铜绿假单胞菌中质粒介导喹诺酮类耐药基因的研究

目的了解广州地区质粒介导喹诺酮类耐药（PMQR）基因在铜绿假单胞菌中的流行状况并分析其与耐药之间的关系。方法收集2005-2007年临床分离到的212株铜绿假单胞菌,采用K-B纸片扩散法进行药敏试验,通过PCR检测质粒介导喹诺酮类耐药基因qnrA、qnrB、qnrS、qnrC、qnrD、aac（6’）-Ib-cr和qepA,并对阳性扩增产物进行DNA测序分析。结果 212株铜绿假单胞菌对喹诺酮类药物环丙沙星和左氧氟沙星的耐药率分别为10.8%（23/212）和19.3%（41/212）。qnrB、qnrS和aac（6’）-Ib-cr的阳性率分别为0.9%（2/212）、0.5%（1/212）和0.9%（2/212）,qnrA、qnrC、qnrD、qepA未检出。4株PMQR基因阳性菌株中,仅1株对左氧氟沙星表现为耐药,其余对环丙沙星和左氧氟沙星均表现为敏感。结论 2005-2007年间广州地区铜绿假单胞菌耐药现象严重,该地区铜绿假单胞菌中已携带有PMQR基因,且敏感菌株中也有该类基因存在。

Plasmid-mediated quinolone resistance genes in Pseudomonas aeruginosa

Objective To investigate the prevalence of plasmid-mediated quinolone resistance （PMQR） genes in Pseudomonas aeruginosa isolated from clinical in Guangzhou and analysis the correlation with drug resistance. Methods The antimierobial susceptibility test was performed by disc diffusion method in all 212 Pseudomonas aeruginosa. The Plasmidmediated quinolone resistance genes qnrA, qnrB, qnrS, qnrC, qnrD, aac（6＇ ）-Ib-cr and qepA were detected by PCR, the positive products were purified and sequenced. Results In the 212 Pseudomonas aeruginosa strains, the average resistance rates of Ciprofloxaein and Levofloxacin were 10.8% （23/212） and 19.3% （41/212）. The positive rates of qnrB, qnrS, aac（6＇）-Ib-cr were 0.9% （2/212）, 0.5% （1/212）, and 0.9% （2/212） respectively. No qnrA, qnrC, qnrD, and qepA were detected. In the 4 PMQR gene positive strains, only 1 showed resistance to Levofloxacin, others were susceptible to both Ciprofloxacin and Levofloxacin. Conclusions The antimicrobial resistance level of Pseudomonas aeruginosa is high in Guangzhou during 2005-2007. The PMQR genes were discovered in Pseudomonas aeruginosa in Guangzhou and these genes also existing in quinolone susceptible strains.