摘要
目的探讨铜绿假单胞菌临床分离株中是否存在质粒介导喹诺酮类耐药(PMQR)机制。方法收集2010年1-12月中山大学附属第三医院临床分离的无重复铜绿假单胞菌256株,采用微量肉汤稀释法测定环丙沙星最低抑菌浓度(MIC),应用PCR方法扩增PMQR基因qnrA、qnrB、qnrC、qnrD、qnrS、aac(6′)-Ib-cr、qepA,并对PCR阳性产物进行测序分析以确定基因亚型。结果 256株铜绿假单胞菌对环丙沙星的耐药株和敏感株分别为65株和180株,MIC50和MIC90分别为0.5μg/ml、16μg/ml;全部菌株中只有1株检测到qnrA基因,其PCR阳性产物经测序证实为qnrA1亚型,环丙沙星对该菌株的MIC为2μg/ml;未检测到qnrB、qnrC、qnrD、qnrS、aac(6′)-Ib-cr和qepA基因。结论国内首次从铜绿假单胞菌中发现qnrA1基因,该耐药基因介导细菌对环丙沙星低水平耐药,PMQR尚未成为铜绿假单胞菌对喹诺酮类耐药的主要机制之一。
OBJECTIVE To explore the mechanisms of plasmid-mediated quinolones resistance （PMQR） in Pseudo-rnonas aeruginosa （P. aeruginosa） clinical isolates. METHODS A total of 256 strains of non-repetitive P. aerugi-nosa isolated from the Third Affiliated Hospital of Sun Yat-sen University between Jan 2010 and Dec 2010 were collected. Minimal inhibitory concentration （MIC） of ciprofloxacin to P. aeruginosa was determined by broth microdilution method. And PMQR gene qnrA, qnrB, qnrC, qnrD, qnrS, aac（6＇）-Ib-cr, and qepA of P. aerugi-nosa clinical isolates were amplified by PCR. Then the PCR positive products were sequenced to identify their genotypes. RESULTS Of 256 strains of P. aeruginosa investigated, there were 65 strains of ciprofloxaein-resistant P. aeruginosa and 180 strains of ciprofloxacin-sensitive P. aeruginosa. The MIC50 and MIC90 were 0.5μg/ml and 16μg/ml, respectively. Among all clinical isolates, qnrAl gene was detected in 1 strain, and the MIC of ciprofloxacin of the strain was 2μg/ml. The PMQR genes including qnrB, qnrC, qnrD, qnrS, aac （6＇）-Ib-cr and qepA were not detected in any of the strains. CONCLUSION This is the first report in China that qnrAl gene is related to low level resistance to ciprofloxacin in P. aeruginosa clinical isolates. Up to the present day, PMQR has not yet become one of the principal mechanisms of resistance to quinolones in P. aeruginosa.
出处
《中华医院感染学杂志》
CAS
CSCD
北大核心
2013年第11期2524-2526,共3页
Chinese Journal of Nosocomiology
关键词
铜绿假单胞菌
质粒
喹诺酮类
耐药机制
基因
Pseudomonasaeruginosa
Plasmid
Quinolones
Resistance mechanism
Gene
