鲍曼不动杆菌喹诺酮类耐药基因突变分析  

Analysis of resistant gene mutations of quinolone in Acinetobacter baumannii

作　　者：王敏[1] 覃章顺[1] 李先平[1] 杜世杰[2] 曹虹[1] 陈进伟[3] 

机构地区：[1]中南大学湘雅二医院检验科,湖南长沙410011 [2]中南大学湘雅医学院医学检验系2004级,湖南长沙410013 [3]中南大学湘雅二医院风湿免疫科,湖南长沙410011

出　　处：《中国病原生物学杂志》2010年第2期86-90,共5页Journal of Pathogen Biology

摘　　要：目的调查鲍曼不动杆菌对喹诺酮类药物的耐药情况，并对喹诺酮类耐药基因突变进行分析。方法对中南大学湘雅附二医院2002~2008年间鲍曼不动杆菌临床分离株的耐药情况进行统计。同时于2008年7～12月随机收集50株鲍曼不动杆菌，PCR扩增gyrA基因和parC基因，并对扩增产物进行限制性片段长度多态性分析（PCR—RFLP），选取部分PCR扩增产物进行测序和分析。结果鲍曼不动杆菌对喹诺酮类药物的耐药率呈逐年上升的趋势。50株鲍曼不动杆菌对环丙沙星耐药率为62％，对左氧氟沙星耐药率为46％。gyrA基因及parC基因扩增分别获得305bp和400bp的基因产物。PCR-RFLP结果显示，对gyrA基因，耐药株100％不能被HinfI酶切，敏感株53％能被HinfI酶切；对parC基因，耐药株29％能被HinfI酶切，敏感株有63％能被HinfI酶切。分析测序结果，耐药株中的gyrA基因和parC基因存在突变，未被酶切的敏感株也存在突变，使HinfI的识别序列GACTC变为GACTT，酶切位点GANTC消失。被酶切耐药株中发现parC基因新的突变点，第89碱基密码子GAA中的A突变成G，被酶切敏感株的parC基因出现多个位点的同义突变。结论鲍曼不动杆菌临床分离株对喹诺酮类药物耐药情况严重，呈逐年上升的趋势。鲍曼不动杆菌对喹诺酮类药物产生耐药与gyrA基因突变和parC基因突变有关。Objective To investigate the drug resistance of Acinetobacter baumannii to quinolones and analyze its resistance to gene mutations. Methods Statistical data on drug-resistant A. baumannii were collected from 2002 to 2008. At the same time, 50 A. baumannii strains were collected at the Second Xiangya Hospital of Central South University from July 2008 to December 2008. The gyrA gene and parC gene were amplified using PCR, and then analyzed by restriction fragment length polymorphism （PCR-RFLP）. Parts of PCR amplification products were sequenced and analyzed. Resuits The resistance rates of A. baumannii to quinolone tended to rise yearly. The resistance rates of 50 A. baumannii to ciprofloxacin and levofloxacin were 62% and 46%, respectively. The segment length of the gyrA gene amplification product was 305 bp and parC gene＇s was 400 bp. PCR RFLP results for Hinf I digestion of gyrA gene products indicated that 0 of resistant strains were digested and that 53% of susceptible strains were. Results for digestion of the parC gene indicated that 29% of resistant strains were digested and 63% of susceptible strains were. Sequencing results showed there were gene mutations of the gyrA gene and parC gene in the resistant strains and the same gene mutations also exis ted in some susceptible strains that could not be digested by Hinf I , which resulted in the recognition sequence GACTC being transformed into GACTT. Moreover, a new gene mutation was found in the parC gene of the digested resistant strains in the form of A → G in the 89th codon GAA. There were many sites of synonymous mutations in the parC gene of digested susceptible strains. Conclusion This study suggested that A. baumannii resistance to quinolones is serious and has worsened and that these developments may be related to gene mutations of gyrA and parC.

关 键 词：鲍曼不动杆菌 喹诺酮 GYRA PARC 基因突变 

分 类 号：R378.99[医药卫生—病原生物学]