耐碳青霉烯类抗生素大肠埃希菌的耐药基因检测及传播机制探讨  

Resistance gene test and molecular typing characteristics of carbapenem-resistant antibiotic Escherichia coli

作　　者：俞凤[1] 胡龙华[1] 蒋沁炆 钟桥石[1] 陈艳慧[1] 方雪瑶 YU Feng;HU Longhua;JIANG Qinwen;ZHONG Qiaoshi;CHEN Yanhui;FANG Xueyao(The Second Affiliated Hospital of Nanchang University,Jiangsu Key Laboratory of Laboratory Medicine,Nanchang 330006,China)

机构地区：[1]南昌大学第二附属医院/江西省医学检验重点实验室,南昌330006

出　　处：《山东医药》2018年第47期36-39,共4页Shandong Medical Journal

基　　金：江西省科技厅支持项目(20171BAB215079)

摘　　要：目的检测耐碳青霉烯类抗生素大肠埃希菌的耐药基因,并探讨其传播机制。方法临床分离的耐碳青霉烯类抗生素大肠埃希菌3株,分别编码为DC10、DC44、DC52。用PCR法扩增筛查DC10、DC44、DC52的耐药基因,对扩增产物测序确定基因型别;通过接合实验得到DC10、DC44、DC52与耐叠氮钠的大肠埃希菌J53的接合子,对接合子进行菌种鉴定、药敏试验、耐药基因检测及测序;采用多位点序列分析(MLST)确定DC10、DC44、DC52的基因序列型(ST型),并利用e BURST软件进行亲缘性分析。结果 DC10、DC44、DC52中bla NDM基因均阳性,其它碳青霉烯类耐药基因、喹诺酮类耐药基因均阴性。经测序确认DC10、DC52均携带bla NDM-1基因,其中DC52同时携带bla TEM-1基因; DC44携带bla NDM-3基因,同时携带bla TEM-1基因和bla CTX-M-15基因。DC10、DC44、DC52均与J53接合成功,接合子为大肠埃希菌。接合子除对替加环素、阿米卡星敏感外,对β-内酰胺酶类和碳青霉烯类抗生素均耐药,接合子均含有与DC10、DC44、DC52相同的碳青霉烯酶基因。DC10的MLST分型为ST744、DC44为ST7219、DC52为ST167。ST744和ST167同属于CC10克隆群,ST7219属于CC131克隆群。结论耐碳青霉烯类抗生素大肠埃希菌的耐药基因为bla NDM基因,耐药基因bla NDM均能通过质粒水平传播。Objective To detect the resistance genes of carbapenem-resistant antibiotic Escherichia coli and to discuss its transmission mechanism.Methods Three clinically isolated carbapenem-resistant antibiotic Escherichia coli strains were encoded as DC10,DC44,and DC52,respectively.We screened out the resistance genes of them by PCR,the genotypes of amplified products were determined;the plasmid characteristics were analyzed by conjugation experiment;we did the species identification and drug sensitivity test,and meanwhile,the resistance genes were detected and sequenced;multiple locus sequence analysis(MLST)was used to determine the allele number and gene sequence type(ST type),and the affinity was analyzed by eBURST software.Results The blaNDM genes were positive in DC10,DC44 and DC52,and other carbapenem resistance genes and quinolone resistance genes were negative.It was confirmed by sequencing that both DC10 and DC52 carried the blaNDM-1 gene.DC44 carried the blaNDM-3 gene and carried the blaTEM-1 gene and the blaCTX-M-15 gene.DC10,DC44,and DC52 were all successfully joined to J53,and the conjugation was Escherichia coli.In addition to being sensitive to tigecycline and amikacin,the conjugation were resistant to bothβ-lactamase and carbapenem.The DC10,DC44,and DC52 were successfully joined to J53,and the conjugation contained the same carbapenemase gene as DC10,DC44,and DC52.DC10,DC44,and DC52 were three sequential types(ST):DC10 was ST744,DC44 was ST7219,and DC52 was ST167.ST744 and ST167 belonged to the CC10 clonal group,and ST7219 belonged to the CC131 clonal group.Conclusion The resistance gene of the carbapenem-resistant antibiotic Escherichia coli is blaNDM gene,and the drug resistance gene blaNDM can be transmitted horizontally through the plasmid.

关 键 词：耐药基因 大肠埃希菌 碳青霉烯酶 碳青霉烯类抗生素 

分 类 号：R446.5[医药卫生—诊断学]