresis and multilocus sequence typing.The housekeeping genes gltA,gyrB,gdhB,recA,cpn60,gpi and rpoD were identified by PCR amplification.PCR results were sequenced and the alleles were compared with PubMLST databases.Results Clinical isolates were sensitive to colistin and tigecycline,but resistant to multiple antimicrobial agents,such as 25.9%to minocycline,51.9% to cefoperazone-sulbactam,59.3% to imipenem and more than 70% to other antibiotics tested.Environmental isolates were more sensitive than clinical isolates.Four major PFGE types were identified from the 27 clinical isolates and 5 distinct sequence types（STs）were defined by MLST.The 28 environmental isolates showed more diverse genetic types than clinical isolates.Conclusions The strains isolated from patients were genetically similar to the environmental strains.PFGE type A is the major clone,corresponding to CC92 by MLST typing.The homology among these A.baumannii strains suggests possible spread in the hospital.