微生物致病及毒性的分子机制（英文ppt）molecular mechanisms of microbial pathogenesis and virulence课件

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1、MolecularMechanismsofMicrobialPathogenesisandVirulenceControllingInfectiousDiseasesThepre-antibioticEra-ImprovingSanitation&hygieneeducationTyphoid(Salmonella),Plague(Yersinapestis)Syphilis(Treponemapallidum)2.TheantibioticEra(1940-70)-Defeatofinfectiousbacter

2、ia?3.Post-antibioticEra-Emergenceandreemergenceofinfectiousdiseases.DeathsduetoTB(3million)&Diarrhea(3-4million)Legionnairesdisease(Legionellapneumoniae)LymeDisease(Borriellaburgdoferi)Gastriculcers&cancer:HelicobacterpyoriCampylobacterjejuni7strainsofE.coliVi

3、ralagents:SARS,Morbilli,HIV,HuntaWehavelostcontroloverinfectiousdiseases?Why?RoleofAntibiotics:Overuseofantibiotics/antimicrobialshasincreaseddrugresistantmicrobes;nonewantibioticshavebeendiscoveredinthepast20yrSomeexamplesofantimicrobialressistance:Pseudomona

4、saeruginosadominatehospitalburnunitsEmergenceofmultiple(methicillin)resistantstaphylococcusaureus(MRSA);Somestrainsarenowresistanttovancomycin,theonlyeffectiveremainingantibioticDecade2.Improvedstandardofliving:AirconditionersandLegionella3.Removingand/orsubst

5、itutingenvironments:SARS,HIV,Lymedisease4.Agingpopulation,compromisedimmunityMicrobesadapttothestressandpressureplacedonthem1.PhysiologicalAdaptation–Quorumsensing2.GeneticAdaptationVariousstagesofbacteriaeucaryotecellinteractionduringinfectionTrojanHorse:quor

6、umsensingPhysiologyAcquiringnewgenes-GeneticQuorumsensing-bacterialsignaling:LowmolecularweightcompoundsInhibitmacrophage&TlymphocytefunctioningAbletodeterminecelldensity-switchon/offgenesIncreasedensitytoaneffectiveinfectivitydosewithoutalertinghostofimpendin

7、gattack;pathogenesisgenesnotswitchedon.LegionellaincoolingtowersPathogenicmicrobessubvertfunctionsofhostsinmanyways:Hostsignaling,host-parasitesignaling;parasitesignalingAcquiringNewGenes-HorizontalGeneTransfer&GeneticRecombination1.HorizontalGeneTransferMecha

8、nisms:TransformationTransductionConjugation2.FateoftheTransferredGeneticMaterial:Incorporatedintothehostsgenome-themechanismNotincorporatedintothehostsgenome3.ConsequencesfortheHos