产质粒介导AmpC酶大肠埃希菌中整合子的检测  

Detection of integrons in plasmid-mediated AmpC β-lactamase-producing Escherichia coli

作　　者：丁娟娟[1] 陈卓昌[1] 

机构地区：[1]河南省人民医院呼吸科,郑州450003

出　　处：《临床医学》2011年第10期1-4,共4页Clinical Medicine

摘　　要：目的探讨大肠埃希菌产质粒介导AmpC酶对抗生素的耐药情况,以及整合子的存在状况,为临床合理用药提供依据。方法收集河南省人民医院临床分离大肠埃希菌,对头孢西丁耐药株以酶提取物改良三维试验筛选高产AmpC酶株;多重PCR和DNA测序分析质粒AmpC基因型;用PCR-限制片段长度多态性(RFLP)初筛整合子并分型,PCR扩增整合子的可变区并测序。结果 126株大肠埃希菌中,检出产质粒介导AmpC酶14株(26.9%),对筛出的耐药菌株采用琼脂对倍稀释法检测耐药性;多重PCR扩增分析示:其基因型均为CMY-2型。8株耐药菌株检出1类整合子,序列分析显示存在aadA4、aadA5、aadB、cm lA、cm lA1、和dfr17基因盒,它们分别介导对氨基糖苷类抗生素、氯霉素和甲氧苄明的耐药。结论治疗产质粒介导AmpC酶的细菌感染时,应以第四代头孢菌素和碳青霉烯类抗生素为首选。我院大肠埃希菌临床分离株产质粒介导AmpC率较高,其基因型为CMY-2型,而相关耐药基因盒并未位于整合子上。Objective To investigate the resistance of plasmid-mediated AmpC β-lactamase-producing Escherichia coli and the molecular mechanism of integrons participated multi-resistance in these strains.Methods Three-dimensional extract test was used to screen AmpC β-lactamase.The genes of plasmid-mediated AmpC and integrons were analyzed using PCR and verified DNA sequencing.Results Among the 126 strains,14 isolates were detected producing plasmid-mediated AmpC,and CMY-2 was the unique genotype.Class 1 integrons were detected in 8 of 14 isolates by PCR using primers targeted to conserved regions of class 1,2 and 3 integrase genes.DNA sequencing analysis revealed amplicons contained aadA4,aadA5,aadB,cmlA,cmlA1,and dfr17 gene cassettes that confer resistance to the aminoglycoside,chloramphenicol and trimethoprim respectively.Conclusion It suggested that the fourth generation cephalosporins and caropenems should be chosen in clinical empirical medication for plasmid mediated AmpC β-lactamases-producing E.coli isolates.In our hospital,the genetype coding plasmid-mediated AmpC in the isolates of Escherichia coli is CMY-2.But it was not located on integrons.

关 键 词：大肠埃希菌 质粒介导AMPC酶 多重PCR 整合子 

分 类 号：R440[医药卫生—诊断学]