英文版-Indiana-University-Purdue-University-Fort-Wayne微生物学授课讲义-lecture-12课件

EnterobacteriaceaeBIOL533Lecture12MedicalMicrobiologyBIOL5331EnterobacteriaceaeBIOL533MediEnterobacteriaceaeDiversityofspeciesEcologyFoundworldwideinsoil,water,vegetation,andmicrobialfloraofanimalsandhumansSomearealwaysassociatedwithdiseasee.g.,Shigella,Salmonella,YersiniapestisSomearenormalflorathatcanbecomeopportunisticpathogense.g.,E.coli,K.pneumoniae,P.mirabilisBIOL5332EnterobacteriaceaeDiversityofEnterobacteriaceaeEpidemiologyAnimalreservoir:mostSalmonellainfectionsHumancarrier:Salmonellatyphi,ShigellaEndogenousspreadinasusceptiblepatientCaninvolveallbodysites5%hospitalizedpatientsdevelopnosocomialinfections,primarilycausedbyEnterobacteriaceaesuchasEscherichiaSitesofinfectionBIOL5333EnterobacteriaceaeEpidemiologyMicrobialPhysiology

andStructureCellmorphologyModerate-sizedGram—rodsNon-spore-formingMotile(withperitrichousflagella)ornon-motilePhysiologyAllarefacultativeanaerobesSimplenutritionalrequirements:FermentglucoseReducenitratestonitritesBIOL5334MicrobialPhysiology

