抗生素耐药 resistance to antibiotics课件

《抗生素耐药 resistance to antibiotics课件》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、ResistancetoantibioticsIntrinsicresistance(examples)penGdoesnotentergramnegativebacteriawellwhy?doesn’tpenetrate--ampicillindoesrifampindoesn’tkillfungiwhy?doesn’tgetin---weakenbarrierwithamphotericinandthenitdoesisoniaziddoesnotkillbugsthatdon’trequiresyn

2、thesisofmycolicacidsEnvironmentalresistancee.g.sulfonamideresistanceifhighpurines,methionine,thymidineavailable(suchasinanabscess)e.g.aminoglycosidesnoteffectiveinanaerobicenvironmentAcquiredResistancegeneticchanges,plasmidswithnewgenes2006AntibiogramHarbo

3、rview/UWAcquiredDrugResistance1.enzymaticinactivation(b-lactams,aminoglyc.chloramph)Bacteriakeepupwithbigpharmaintheb-lactamantibioticarmsracebacteriacanoftenexpressmorethanone-lactamaseInactivationofaminoglycosidesbyacetylation,phosphorylation,andadenyla

4、tionindrug-resistantorganismsAcquiredDrugResistance1.enzymaticinactivation(b-lactams,aminoglyc.chloramph)2.rapideffluxofdrugoutofcell(tetracyclines,ciprofloxacin)DrugexportsystemsinGram+AcquiredDrugResistance1.enzymaticinactivation(b-lactams,aminoglyc.chlo

5、ramph)2.rapideffluxofdrugoutofcell(tetracyclines,ciprofloxacin)3.decreasedconversiontoactiveform(isoniazid)4.increasedconcentrationofantagonist/competitor(sulfonamideresistancewithincreasedPABAsynthesis).5.alteredamountofreceptor(trimethoprim-DHFRamplifica

6、tion)6.alteredstructureoftargettoreducebinding(methicillinresistance,vancomycinresistance,ciprofloxacinres.)Vancomycinresistance:mechanismVancomycinresistance:mechanismResistancecanbetransferredbetweenbacteriaphagetransductiontransposableelementsplasmidtra

7、nsferduringconjugationplasmidscancontainmultipleresistancegenestransfercanoccurbetweennon-pathogenandpathogensPlasmid-mediateddrugresistancechloramphenicolaminoglycosidesulfonamidetetracyclineProblemswithAntibioticresistancemorethan50%ofantibioticsusedindo

8、mesticanimalsforsub-therapeuticeffect:breedinggroundforresistanceThereare7.5billionchickens,292millionturkeys,109millioncattleand92millionpigsintheUnitedStates.Antibioticsgiventopigsasof2000“KFCdoesnotpurchas