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1、TopicalAntibioticsTopicalantibioticshelppreventinfectionscausedbybacteriathatgetintominorcuts,scrapes,andburns.Treatingminorwoundswithantibioticsallowsquickerhealing.Ifthewoundsareleftuntreated,thebacteriawillmultiply,causingpain,redness,swelling,itching,andoozing.Untreatedinfectionscanevent
2、uallyspreadandbecomemuchmoreserious.Whichbacteria?MosttopicalantibioticsaredirectedagainstStaphylococcusaureusandStreptococcuspyogenes.TheanaerobicGram-positivebacterialspeciesPropionibacteriumacneshasbeenlinkedtoacne.Whichtopicalantibioticsarecommon?Somewidelyusedtopicalantibioticsarebacitr
3、acin,neomycin,mupirocin,andpolymyxinB.AmongtheproductsthatcontainoneormoreoftheseingredientsareBactroban(aprescriptionitem),Neosporin,Polysporin,andTripleAntibioticOintmentorCream.ClassesoftopicalantibioticsCellwallsynthesisinhibitorsRibosomefunctioninhibitorsSulfadrugsBurntreatmentagentsMis
4、cellaneousMupirocin(90%PseudomonicacidA)IsolatedfromPseudomonasfluorescensAntibacterialactivityofsubstancefromP.fluorescensnotedin1887Purifiedinthe1960’s.MupirocinworksagainstGram-positivebacteriaonlyCanbeusedtotreatMRSA(althoughresistanceisrising)Esterlinkageisrapidlyhydrolyzedhepatically,t
5、husprecludingutilityasanoralorintravenousantibioticMupirocininhibitsbacterialisoleucyl-tRNAsynthetase.ProductscontainingMupirocinPolymyxinBPolymixinBMemberofthelipopeptideclassofantibiotics,similartodaptomycinDaptomycinPolymixinBPolymyxin:AntibacterialactivityHowever,thepolymyxinsareonlyacti
6、veagainstgramnegativebacteria(P.aeruginosa,E.coli,K.pneumoniae),whiledaptomycinisusedtotreatgrampositivebacteriaThepolymyxinsarehighlynephrotoxicandarethusonlyusedtopicallyPolymyxins:MechanismofactionBindthethelipopolysaccharideintheoutermembrane,thusdestroyingOMintegrity.Bindtothecytoplasmi
7、cmembrane(tothephosphatidylethanolamine)andmakethemembranemorepermeable.ProductscontainingpolymyxinBBacitracinABacitracin:HistoryIsolatedbyJohnT.Goorleyin1943FoundintheinfectedcompoundfractureofthepatientMargaretTracyBacitracin:AntibacterialActivit
