临床分离枸橼酸杆菌qnr基因型检测  

Detection of qnr genotypes in clinical isolated citrobacter strains

作　　者：钟涛[1] 许伟[1] 徐元宏[2] 

机构地区：[1]安徽医科大学第一附属医院输血科,合肥230022 [2]安徽医科大学第一附属医院检验科,合肥230022

出　　处：《安徽医科大学学报》2010年第2期261-265,共5页Acta Universitatis Medicinalis Anhui

基　　金：安徽省十五攻关二期科研课题(编号:040130583)

摘　　要：目的探讨临床分离的多重耐药枸橼酸杆菌qnr基因的存在情况。方法聚合酶链反应(PCR)法扩增各组qnr基因,对扩增产物进行基因测序和同源性比较,质粒结合试验,琼脂稀释法测定17种抗菌药物的最低抑菌浓度(MIC)。结果52株枸橼酸杆菌中有22株细菌检出qnr基因,其中5株菌携带qnrA基因,11株菌携带qnrB2基因,1株菌携带qnrB4基因。挑选2株qnrA基因测序与阴沟肠杆菌qnrA基因(GenBank登录号:DQ983226)的同源性为100%;3株qnrB2基因测序与弗劳地枸橼酸杆菌qnrB2基因(GenBank登录号:AB281054)的同源性均为97%,17个碱基突变,其中2个氨基酸发生改变(GenBank注册号:EF526508);1株qnrB4基因(GenBank注册号:EF543140)测序与大肠埃希菌qnrB4基因(GenBank登录号:DQ303921)的同源性为100%。只有1株细菌qnrA基因结合试验成功。52株枸橼酸杆菌对氟喹诺酮类药物的耐药率达到70%以上。结论枸橼酸杆菌临床分离株中qnr基因检出率较高,应引起高度重视。Objective To investigate qnr genotypes of multiresistant Citrobacter strains isolated from clinical specimens.Methods The qnr genes of corresponding group were amplified by polymerase chain reaction （PCR）,the sequence and homology of PCR products were analyzed,plasmid conjugation test,standard agar dilution method was used to determine the minimal inhibitory concentration （MIC） of seventeen antibacterials.Results The qnr genes were identified in 22 of 52 Citrobacter strains,which consisted of 5 strains had qnrA gene and 11 strains had qnrB2 gene,1 strain had qnrB4 gene.Sequence analysis revealed that 2 of qnrA gene was sequenced,DNA sequence of they revealed 100% identities of the qnrA amino acid sequence of Enterobacter cloacae （GenBank No.DQ983226）,3 of qnrB2 gene was sequenced,DNA sequence of they revealed 97% identities of qnrB2 amino acid sequence of Citrobacter freundii （GenBank No.AB281054）,seventeen points mutation leads to two amino acid change （GenBank accession No.EF526508）;1 qnrB4 gene （GenBank accession No.EF543140） was sequenced,DNA sequence revealed 100% identities of the qnrB4 amino acid sequence of Escherichia coli （GenBank No.DQ303921）.Only one Citrobacter strain plasmid transfer of qnrA gene was achieved.The rates of 52 Citrobacter strains resistance to Fluoroquinolones were more than 70%.Conclusion The positive rate of the qnr genes in Citrobacter strains isolated is higher,which should be highly concerned.

关 键 词：喹诺酮类 

分 类 号：R378.2[医药卫生—病原生物学] R916.4[医药卫生—基础医学]