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析：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大肠埃希菌产质粒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β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(KB法)进行药敏试验。结果233株大肠埃希菌中，头孢西丁

2、抑菌环直径≤17mm的有53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CMY2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、头孢西丁和含酶抑制剂的DR率明显高于非产酶株(P<0.05)，所有大肠埃希菌对亚胺培南和美罗培南均100%敏感。结论从老年患者中成功分离出产CMY2型质粒AmpC酶大肠埃希菌，产质粒AmpC酶菌株对β内酰胺类抗生素的耐药性明显高于非产酶株。【关键词

3、】质粒AmpC酶;大肠埃希菌;基因型;耐药性　　【Abstract】ObjectiveTounderstandthegenotypecharacteristicsanddrugresistance(DR)inEscherichiacoliproducingplasmidmediatedAmpCβlactamasesintheelderlypatientssoastoguidetherationaluseofantibioticsinclinical.Methods233strainsofE.coliisolate

4、dfromtheelderlypatientsinthe8hospitalsin2009ensionaltestandcertifiedtestpCandESBLs;conjugationexperimentplificationtestandscreeninganalysisedtoconfirmthegenotypeofplasmidmediatedAmpCβlactamases;Diskdiffusionsusceptibility(KBmethod)ong233Escherichiastrains，th

5、erem(22.7%)，7positivestrainsofthreedimensionaltestfromtheenzymicextractionofpC(1.7%);thedrugsensitivitydatasho，cefoxitinandcontainingenzymeinhibitorsicstrains(P<0.05).AllthestrainsofEscherichiacoliseropenemandimipenem.DRrateto12antibioticsofthesestrainspro

6、ducingenzyme(AmpCalone，ESBLsonly，bothplasmidAmpCandESBLs)ornothadstatisticallysignificantdifferences(P<0.05).Nonlactamaseproducingstrainsremainedatahighsensitivityrateto15kindsofantibiotics;DRrateoftheAmpCproducingstrainstothesecondandthirdgenerationcephal

7、osporins，aztreonamandcefoxitineandcarbapenems;ESBLsproducingstrainsalsoshoandotherantibiotics，buttheyostlysensitivetocarbapenem，enzymeinhibitorsandcefoxitin.BothAmpCandESBLsproducingstrainsincreasedDRratetootherantibioticsexceptmeropenemandimipenem(sensitive)s

8、ignificantly.ConclusionsTheresistanceofEscherichiacolitoβlactamantibioticsmainlyincludestheproductionofESBLsandAmpC，theenzymeproductionstrainscanbeselectedcarbapenemontheba