antimicrobial agents课件

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1、AntimicrobialAgentsMechanismsofActionandSpectraofActivityOBJECTIVESDescribemajorclassesofantimicrobialsandtheirmechanismsofactionKnowthespectraofactivityofcommonlyusedantibioticsUnderstandthemechanismsofresistancetoantibioticsKnowtheprincipleandrationalebehindantibioticsusceptibilitytestingOverview

2、ofAntibioticsasTherapeuticAgentsSelectiveInhibition/ToxicityDuetothedifferencesinstructureandmetabolicpathwaysHarmmicroorganisms,notthehostFourmajorsites:CellwallRibosomesDNACellmembraneSpectrumofActivityBroadSpectrumAntibiotics:EffectiveagainstmanytypesExample:TetracyclineNarrowSpectrumAntibiotics

3、:EffectiveagainstveryfewtypesExample:PenicillinBactericidalv.BacteriostaticBactericidal:KillbacteriaUsedwhenthehostdefensemechanismsareimpairedRequiredinendocarditis,kidneyinfectionBacteriostatic:InhibitbacteriaUsedwhenthehostdefensemechanismsareintactUsedinmanyinfectiousdiseasesMECHANISMSOFACTIONO

4、FMAJORGROUPSOFANTIBIOTICSSTRUCTUREOF-LACTAMANTIBIOTICSPENICILLINHOME“PenicillinHome”LookslikeahousewithanewroomaddedtothesideThinkoftheR-groupasofafunkyantennaChanging“antennae”andorfinishingthe“basement”willcreatebetter“homes”(penicillins)[Penicillin]HomeImprovementProjectAddinganewantennacreates

5、broadspectrumpenicillinsExample:AmpicillinAddingadditionalantennaeandfinishingthebasementcreatescephalosporinsExample:1st,2nd,3rd,&4thgenerationcephalosporinsSPECTRUMOFACTIVITYOFCEPHALOSPORINSMECHANISMOFACTIONOF-LACTAMANTIBIOTICS-lactamantibioticsareineffectiveagainstprotoplastsandspheroplasts:A.

6、TRUEB.FALSEMECHANISMSOFACTIONOFANTIRIBOSOMALANTIBIOTICSInhibitionofProteinSynthesisAnti-ribosomalantibioticsimpairribosomesbybindingtoeither50Sor30SribosomalsubunitsRibosomesareessentialfortranslationofmRNAintoproteinsNotranslationNoproteinsynthesisNoproteinsynthesisNogrowthRibosomeHomePlateBase

7、ballplayerslidesintohomeTheballisfieldedbythecatcherwhomakesaCLEanTAGThewordCLEeanliesoverthebase:theseinhibit50SThewordTAGliesbeneaththebase:theseinhibit30SHowarethesedrugsadministered?MECHANISMOFACTIONOF