Abstract
李从荣,吕霞,罗少锋,黄俊.质粒介导的喹诺酮耐药基因qnr分子流行病学研究[J].Chinese journal of Epidemiology,2007,28(8):789-793
质粒介导的喹诺酮耐药基因qnr分子流行病学研究
Characterization of qnr gene for plasmid-mediated quionlone resistance
Received:November 01, 2006  Revised:August 10, 2007
DOI:
KeyWord: qnr基因  β-内酰胺酶基因  大肠埃希菌  阴沟肠杆菌  喹诺酮类  耐药
English Key Word: qnrgene  Broad spectrumβ-lactamaae gene  Escherichia coli  Enterobacter cloacac  Quinolone  Resistance
FundProject:
Author NameAffiliation
LI Cong-rong Department of Clinical Laboratory, Renmin Hospital, Wuhan University, Wuhan 430060, China 
LV Xia Department of Clinical Laboratory, Renmin Hospital, Wuhan University, Wuhan 430060, China 
LUO Shao-feng Department of Clinical Laboratory, Renmin Hospital, Wuhan University, Wuhan 430060, China 
HUANG Jun Department of Clinical Laboratory, Renmin Hospital, Wuhan University, Wuhan 430060, China 
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Abstract:
      目的 了解武汉大学人民医院分离的革兰阴性杆菌中qnr基因及其所携带的广谱β-内酰胺酶(ESBLs)基因的流行情况.方法 采用聚合酶链反应(PCR)方法对129株大肠埃希菌、29株肺炎克雷伯菌和10株阴沟肠杆菌进行qnr基因检测.对qnr阳性株,检测Ⅰ类整合酶基因及SHV-1、TEM-1、CTX-M、OXA-Ⅰ、OXA-Ⅱ、OXA-Ⅲ、DHA、EBC型ESBLs基因.KB纸片法检测对16种抗菌药物的体外抗菌活性,美国临床实验标准委员会表型筛选和确证试验检测产ESBLs株.质粒接合试验分析qnr基因的水平转移能力,ERIC-PCR进行DNA同源性分析.结果 6株菌株检出qnr基因(5株大肠埃希菌和1株阴沟肠杆菌),肺炎克雷伯菌中未检出;6株菌仅对亚胺培南全部敏感且对多种抗生素耐药,Ⅰ类整合酶基因扩增全为阳性,其中有2株大肠埃希菌对环丙沙星敏感,4株菌携带TEM-1型ESBLs基因、1株菌携带OXA-Ⅲ型ESBLs基因、2株菌携带EBC型AmpC酶;每株菌至少携带2种以上ESBLs基因.qnr基因介导的喹诺酮类耐药具有水平转移性,DNA同源性分析有2株指纹图谱一致.结论 武汉地区存在qnr基因的流行,qnr阳性株多重耐药严重,且携带多种ESBLs基因.
English Abstract:
      Objective To explore the distribution of qnr gene and broad spectrumβ-lactamase (ESBLs)gene in gram-negative bacteria which were isolated from our hospital patients.Methods qnr gene in nonrepetitive 129 isolates of Escherichia coli,10 isolates of Enterobacter cloacac and 29 isolates of K.pneunoniae were detected by polymerase chain reaction(PCR).For qnr gene positive strains,intⅠ, SHV-1,TEM-1,CTX-M,OXA-Ⅰ,OXA-Ⅱ,OXA-Ⅲ,DHA and EBC genes were examined.Plasmid conjugatable test was applied to examine whether qnr gene was located in conjugate plasmid and ERIC-PCR was carried out for DNA homologious analysis.ESBLs detection(according to phenotypic confirmatory test based on National Committee for Clinical Laboratory Standards criteria)and susceptibility test to 16 antibiotics were also performed.Results qnr gene was found in 6 clinical isolates including 5 strain of E.coli and one strain of E.cloacac,but qnr gene was undetectable in K.pneunoniae isolates.The 6 clinical isolates were suspectible to imipenem but resistance to some other drugs while only 2 isolates of E.coli were susceptible to quinolone.Among the 6 qnr gene-poaitive strains,all of them belonged toⅠtype integron-poaitive isolates,4 isolates of them were TEM-1 producing strains,with only one isolate was OXA-Ⅲgene producing strain,and 2 isolates of them were EBC producing strains.Most of them were with 2 ESBLs gene if not more.qnr gene was on transferable plasmids which could be disseminated by clone.Conclusion In Wuhan city,the prevalence of qnr was confirmed,qnr gene were found with some ESBLs gene in the same strains,and qnr gene in suspect strains.The transmission of qnr gene producing strains could be mediated by transferable plasmids or clone,forcing us to make intensive investigation and take effective control measures.
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