中文摘要：

目的 了解鲍曼不动杆菌对碳青霉烯类、氨基糖苷类和氟喹诺酮类药物的耐药基因及其流行特性.方法 40株鲍曼不动杆菌分离自温州医科大学附属第一医院,菌株的鉴定及药物敏感情况通过Vitek 2 Compact微生物鉴定系统;琼脂稀释法及微量肉汤稀释法测定菌株对临床常用抗菌药物的敏感性,PCR扩增碳青霉烯类耐药基因、16S rRNA甲基化酶基因和喹诺酮类耐药基因;Southern杂交分析blaOXA-23和armA基因所在质粒或染色体的位置,并通过多位点序列分型（MLST）分析菌株的流行特点.结果 40株鲍曼不动杆菌,除对多黏菌素和替加环素全敏感外,对其他几种药物的耐药率均达100％,属于多重耐药菌.blaOXA-23、armA基因阳性率分别为90％和95％,所有菌株的gyrA和parC喹诺酮耐药决定区（QRDR）均发生突变,分别导致相应的83位和80位氨基酸替换.MLST结果显示,40株菌包含6种序列型（ST）,即ST191、ST381、ST373、ST426、ST208和ST207,其中主要为ST191（23株）和ST381（10株）.Southern杂交结果显示,ST191型鲍曼不动杆菌的blaOXA-23和armA基因均位于染色体上.结论 温州医科大学附属第一医院分离的鲍曼不动杆菌中主要的碳青霉烯酶和16SrRNA甲基化酶基因分别是blaOXA-23和armA,且两者可能均位于染色体上,垂直传播其耐药性;同时携带blaOXA-23和armA基因的ST191型多耐药鲍曼不动杆菌存在克隆播散现象.

英文摘要：

Objective To investigate the drug resistant genes against carbapenems,aminoglycosides and quinolones and the molecular epidemiology of clinical isolates of Acinetobacter baumannii.Methods Forty non-duplicate strains of Acinetobacter baumannii were collected from clinical specimens in First Affiliated Hospital of Wenzhou Medical University.The identification of strains was conducted by Vitek 2 Compact system.The susceptibilities to antimicrobials commonly used were determined by agar plate dilution method and broth microdilution method.The presence of class B metalloenzyme-encoding genes （blaIMP,blaVIM,blaNDM,blaSIM,blaGIM）,class D cabapenemase-encoding genes （blaOXA-23,blaOXA-48,blaOXA-58）,16S rRNA methylase genes （armA,rmtB） and quinolone resistance-determining regions （QRDR） in gyrA and parC were detected by polymerase chain reaction （PCR） and sequenced.Chromosomal or plasmid location of blaOXA-23 and armA genes were assessed by Southern blot.Multiple loci sequence classification （MLST） was performed to analyze the molecular epidemiology of these strains.Results All of the 40 isolates were multi-drug resistant Acinetobacterbaumannii （MDR-AB） and showed high level resistance to all of the tested antimicrobial agents excluding colistin and tigecycline.The positive rates of blaOXA-23 and armA were 90% and 95%,respectively.All of the 40 isolates carried QRDR mutations in gyrA and parC genes,leading to the Ser83→ Leu and the Ser80→ Leu amino-acid substitutions,respectively.Southern blot showed the chromosomal location of blaOXA-23 and armA genes.Six different ST （ST191,ST381,ST373,ST426,ST208 and ST207） were assigned for these isolates by MLST and the most dominant clones were ST191 （23/40） and ST381 （10/40）.Conclusions The predominant cabapenemase-encoding gene and 16S rRNA methylase gene of Acinetobacter baumannii isolates in First Affiliated Hospital of Wenzhou Medical University are blaOXA-23 and armA,respectively,which may be located on the chromosome and vertically t