临床分离产ampcβ┐内酰胺酶阴沟肠杆菌的耐药性分析

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1、临床分离产AmpCβ┐内酰胺酶阴沟肠杆菌的耐药性分析作者：凌保东余娴谢勇恩雷军【摘要】　　目的研究我院临床分离阴沟肠杆菌的产AmpC酶耐药情况及ampC基因型。方法收集临床分离的耐药阴沟肠杆菌15株;检测产AmpC酶和超广谱β-内酰胺酶（ESBLs）的菌株;测定MIC值;PCR扩增检测ampC基因及序列测定。结果15株菌中8株菌（53.3%）产AmpC酶，3株菌（20.0%）产ESBLs。产AmpC酶的菌株除对亚胺培南全敏感外，对其它抗菌药不同程度耐药。ampC基因与阴沟肠杆菌ECLC074的ampC基因高度同源。结论产AmpC酶是阴沟肠杆菌对β-内酰胺类抗

2、生素耐药的主要机制之一。阴沟肠杆菌ECLC074ampC基因是我院主要的阴沟肠杆菌ampC基因型。产AmpC酶的阴沟肠杆菌常呈多重耐药，亚胺培南是治疗此类菌所致感染的最有效药物。【关键词】阴沟肠杆菌头孢菌素酶ampC基因　　Avarietyofβ-lactamaseshavebeenclassifiedintoclassesA，B，C，andDaccordingtotheiraminoacidhomologies［1］.AmpCβ-lactamases，mostlyconferringresistancetomanyβ-lactamantibiotics（c

3、ephamycinsandbroad-spectrum9cephalosporins），areincludedinclassCβ-lactamases.ChromosomallyencodedAmpCβ-lacta-masesarepresentinEnterobacterspp.，Shigellaspp.，Serratiamarcescens，Citrobacterfreundii，Morganellamorganii，Providenciaspp.，Pseudomonasaeruginosa，andEscherichiacoli［2］.Enterobac

4、tercloacaearebecom-ingincreasinglyimportantasnosocomialpathogens［3］.InviewofthespreadingriskofAmpCresistancedeter-minantsamongenterobacterialisolates，itisnecessarytoelucidatetheAmpCresistancemechanism.ThisstudywasconductedtodeterminetheprevalenceandgenotypesofAmpCβ-lactamasesamongc

5、linicalisolatesofEnterobactercloacae.MaterialsandmethodsClinicalstrains15randomlychosenpiperacillin-resistantE.cloacaewereisolatedfromFebruary2003toJanuary2004intheAffiliatedHospitalofNorthSichuanMedicalCollege.DetectingforproductionofESBLsandAmpCβ-lactamases:Crudeβ-lactamaseprepar

6、ationswereobtainedbysonicationandthequalitationdetectionofβ-lactamasewasperformedbynitrocefin.TheproductionofESBLswastestedaccordingtoNCCLSScreeningandConfirmatorytest.AmpCβ-lactamasewasexaminedbythreedimensiontest［4］.9Antibacterialsusceptibility:MICsofantibacterialstoAmpCβ-lactama

7、seproducersweredeterminedbytwo-foldagardilutionmethod.E.coliATCC25922andK.pneumoniaeATCC700603wereusedasreferencestrains.PCRofampCgenes，thegenomicDNAofAmpCβ-lactamaseproducers，waspreparedwiththegenomicDNAminipreparationkit（Sangon，Shanghai，China）andusedasthetemplateDNAinPCRanalysis.

8、ThePCRprimerswereAmpCF（5′-