南京地区鲍曼不动杆菌喹诺酮类药物耐药基因突变的研究  

Survey on gene mutations of quinolone-resistant Acinetobacter baumannii in Nanjing region of China

作　　者：赵旺胜[1] 江淑芳[2] 顾兵[1] 吴姗姗[1] 刘根焰[1] 张巧娣[1] 吴海玮[3] 

机构地区：[1]南京医科大学第一附属医院检验中心,南京210029 [2]中国人民解放军第81医院,南京210006 [3]南京医科大学病原生物学系,南京210029

出　　处：《临床检验杂志》2007年第2期90-92,共3页Chinese Journal of Clinical Laboratory Science

摘　　要：目的调查南京地区鲍曼不动杆菌对喹诺酮类药物的耐药情况,并研究其耐药机制。方法在南京地区的医院随机收集了73株鲍曼不动杆菌,历时9个月。定量肉汤稀释法测定菌株对左氧氟沙星、环丙沙星和加替沙星3种喹诺酮类药物的MIC,PCR扩增gyrA基因和parC基因并进行酶切分析,选取部分PCR扩增产物进行测序。结果鲍曼不动杆菌对左氧氟沙星耐药率为39.7%(29/73);对环丙沙星耐药率为76.7%(56/73);对加替沙星耐药率为32.9%(24/73)。对3种喹诺酮类药物均耐药的有16株,占21.9%。PCR-RFLP显示,对gyrA基因,耐药株有80.4%(45/56)不能被HinfⅠ酶切,敏感株100%(17/17)被HinfⅠ酶切;对parC基因,耐药株73.2%(41/56)不能被HinfⅠ酶切,敏感株有88.2%(15/17)被HinfⅠ酶切。测序结果:耐药株中的gyrA和parC基因存在突变,敏感株中则不存在突变,并在耐药株中发现gyrA和parC基因新的点突变,Genbank号分别为DQ270238和DQ270239。结论南京地区鲍曼不动杆菌对喹诺酮类药物耐药情况严重,其耐药与gyrA和parC基因突变有关。Objective To investigate the current status of A. baumannii resistance to quinolones in Nanjing region of China and examine the related mechanisms. Methods During 9 months,73 isolates of A. baumannii were collected randomly from hospitals in Nanjing region. MICs of levofloxacin,ciprofloxacin and gatifloxacin were determined using broth dilution method. Genes gyrA and parC were amplified by polymerase chain reaction （PCR） ,and all PCR products were digested with Hinf Ⅰ and some of them were sequenced. ResuIts Of the 73 isolates ,39.7% （ 29/73 ） were resistant to levofloxacin, 76.7% （ 56/73 ） were resistant to ciprofloxacin, 32.9% （ 24/73 ） were resistant to gatifloxacin,and 16 strains （21.9%） of the collected strains were resistant to all the three quinolones. PCR-RFLP revealed that 80.4% （45/56）of the amplified gyrA genes from the quinolones resistant strain could not be digested by Hinf Ⅰ, while 100% （17/17） from the sensitive strains could be digested. 73.2% （41/56） of the amplified parC genes from the resistant strain could not be digested by Hinf Ⅰ ,but 88.2% （15/17 ） from the sensitive strains couid be digested. DNA sequencing indicated that there were point mutations in both gyrA and parC genes of quinolones resistant strains but no mutation in sensitive strains. We,with The Genbank number of the new point mutations in gyrA and parC genes of resistant strains reported by us are DQ270238 and DQ270239,respectively. Conclusions The current status of resistance to quinolones among A. baumannii strains in Nanjing region of China is serious, and the resistance is related to the point mutations within gyrA and parC genes.

关 键 词：鲍曼不动杆菌 喹诺酮 耐药机制 

分 类 号：R446.5[医药卫生—诊断学]