人卫7版微生物chapter7-细菌的感染与免疫课件

Chapter7

BacterialInfectionandimmunityBasictermsBacterialinfection（细菌的感染）Pathogen（病原菌）Nonpathogen（非病原菌）Opportunisticpathogen（机会致病菌）BacterialInfection细菌的感染Theprocessofbacteriainvadinginthebody,growinginthetissues,producingtoxinsandcausingdiseasesiscalledbacterialinfection.Opportunisticpathogen（机会致病菌）Conditionedpathogen（条件致病菌）Somebacteriaarecapableofcausingdiseasesonlyundercertainconditions.Theseorganismscancausediseaseonlyifoneormoreoftheusualdefencemechanismshumanshaveevolvedtorestrictmicroorganismsfromtheirusuallysterileinternalorgansandtissuearebreachedbyaccident,byintent(e.g.surgery),orbyanunderlyingmetabolicoraninfectiousdisorder(e.g.AIDS).OutlineNormalfloraandopportunisticpathogenBacterialpathogenesisThehostimmunedefencesystemTheinitiationandcourseofinfectionHospitalinfectionSection1

NormalfloraandopportunisticpathogenLocationsSurfacetissuesofskinOralcavityRespiratorytractGastrointestinaltractGenitourinarytractNormalfloraonintestinalmucosa肠道的正常菌群PrimeoflifeSenium★BeneficialeffectsofthenormalfloraBiologicalantagonism（生物拮抗）Productionofessentialnutrients（营养作用）Primingofimmunesystem（免疫作用）Anti-aging（抗衰老作用）Anti-tumor（抗肿瘤作用）Biologicalantagonism(生物拮抗)Biologicalbarriers（生物屏障）Receptorcompetition（受体竞争）Harmfulmetabolites（有害代谢产物）Nutrientcompetition（营养竞争）Conditionedpathogen（条件致病菌）Somebacteriaarecapableofcausingdiseasesonlyundercertainconditions.Thesebacteriaarecalledopportunistic(conditioned)pathogensandthiskindofinfectioniscalledopportunisticinfection（机会性感染）.★

Opportunisticpathogen（机会致病菌）Dysbacteriosis（菌群失调）Iffloradisequilibriumoccurs,forexample,whentheresidentfloraisdisturbed,somelittlesignificantmicroorganismsmaycolonize,proliferate,andproducedisease,whichiscalleddysbacteriosis.Dysbacteriosismainlyresultedfromlongtermandlargedoseantibioticstaken.Superinfection（重叠感染）Afrequentcomplicationofdrugtherapyformicrobialinfection.Itmayresultfromopportunisticcolonizationfollowingimmunosuppressionbytheprimarypathogenandcanbeinfluencedbythetimeintervalbetweeninfections,microbialphysiology,orhostresistance.DysbacteriosisandsuperinfectionProbiotics（益生菌）Probiotics（益生菌）&Prebiotics（益生元）Section2BacterialPathogenesisBasictermBacterialPathogenicity

BacterialvirulenceNumberofinvadingorganismsPortalofentryExotoxinPili(Fimbrial)CapsuleVirulentEnzymeAdhesinsFlagellaIronbindingproteinVirulencesurfaceproteinBacterialvirulencefactors（细菌毒力因子）Bacterialvirulence（细菌的毒力）Virulence（毒力）Invasiveness（侵袭力）Toxin（毒素）Adherence&permanentplanting（黏附与定植）Multiplication&diffusion（增殖与扩散）Anti-defensefunctionofhost（免疫逃逸）Endotoxin（内毒素）Exotoxin（外毒素）1.Adhesin（粘附素）Protiensonbacterialsurfaceassociatedwithadhesion.Adhesinsbindtoadhesinreceptorsonhostcells.Classification:Pili(fimbriae)adhesin(菌毛黏附素)Non-fimbriaeadhesin(非菌毛黏附素)AdhesionAdhesinEpitheliumReceptorBacteriumCapsule(荚膜)ofstreptococcuspneumoniaeMicrocapsule（微荚膜）

Slimelayer（黏液层）ProtectthecellwallagainstattackbydrugsInhibitingestionandkillingbyphagocytesPlayaroleintheadherenceofhumantissueAntigenicity2.Capsule（荚膜）3.Invasivesubstances（侵袭性物质）

