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1、基本知识和耐药机制 1 MRSA 耐甲氧西林金黄色葡萄球菌 Multiple resistantStaphylococcusaureusOxacillin resistantStaphylococcusaureusCommunity acquiredMRSA CA MRSA Hospital acquiredMRSA HA MRSA MRSA是一种对甲氧西林和苯唑西林 青霉素和阿莫西林等 内酰胺类 到目前为止 抗生素耐药的金黄色葡萄球菌 其他名称包括 2 最常见的多重耐药微生物 MDRO s MRSA VISA VRSA VRE耐万古霉素肠球菌 Vancomycin resistantEnte
2、rococcusMDRTB多重耐药结核杆菌 Multi drugresistanttuberculosisQRGC Quinolone resistantgonococcusESBL超广谱 内酰胺酶 extended spectrumbeta lactamases resistanceseeninE coliandKlebsiellaPRP青霉素耐药肺炎链球菌 PISP青霉素中敏肺炎链球菌AmpC非发酵菌 铜 不动 金属酶嗜麦芽窄食单胞菌 3 金葡菌耐药性的出现时间 年 Chambers EID7 178 182 2001 4 5 MRSA mechanism MSSA MRSA Newpep
3、tidoglycan Cross linkedwall PBPs1 2 3 Newpeptidoglycan Cross linkedwall PBPs1 2 3 PBP2 青霉素结合蛋白2 6 金葡菌 为什么如此让我们担心 致病性PathogenicityCommunityinfectionsFuruncles boils carbuncles endocarditis toxicshock传播性TransmissibilityColonized inadditiontoinfected personssourcesoftransmission耐药性ResistanceDecreasingt
4、reatmentoptions 7 金葡菌感染的病理生理 定植Colonization局部感染Localinfection全身播散 脓毒症Systemicdisseminationand orsepsis转移病灶Metastaticinfection毒血症Toxinosis 8 毒力因子VirulenceFactors MRSA VRSA andVISAshareallofthesamevirulencefactorswithantibioticsusceptibleS aureus Additionally VISAstrainsshowlongerdoublingtimesandreduc
5、edautolyticactivitiesVRSAandMRSAproducepenicillinbindingproteins2and2 Reducedcrosslinkingincellwallsthroughglutamineamidation 9 CA MRSA携带PVL基因 117CA MRSA株33美国67欧洲 61法国6瑞士 17太平洋 Australia NewZealand WesternSamoa 多分离自皮肤和软组织感染所有菌株携带Panton Valentineleukocidin位点不同地区携带其他不同的毒素基因 Vandeneschetal EmergingInfe
6、ctiousDiseasesVol 9 No 8August2003 10 PVL与原发性皮肤感染和肺炎 172SA检测PVL基因93 疖 furunculosis 85 重症坏死性出血性肺炎 severenecrotichemorrhagicpneumonia 55 蜂窝组织炎 cellulitis 50 皮肤脓肿 cutaneousabscess 23 骨髓炎 osteomyelitis 13 指节感染 finger pulpinfection Notdetected infectiveendocarditis mediastinitis hospital acquiredpneumoni
7、a urinarytractinfection enterocolitis toxic shocksyndrome Linaetal ClinInfectDisNovember1999 既往健康的14例CA MRSA11皮肤或软组织感染2死于坏死性肺炎 necrotizingpneumonia 均检测出PVL Panton Valentineleukocidin 基因Dufouretal ClinInfectDis2002 35 000 000 11 MRSA传播 12 金葡菌定植StaphylococcusaureusColonization 人自然携带Humansnaturalreserv
8、oirAnteriornares30 50 healthyadultscolonizedatanyonetime 60 colonizedintermittently 20 persistentlycolonized 20 nevercolonizedAxillae vagina pharynx damagedskin rectumHands intactskincolonizedtransientlyClearanceofnasalcolonizationeliminateshand skincarriage 13 From Kluytmansetal ClinMicrobiolRev Ju
