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1、37氨基甙类抗生素及多粘菌素(37aminoglycosideantibioticsandpolymyxin)Thefortiethchapter,aminoglycosideantibioticsandpolymyxinAminoglycosideantibioticsGeneralityof1.aminoglycosideantibiotics1).ChemicalstructureTheyareallcomposedofaminosugarmoleculesandaglyconeofnonsugarparts.Theyarestrongorganicacids,sol
2、ubleinwater,stableinnature,andoftenmadeintosulfateforclinicalapplication.2)antimicrobialspectrumForaerobicG-bacteria(E.coli,Klebsiella,Enterobacter),.Pneumonia,deformation,Salmonellaspp.anddrug-resistantstaphylococcusaureushavestrongeffectonG-coccus,suchasNeisseriagonorrhoeaeandNeisseriame
3、ningitidis.Amikacin,gentamicin,tobramycin,effectiveagainstPseudomonasaeruginosa,withstrongesttobramycin.Itisabactericideinreproductiveperiodandstationaryphase.3)mechanismofactionInhibitionofbacterialproteinsynthesisprocess,inhibitingtheformationof70sinitiationcomplexesintheinitialstage;int
4、hestageofpeptidechainelongationselectivelywith30SsubunitofP10proteinbindingtomRNAtemplategeneticcodemistranslation,synthesisofnonfunctionalproteins;terminationphaseterminationfactorandhinderribosomebinding,thesyntheticpeptidehasnotreleased70snuclearproteinbodydissociation,ribosomecelldeple
5、tion.Inaddition,aminoglycosidewasattachedtothecellsurfacebyionadsorption,resultingincellmembranedefects,andleakageofnutrientsinthecellanddeath.4)drugresistanceBacteriacanproduceresistancetoaminoglycoside,whichisarrangedfromeasytodifficultsequence,streptomycin>kanamycin>gentamicin>amikacin.
6、Somecrossresistanceamongthesedrugs,suchasstreptomycinresistantstrains,isstillsensitivetogentamicinoramikacin,butviceversa,Resistancetoamikacinwasalsoresistanttostreptomycinorgentamicin.Themaindrugresistancemechanismofbacterialproductionofinactiveenzyme,drugacetylation,phosphorylation,phosp
7、horylationandinactivationofadenosine,amikacinresistanttoavarietyofenzymes,soitisnoteasytoproducedrugresistance,inaddition,thebacteriacanalsochangethemembranepermeability,thedrugisnoteasyinfiltration,orchange30Ssubunitstructure,proteinP10deficiency,thedrugcanno