临床医学毕业论文老年患者大肠埃希菌产质粒ampc酶基因型特点及耐药性分析

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1、老年患者大肠埃希菌产质粒AmpC酶基因型特点及耐药性分姓名：2014年6月25日作者：张淑芳吴多荣张应爱黄会韩小胜【摘要】目的了解临床分离老年患者人肠埃希菌产质粒AmpC酶的基因型及其耐药(DR)性特点，为临床合理选用抗生素提供依据。方法收集2009年度老年患者临床不重复分离大肠埃希菌233株，用三维试验和确证试验分别进行羟氨苄青霉素(AmpC)酶和超广谱P内酰胺酶(ESBLs)检测，用接合试验证实酶基因型的转移，通过PCR检测及序列分析进行质粒AmpC酶基因型确定，采用药敏纸片扩散法(KB法)进行药敏试验。结果233株人肠埃希菌屮，头孢西丁抑菌环直径S17mm的有5

2、3株，占22.7%,酶提取物三维试验检测7株阳性，4株(1.7%)PCR扩增出CMY2型质粒AmpC酶，有1株接合试验阳性;ESBLs阳性占68.7%(160/233)。药敏结果显示产质粒AmpC酶大肠埃希菌对二、三代头孢菌素、氨曲南、尖孢西丁和含酶抑制剂的DR率明显高于非产酶株(P0.05)，所有大肠埃希菌对亚胺培南和美罗培南均100%敏感。结论从老年患者屮成功分离出产CMY2型质粒AmpC酶大肠埃希菌，产质粒AmpC酶菌株对(3内酰胺类抗生素的耐药性明显高于非产酶株。【关键词】质粒AmpC酶;大肠埃希菌;基因型;耐药性[Abstract]ObjectiveToun

3、derstandthegenotypecharacteristicsanddrugresistance(DR)inEscherichiacoliproducingplasmidmediatedAmpCPlactamasesintheelderlypatientssoastoguidetherationaluseofantibioticsinclinical.Methods233strainsofE.coliisolatedfromtheelderlypatientsinthe8hospitalsin2009werecollected.Threedimensionalt

4、estandcertifiedtestwereusedtodetectAmpCandESBLs;conjugationexperimentwereusedtoverifythetransitivityofgenotype.PCRamplificationtestandscreeninganalysiswereperformedtoconfirmthegenotypeofplasmidmediatedAmpCPlactamases;Diskdiffusionsusceptibility(KBmethod)wasadoptedtodetectdrugsensitivete

5、st.ResultsAmong233Escherichiastrains，therewere53EscherichiastrainsofwhichCefoxitininhibitionzonewasequaltoorbelow17mm(22.7%)，7positivestrainsofthreedimensionaltestfromtheenzymicextractionofwhichtherewere4strainsproducingCMY2typeAmpC(1.7%);thedrugsensitivitydatashowedthattheresistancetot

6、hesecondandthirdgenerationcephalosporins,aztreonam,cefoxitinandcontainingenzymeinhibitorsweresignificantlyhigherthanthoseofthenoenzymicstrains(P0.05).AllthestrainsofEscherichiacolisweresensitivetomeropenemandimipenem.DRrateto12antibioticsofthesestrainsproducingenzyme(AmpCalone，ESBLsonly

7、，bothplasmidAmpCandESBLs)ornothadstatisticallysignificantdifferences(P0.05).Nonlactamaseproducingstrainsremainedatahighsensitivityrateto15kindsofantibiotics;DRrateoftheAmpCproducingstrainstothesecondandthirdgenerationcephalosporins，aztreonamandcefoxitinwasupto100%.However,these