摘要
目的了解多重耐药肺炎克雷伯菌克隆播散状况及质粒介导耐药性的传播特性。方法连续收集2009年12月至2012年2月分离自浙江大学医学院附属第一医院的53株非重复多重耐药肺炎克雷伯菌。采用K-B纸片法进行药敏试验,脉冲场凝胶电泳(PFGE)进行临床菌株克隆分型,滤膜接合法进行质粒接合试验。采用SI酶切结合PFGE的方法判读质粒的相对分子质量,并采用PCR扩增筛选接合菌株的常见耐药基因。结果53株肺炎克雷伯菌对青霉素类药物的耐药率为100%;对哌拉西彬/他唑巴坦、头孢哌酮/舒巴坦等混合制剂的敏感率低于15%;对头孢菌素的耐药率也很高,在86%以上;对喹诺酮类、磺胺类和四环素类药物的耐药率为60%~70%;且50%左右的菌株对碳青霉烯类药物不敏感。PFGE分型显示这些菌株克隆传播趋势不明显。耐药菌株常携带可接合性耐药质粒,质粒的相对分子质量为34000~355000bp,编码对青霉素类、头孢菌素类、碳青霉烯类、氨基糖苷类等药物耐药的多种基因,包括CTX—M型、TEM型、KPC型β-内酰胺酶基因,以及质粒介导喹诺酮耐药基因qnr等。结论临床分离的肺炎克雷伯菌多重耐药形势严峻,耐药性的快速传播已不是同源克隆细菌的简单播散,而是可接合性质粒的耐药基因快速水平转移。
Objective To investigate the spreading characteristics of plasmid-mediated resistance and the clones dissemination in multidrug resistant Klebsiella pneumoniae. Methods A total of 53 strains of muhidrug resistant Klebsiella pneumoniae were successively collected from the First Affiliated Hospital, Zhejiang University School of Medicine during December 2009 and February 2012. Antimicrobial agents susceptibility was determined by Kirby-Bauer (K-B) method, and pulsed field gel electrophoresis (PFGE) was used to investigate the clonality of clinical isolates. Filter mating method was used for plasmid conjugation, and the relative molecular mass of the plasmid was determined using Sl-PFGE assay. PCR amplification and sequencing were used to screen common antimicrobial resistance genes. Results Fifty- three clinical isolated Klebsiella pneumoniae strains were all resistant to penicillins, and their sensitive rates to piperacillin/tazobaetam, eefoperazone/sulbactam were below 15%. More than 86% strains were resistant to eephalosporins, and 60%-70% strains were resistant to quinolones, sulfonamides and tetracyclines. About 50% strains were resistant or intermediate sensitive to carbapenems. PFGE results did not support the evidence of clone dissemination. Resistant isolates harbored conjugant plasmid with 34 000-355 000 bp size, which encoded penicillins, cephalosporins, earbapenems or aminoglycoside resistant determinants, including CTX-M, TEM, KPC type β-lactamase genes and plasmid-mediated quinolone resistance gene qnr.Conclusions Multidrug resistance is prevalent in clinical Klebsiella pneumoniae isolates. Rapid prevalenceof resistance is mainly determined by conjugant plasmid horizontal transfer rather than simple clone dissemination.
出处
《中华临床感染病杂志》
CAS
2014年第4期295-300,共6页
Chinese Journal of Clinical Infectious Diseases
基金
国家自然科学基金青年科学基金项目(81301460)
关键词
克雷伯菌
肺炎
抗药性
多药
质粒
接合
遗传
Klebsiella pneumoniae
Drug resistance,multiple
Plasmid
Conjugation, genetic