携带blaCTX-M-55基因的大肠埃希菌氨基糖苷类耐药相关元件分析  

Investigation of aminoglycoside resistant determinants in Escherichia coli carrying blaCTX-M-55

作　　者：谭麟[1] 马红映[2] 汪丽[3] 吕丹[2] 郑琳[3] 邓在春[2] 

机构地区：[1]宁波大学医学院附属医院普外科,浙江宁波315020 [2]宁波大学医学院附属医院呼吸科,浙江宁波315020 [3]宁波大学医学院附属医院细菌室,浙江宁波315020

出　　处：《中华医院感染学杂志》2017年第11期2405-2408,共4页Chinese Journal of Nosocomiology

基　　金：宁波市自然科学基金资助项目(2016A610132)

摘　　要：目的调查携带blaCTX-M-55基因的大肠埃希菌中氨基糖苷类耐药相关元件的携带状况,以及了解本组菌株间的亲缘关系。方法收集2015年1-12月宁波大学医学院附属医院住院患者痰液标本中分离30株携带blaCTX-M-55基因的大肠埃希菌,用K-B法测定9种抗菌药物的敏感性,采用聚合酶链反应(PCR)及序列分析的方法分析7种氨基糖苷类修饰酶基因,2种16SrRNA甲基化酶基因,7种可移动遗传元件遗传标记,阳性耐药基因测序后直接作BLAST比对,耐药基因检测结果作样本聚类分析(UPGMA法)。结果 30株携带blaCTXM-55基因的大肠埃希菌对头孢类、氨基糖苷类、喹诺酮类抗菌药物均耐药,但对碳青霉烯类抗菌药物均为敏感;30株菌均检出氨基糖苷类修饰酶基因和可移动遗传元件遗传标记,另有5株检出16SrRNA甲基化酶基因,30株菌共检出5种氨基糖苷类修饰酶基因、1种16SrRNA甲基化酶基因、7种可移动遗传元件遗传标记,且阳性率较高;样本聚类分析显示,该组菌株有明显的聚集性,有6个克隆传播。结论本组30株携带blaCTX-M-55基因的大肠埃希菌同时携带了氨基糖苷类修饰酶基因、16SrRNA甲基化酶基因和可移动遗传元件遗传标记,是对头孢类和氨基糖苷类产生耐药的重要原因;本组菌检出的6个克隆高度疑似医院感染,同一克隆菌株携带相同基因。OBJECTIVE To investigate the distribution of aminoglycoside resistant determinants in a group of Escherichia coli carrying blaCTX-M-55 （CTX-ECO）,so as to investigate phylogenetics of this group of CTX-ECO.METHODS From Jan.2015 to Dec.2015,30 strains of CTX-ECO isolated from sputum were collected from the Affiliated Hospital of School of Medicine of Ningbo University.Drug sensitivity to 9 kinds of antimicrobial agents were performed by K-B method,and then 7 kinds of aminoglycosides modifying enzyme genes,2 kinds of 16S rRNA methylase gene,and 7 kinds of genetic markers of mobile genetic elements were analyzed by PCR.Positive resistant genes were performed BLAST algorithm after DNA sequencing.Finally,resistant genes were used as molecular markers to perform sample cluster analysis （UPGMA）.RESULTS Totally 30 strains of CTX-ECO all carried blaCTX-M-55,and were resistant to cephalosporins,aminoglycosides and quinolones,but susceptible to carbopenams.Aminoglycosides modifying enzyme genes and genetic markers of mobile genetic elements were positive in every strain,and 16SrRNA methylase genes were positive in 5 strains.Furthermore,5 kinds of aminogly cosides modifying enzyme genes,a kind of 16SrRNA methylase gene,and 7 kinds of genetic markers of mobile genetic elements were positive in this group of CTX-ECO,and positive rates were high.Furthermore,sample cluster analysis showed that this group of CTX-ECO appeared obvious aggregation,and 6 clones existed.CONCLUSION All 30 strains of CTX ECO carrying blaCTX-M-55carried aminoglycosides modifying enzyme genes,16S rRNA methylase gene,and genetic markers of mobile genetic elements,and all played a key role in resistance to cephalosporins and aminoglycosides.Totally 6 clones in this group of CTX-ECO were suspected nosocomial infections,and every clone carried same genes.

关 键 词：大肠埃希菌 耐药 blaCTX-M-55 氨基糖苷类修饰酶基因 可移动遗传元件 样本聚类分析 

分 类 号：R378.21[医药卫生—病原生物学]