9、ly1997 不同人群鼻部金葡菌定植率RatesofS aureusnasalcarriageinvariouspopulations 14 大多数的革兰阳性菌 如肠球菌 包括耐V万古霉素肠球菌VRE 金黄色葡萄球菌 包括耐甲氧西林葡萄球菌MRSA 化脓性链球菌等 都能在干燥环境中存活数月之久 环境中细菌存活时间 15 葡萄球菌和肠球菌在织物和其他表面存活时间 JClinMicrobiol 2000February 38 2 724 726 16 表与临床相关的细菌在干燥环境中的保存时间 17 MRSA可见于任何地方 The5c sCrowdingFrequentskin to skinCon
10、tactCompromisedskin i e cutsorabrasions ContaminateditemsandsurfacesLackofCleanliness CommonlocationsSchoolsDormitories宿舍MilitarybarracksHouseholdsCorrectionalfacilitiesDaycarecenters 18 比一比 看一看 19 MRSA在医务人员中定植 6 2 ofHCWswerefoundtobenasalcarriersofMRSAina600 bedhospital4of10MRSA positiveHCWsstudied
11、hadtransmittedtofamilymembersEveillardetal CarriageofMethicillin ResistantStaphylococcusaureusAmongHospitalEmployees Prevalence Duration andTransmissiontoHouseholds InfectControlHospEpidemiol 2004Feb 25 2 114 20 20 MDRO s的传播 直接接触与间接接触人 人传播尤其是手接触污染的环境呼吸道飞沫直接 间接 环境被呼吸道飞沫污染 21 与金黄色葡萄球菌感染或定植者皮肤 皮肤接触接触有黄
12、色葡萄球菌的物品或物体表面皮肤开放性病变居住 住院 环境拥挤卫生条件差尤其是手卫生 Incubationperiodfromexposuretoinfectiondependsonmanyfactors 传播方式 22 医院内获得性MRSA 85 MRSA感染发生在医疗机构医院外2 3发生在福利院 家庭护理 透析中心和诊所在医院内20 的血流感染由金黄色葡萄球菌引起 23 金葡菌医院内传播Transmission Pathogenesis NosocomialMRSA 抗生素 阴性病人 定植 感染 皮肤破损侵入性设施 免疫抑制 24 社区获得性MRSA CommunityAssociatedM
13、RSA CA MRSA MRSA感染是指过去一年内没有住院或者没有如透析 手术 留置导管等医疗操作的人员感染MRSA CDC发生在基于社区的环境社区分离株更敏感 25 CA MRSA监测定义 入院48小时内培养分离到MRSA 如果住院 一年内无住院史Nohistoryofhospitalizationinpastyear一年内无手术史Nohistoryofsurgeryinpastyear一年内无住福利院史Nohistoryoflong termcareinpastyear一年内无透析史Nohistoryofdialysisinpastyear无持久的留置导管史或侵入性医疗设施操作Noperm
14、anentindwellingcathetersorpercutaneousmedicaldevices以前未感染或定植MRSANopriorhistoryofMRSAinfectionorcolonization 26 CA MRSA 与医院MRSA的差异ClinicalSkinandsofttissueinfectionsEpidemiologyChildrenandyoungadults summertimePrisons IVDU sportsteams aboriginalpopulationsPhenotypeMono resistant non MDR rapidgrowthGe
15、notypeTypeIVSCCmecgene PVLandothervirulencefactors PFGEpatterns EpidemiologyNonationalsurveillanceEmergedin1980s increasing epidemiclevels PathogenicityMorepathogenic transmissiblethanHA MRSADifferentfromCA MSSA RiskfactorsLimitedstudiessuggestfewidentifiableriskfactorsAntibioticuseusuallynotariskfa
16、ctor 27 CA MRSA的医院内传播 HospitalTransmissionofCA MRSAamongPostpartumWomenDepartmentsofPediatrics ColumbiaUniversity NewYork8womenskinandsoft tissueMRSAinfectionsmeantimeof23days range 4 73days afterdelivery4casesofmastitis 3progressedtobreastabscess apostoperativewoundinfection cellulitis pustulosisIdenticalbyPFGEtoCA MRSAstrainMW2Routeoftransmissionnotdiscovered culturesfromemployeesofthehospital thehospitalenvironment andnewbornsnegativeSaimanetal ClinInfectDis 2003Nov15 37 10 1313 9 28 CA MRSA监
