DHA1型质粒AMPC酶的研究

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1、上海交通大学硕士学位论文DHA-1型质粒AmpC酶的研究姓名：李卿申请学位级别：硕士专业：生物化学与分子生物学指导教师：蒋燕群20080501结果：临床资料分组比对后发现，不同病例组间的年龄，性别和基础疾病等风险因素方面的差异无统计学意义。前期应用三代头孢菌素和喹诺酮类在仅产AmpC酶和同时合并产ESBL的组间比较时有显著性差异。多数产DHA-1型酶的细菌呈多重耐药，并有一株菌对碳青霉烯类药物耐药。RAPD和质粒酶切图谱分析表明DHA-1的流行是由克隆传播和质粒播散共同作用造成的。8株DHA-1型质粒AmpC酶菌株接合成功。Southernblot实验证明DHA-1编码基因位于

2、质粒上，杂交片段为6-8KB。肺炎克雷伯菌与大肠埃希菌中扩增测序的AmpR与其起源的摩根摩根菌的AmpR蛋白进行比对，发现在229位（L-Q）和273（A-T）出现氨基酸序列的改变。结论：产DHA-1型质粒AmpC酶菌株感染者与CMY-2型感染者临床特征相似。仅产AmpC酶与同时合并产ESBL在前期应用抗生素方面有显著差。DHA-1型质粒AmpC酶的流行是由克隆传播和质粒播散共同作用造成的。对ampR基因与ampC基因克隆测序发现，相对于DHA-1型AmpC酶起源的摩根摩根菌而言，AmpR蛋白存在229位（L-Q）和273（A-T）的改变。关键词：AmpC酶,DHA-1,临床回

3、顾性研究,ampR,ampDTHESTUDYOFDHA-1-TYPEPLASMID-MEDIATEDAmpC5β-LACTAMASEABSTRACTObjective:TheaimofthisprojectistostudyourclinicalisolatesthatproduceDHA-1-typeplasmid-mediatedAmpCβ-lactamaseintermsofantibioticssusceptibility,prevalenceandinpatientsclinicalfeatures.Theresultswouldprovidevaluableinfo

4、rmationforresistantspectrum,prevalencecontrolofantibioticresistance,andclinicalsignificancecausedbytheseDHA-1andCMY-2pathogens.Theregµlatorygenesarealsoinvestigatedforbetterunderstandingofregµlationmechanismsanditscorrelationwithinductionphenomenon.Methods:1.Collectingtheclinicaldataofinpati

5、entsinfectedbyDHA-1andCMY-2producingE.coliandK.pneumoniae,andcomparingtheriskfactorsofdifferentgroups.2.MICtest,polymerasechainreaction(PCR)amplificationandsequencingtodeterminetheantibioticsusceptibility,plasmidtransfer,theDHA-1geneandotherESBLgenes.3.RandomamplifiedpolymorphicDNA(RAPD)wasu

6、sedtoinvestigatetheoriginofdifferentDHA-1isolates.4.ConjugationandplasmidprofilesfurtherdescribethedisseminationofplasmidcarryingDHA-1amongwards.5.6SouthernblottingwastakentolocatetheDHA-1geneandthebandsizewhereitlocates.6.PCRamplificationandsequencingofthemainregµlatorygenesblaampRandblaamp

7、D,thenclonebothblaampRandblaampCtoplasmidpUC19andtesttherecombinant’sMIC.Results:Tofurtherdescribetheclinicalfeaturesofthe32DHA-1and10CMY-2infectiousinpatientsfromJanuary2003toJuly2005,theywereclassifiedtotwocomparinggroups:onlyAmpCandAmpCwithESBLs