多粘菌素耐药基因mcr-1课件

Complexdisseminationofthediversifiedmcr-1-harbouringplasmidsinEscherichiacoliofdifferentsequencetypes

多粘菌素耐药基因mcr-1质粒的多样性及复杂传播机制王艳艳Emergenceofplasmid-mediatedcolistinresistancemechanismMCR-1inanimalsandhumanbeingsinChina:amicrobiologicalandmolecularbiologicalstudyYi-YunLiu*,YangWang*,TimothyRWalsh,Ling-XianYi,RongZhang,JamesSpencer,YoheiDoi,GuobaoTian,BaoleiDong,XianhuiHuang,Lin-FengYu,DanxiaGu,HongweiRen,XiaojieChen,LuchaoLv,DandanHe,HongweiZhou,ZisenLiang,Jian-HuaLiu,JianzhongShen目前发现多黏菌素耐药机制two-componentsystems[pmrAB[6]andphoPQ[7])andtheregulatormgrBtheplasmid-mobilizedcolistinresistance(MCR-1)SincethefirstdiscoveryofMCR-1fromSouthernChina,inthelateof2015,thenewcolistinresistancegenehasspreadto5of7continentsnolessthansixspeciesofEnterobacteriaceae(E.coli,Enterobacteraerogenes,Enterobactercloacae,K.pneumonia,Salmonellaenterica,andShigellasomneiarerecipienthostsforthemcr-1-harbouringplasmidsMoreseriously,theMCR-1wasfoundtoco-localizewithtwotypesofnotoriousdrugresistantgenes(ESBLandNDM-1(and/oritsmutants).

菌株的收集与鉴定

主要内容mcr-1基因所处的质粒骨架呈现出多样性与复杂性质粒骨架上插入序列、转座子等移动元件的发现，表明其移动散播机制的复杂性。检测到的质粒均位于E.coli中，对菌株进行MLST分型发现其ST呈现出多样化，具有11种序列型，并且发现了一种新的ST类型。通过构建报告基因LacZ基因的融合，率先分析了mcr-1基因启动子的活性。MLST分型发现其ST呈现出多样化β-GalactosidaseassaysThestrainsofE.colicarryingthechromosomePmcr-1-lacZtranscriptionalfusion(e.g.,FYJ853)weregrowninLBmedia,andmid-logphasecultureswerecollectedassayedforβ-galactosidaseactivityfollowinglysiswithSDS(sodiumdodecylsulfate)-chloroform.小结Insummary,itseemslikelythatcomplexdisseminationofthediversifiedmcr-1-harbouringplasmidsoccursamongstthevariousSTE.coliinhabitingthehealthyswinepopulations,inSouthernChina.Inparticular,ourfindingshighlightedtheurgentneedtoreconsidertheefficacy(safety)ofcolistinintheveterinaryuse,andformulateacomprehensivestrategytofightagain