抗生素ppt课件（英文精品）

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1、AntibacterialsByI.R.Antibacterials/Antibiotics=Drugsthatpreventthegrowthof,orkill,microorganismsthatcauseinfectiousdiseases.Thesedrugsareselective,theyareineffectiveagainstnormalbodycells.Microorganisms=singlecelledlifeformscapableofindependentlifeifgivenarequiredamountofnutrients.I

2、nfectiousdiseases=Occurwhenthebody’snaturaldefensesareineffectivedueto1)lackofnaturalimmunesystemagainstinfection.2)toomanymicroorganismsforthebody’simmunesystemtoovercome.3)rapidgrowthofthemicroorganisms.InfectiousAgentsTherearetwotypesofinfectiousagents:BacteriaVirusesAntibioticsa

3、reineffectiveagainstvirusessincetheyincapableofcombatingnormalbodycells.AntibioticsaidwhitebloodcellsbyPreventingbacteriafrommultiplyingPreventingcelldivision(bacteriostaticdrugs)DirectlykillingBacteria(bacteriocidaldrugs)Examplesofbacterialinfections:tetanus,tuberculosis(TB),choler

4、a,etc.ExamplesofViralinfections:influenza,commoncold,hepatitis,etc.HistoryofPenicillins1890s:Foundoutthatcertainfungikilledbacteria.1928:AlexanderFlemingfindsoutthatthemoldpenicilliumnotatumpreventedthegrowthofthebacteriastaphylococcusaureus.1940:FloreyandChainusedpenicillinonmice.1

5、941:Penicillinusedforthefirsttimeonahumanbeing.1943:Penicillinavailableclinically.1945:Fleming,FloreyandChainreceiveNobelprize.AlexanderFleming,abacteriologistFloreyandChainrenewedFleming’sresearchStructureofPenicillinPenicillinG(firstpenicillinused):deactivatedby1)stomachacidinject

6、edintobody.2)Penicillinase,anenzymecreatedbybacteriaPenicillinV:acidresistantpenicillincreatedbymodifyingsidechains.Activepenicillin:Aminopenicillanicacid,6APA,(commoninallpenicillins)andasidechain:C6H5-CH2:benzylpenicillinorpenicillinGC6H5-CH2-CH2-:penicillinVCloxacillin,effectivea

7、gainstpencillinaseandacid.PenicillinGSpectrumofAntibioticsBroadspectrumantibiotics=onethatiseffectiveagainstawidevarietyofbacteria.Examples:AmpicillinTetracyclinessuchasAureomycinandTerramycin.‘Mycin’isthesuffixusedforantibioticsobtainedfromsoilfungi.Repeateduse:1)wipesoutharmlessba

8、cteria2)wipesouthel