Invasin（侵袭素）Encodedbyinvasivegenes（侵袭基因）MediateinvadingadjacentepithelialcellsInvasiveenzyme（侵袭性酶）Somebacteriamaygenerateinvasiveenzymes,whichcandamagebodytissuesandpromotetheinvasionanddiffusionofthebacteria.4.Bacterialbiofilm（细菌生物被膜）★Definition：Themembraneousbacterialcommunitycomposedofbacteriaandtheextracellularpolymerssecretedbybacteriaaftertheyadheretothesurfaceoflivingornonlivingmaterials.BacterialbiofilmFunctionsFacilitatesbacterialadhesionBafflesthepenetrationofantibioticandtherejectionofimmunesystemProfitssignalcommunicationamongbacteria.BacterialbiofilmBiofilmintheendoscope（内窥镜）Staphylococcusepidermidis（表皮葡萄球菌）biofilminthesurfaceofvenouscatheter（静脉导管）ExotoxinsEndotoxinsExcretedbylivingcells;highconcentrationsinliquidmedium.IntegralpartofthecellwallofG-bacteria.Releasedonbacterialdeathandinpartduringgrowth.Maynotneedtobereleasedtohavebiologicactivity.ProducedbybothG+andG-bacteria.FoundonlyinG-bacteria.PolypeptidesLPS(lipidAportionprobablyresponsiblefortoxicity.)Relativelyunstable;toxicityoftendestroyedrapidlybyheatingattemperaturesabove60℃.Relativelystable;withstandheatingattemperaturesabove60℃forhourswithoutlossoftoxicity.ExotoxinsEndotoxinsHighlyantigenic;stimulateformationofhigh-titerantitoxin(抗毒素).Antitoxinneutralizestoxin.Weaklyimmunogenic;antibodiesareantitoxicandprotective.Relationshipbetweenantibodytitersandprotectionfromdiseaseislessclearthanwithexotoxins.Convertedtoantigenic,nontoxictoxoids(类毒素)byformalin,acid,heat,etc.Toxoidsareusedtoimmunize.Notconvertedtotoxoids.Highlytoxic;fataltoanimalsinmicrogramquantitiesorless.Moderatelytoxic;fatalforanimalsintenstohundredsofmicrograms.ExotoxinsEndotoxinsUsuallybindtospecificreceptorsoncells.Specificreceptorsnotfoundoncells.Usuallydonotproducefeverinthehost.Selectivetoxicityandspecificclinicalsyndromes.Neurotoxins(神经毒素)Cytotoxins(细胞毒素)Enterotoxins(肠毒素)UsuallyproducefeverinthehostbyreleaseofIL-1andothermediators.Frequentlycontrolledbyextrachromosomalgenes(e.g.plasmids).Synthesisdirectedbychromosomalgenes.区别要点外毒素内毒素来源革兰阳性菌与部分革兰阴性菌革兰阴性菌编码基因质粒、前噬菌体或染色体基因染色体基因存在部分从活菌分泌出，少数菌崩解后释出细胞壁组分，菌裂解后释出化学成分蛋白质脂多糖稳定性60～80℃，30分钟破坏160℃，2～4小时破坏毒性作用强，对组织器官有选择性毒害效应，引起特殊的临床表现较弱，各菌的毒性效应大致相同，引起发热、白细胞增多、微循环障碍、休克、DIC等抗原性强，刺激机体产生抗毒素；甲醛液处理脱毒形成类毒素弱，刺激机体产生的中和抗体作用弱；甲醛液不能脱毒形成类毒素SpecificpolysaccharideLPSProcedureCytotoxins（细胞毒素）Diphtheriatoxin（白喉毒素）inhibitsproteinsynthesisinmammaliancellsandcausesnecrosisofcellsDiphtheriamembraneonthroatNeurotoxin（神经毒素）Tetanustoxin（破伤风毒素）Enterotoxin（肠毒素）

CholeraenterotoxinBiologicalrolesofendotoxinFever（发热）Leukopeniaandleukocytosis（白细胞反应）Endotoxemiaandshock（内毒素血症与休克）EndotoxinActivatesmacrophagesActivatescomplementActivatesHagemanfactorIL-1,TNF,NitricoxideFeverandhypotensionC3a,C5aHypotensionEdemaCoagulationcascadeDICSection4theinitiationandprocessofinfectionSourcesofinfectionPathwayofbacterialentranceTypesofbacterialinfectionExogenousinfection（外源性感染）PatientsCarriers（带菌者）AnimalsEndogenousinfection（内源性感染）OpportunisticpathogensSourcesofinfectionPathwayofpathogenentrance

RespiratoryGastrointestinalGenitalSkinandmucosaAnimalbitesBloodSexualtransmissionTypesofbacterialinfectionInapparentinfection（隐性感染）Apparentinfection（显性感染）Carrierstate（带菌状态）Inapparentinfection（隐性感染）Subclinicalinfection（亚临床型感染）Aninfectionthathasnoobservablesymptoms.Itoccurswhenthehostimmunityispotentorthepathogenicityofthepathogenisweak.Thetipoftheiceberg

Apparentinfection（显性感染）AcuteinfectionChronicinfectionLocalinfectionGeneralizedinfection★Toxemia(毒血症)Endotoxemia(内毒素血症)Bacteremia(菌血症)Septicemia(败血症)Pyemia(脓毒血症)Toxemia（毒血症）Bacteriamutiplyatinvadinglocationanddonotenterbloodstream,buttheexotoxins（外毒素）enterbloodandcausecorrespondingtoxicsymptoms.Endotoxemia（内毒素血症）Gram-negativebacteriamultiplyatlocationorinbloodstream,releasealotofamountendotoxin（内毒素）

releasedfrombacterialcellrupture.Bacteremia（菌血症）Afterenteringblood,bacteriacirculatebutnotmultiplyintheblood.Septicemia（败血症）Bacteriacirculateandmultiplyintheblood,inwhichbacteriaproducetoxicproductsandcausehighswingingtypeoffeverandothertoxicsymptoms.Pyemia（脓毒血症）Pyogenic（化脓性）bacteriaproducesepticemiawithmultipleabscess（脓肿）ininternalorganssuchasspleen,liverandkidneys.★

Carrierstate（带菌状态）Afterinapparentinfectionorapparentinfection,sometimesthepathogensarenoteliminatedintime,sothebacteriawillsurviveandmultiplyinhostatlowspeed,andbacteriaspreadintotheenvironment.Carrier（带菌者）isimportantsourceofinfection.HospitalinfectionDefinitionBasiccharacteristicsClassificationMicrobialecologicalcharacteristicsEpidemiologicalcharacteristicsRiskfactorsofNosocomialInfectionHospitalInfection（医院感染）Nosocomialinfection（医院内感染）Hospitalacquiredinfect