andStruDistinguishingCharacteristicsOxidase¯:Distinguishesamongotherfermentativeandnon-fermentativeGram—bacilliLactosefermentation(redcoloniesonMacConkeyagar)SeparateEscherichia,Klebsiella,Enterobacterfromotherlactose—EnterobacteriaceaeBIOL5335DistinguishingCharacteristicsDistinguishingCharacteristicsResistancetobilesaltsSeparateShigellaandSalmonellafromnormalflorainthisgroupEosinMethyleneBlue(EMB)Lactose,eosinY,methyleneblue;Lac+;growwithgreensheenBIOL5336DistinguishingCharacteristicsVirulenceFactorsAntigensSomatic“O”LPSMajorcellwallAg;heatstableSpecific“O”antigensassociatedwitheachgenus;however,crossreactionsarecommonSalmonellaandCitrobacterEscherichiaandShigellaBIOL5337VirulenceFactorsAntigensBIOLVirulenceFactorsCapsularKEitherproteinorpolysaccharideHeat-labileMayinterferewithdetectionof“O”RemovedbyboilingorganismsCapsularantigenofSalmonellatyphireferredtoasViantigenBIOL5338VirulenceFactorsCapsularKBIOVirulenceFactorsCapsularK,continuedSharedbydifferentgenerabothinsideandoutsideoffamilyCrossreactionsE.coliK1withN.meningitidisandHaemophilusmeningitidisK.pneumoniaewithS.pneunomiaeOrganismswithspecificantigenshavebeenassociatedwithincreasedvirulence (e.g.,E.coliK1withneonatalmeningitis)BIOL5339VirulenceFactorsCapsularK,cVirulenceFactorsFlagellaHHeat-labileproteinsCanbeabsentorundergoantigenicvariation(presentintwophases)SpecificHantigensassocatedwithdiseaseBIOL53310VirulenceFactorsFlagellaHBIOVirulenceFactorsGeneralroleinpathogenesisof“O,”“K,”and“H”antigensSpecificantigensassociatedwithmeningitis,gastroenteritis,andurinarytractinfectionsRolethatAg’splayinthesediseasesisnotclearSomecapsularAgarepoorimmunogensProtectagainstantibody-mediatedphagocytosisFlagellarAgprobablyplayaroleinadherenceBIOL53311VirulenceFactorsGeneralroleVirulenceFactorsPiliAttachmenttohostcellsBIOL53312VirulenceFactorsPiliBIOL5331PathogenesisofEscherichiaE.colipresentingastrointestinaltractinnormalfloraBacterialsepsis(multiplicationinblood)Primaryfocus-infectionofurinarytractorspreadfromgastrointestinaltractDeathcanoccurinimmunocompromisedpatientsandinfectionsresultingfromintestinalperforationBIOL53313PathogenesisofEscherichiaE.PathogenesisofEscherichiaNeonatalmeningitisE.coliandgroupBstreptococcimostcommon75%E.colipossessCapsularK1antigenColonizationofinfantswithE.coliatdeliveryiscommon;diseaseisnotBIOL53314PathogenesisofEscherichiaNeoPathogenesisofEscherichiaUrinarytractinfections (80%communityandmostnosocomial)OriginatefromgastrointestinaltractImportantvirulencefactorsResistancetoserum-killingProductionofhemolysinsPili-mediatedbinding(notdemonstratedinvivo)ProductionofslimelayerthatparticipatesincelladhesionBIOL53315PathogenesisofEscherichiaUriPathogenesisofEscherichiaGastroenteritis (countrieswithpoorhygiene)Enterotoxigenic(ETEC)Mediatedbyheat-labile(likecholera)andheat-stableexotoxins(activatesguanylatecyclaseandstimulatessecretionoffluid)Botharecodedfromplasmid-bornegenesWorld-wide:bothadultsandchildrenIncubation1-2days;persists3-4daysMildsymptoms,includingcramps,nausea,vomiting,waterydiahrreaBIOL53316PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteroinvasive(EIEC)InvadeanddestroycolonicepitheliumFeverandcrampswithbloodandleukocytesinstoolUncommon;oftenfood-borneEnteropathogenic(EPEC;childhooddiarrhea)OrganismadherestoenterocyteplasmamembraneandcausesdestructionofmicrovilliproducingwaterydiarrheaAdhesivenessmediatedbyplasmid-encodedpiliBIOL53317PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteropathogenic(continued)Infants<1yearaffectedEnterohemorrhagic(EHEC;hemorrhagiccolitis)Producescytotoxin(verotoxin)Severeabdominalpain,bloodydiarrhea,littleornofeverWarmmonthsofyear;affectschildren<5yearsBIOL53318PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteroaggregative(EaggEC;waterydiarrhea)Infants<6monthsAIDSpatientsBIOL53319PathogenesisofEscherichiaGasPathogenesisofDifferentToxinsCholeraandETECColonizemucosalsurfacebytoxincoregulatedpilus(cholera;TcpA)orcolonizationfactorAg(Cfa;E.coli)CtxorLTbindstoreceptorandtakenupbyvesicles;transportedfrombasolateralmembranetoACcomplexBIOL53320PathogenesisofDifferentToxiPathogenesisofDifferentToxinsCholeraandETEC(continued)ADP-ribosylationyieldscAMP(cholera-like)ETEC(heatstable;ST)bindstomembrane-boundguanylatecyclasecomplexthatproducescGMPBothcAMPandc-GMPreduceNa+absorptioninviluscellsIncreaseCI—secretionincryptcells;yieldswaterydiarrheaBIOL53321PathogenesisofDifferentToxiPathogenesisofDifferentToxinsEPECAttachestosmallbowelbybundleformingpilus(BfpA)BindingyieldssignaltransductioneventsPhosphorylationofmajorepithelialproteinHp-90ActivationphospholipaseCIncreaseinositoltriPO4(IP3)andCaDamagetomicrovilliBIOL53322PathogenesisofDifferentToxiPathogenesisofDifferentToxinsEPEC(continued)Intiminmediatesintimiteassociation39kDaproteincausespolymerizationofactinandothercytoskeletalproteinsandrearrangementofcytoskeletalstructureFormcharacteristicEPECpedestal(attachingeffacinglesion)withintimatelyattachedorganism;notknownhowhostgetsdiarrhea)BIOL53323PathogenesisofDifferentToxiPathogenesisofDifferentToxinsInterestingly,E.coli0:157H:7haspedestalandShigatoxin(char.Shigella)BIOL53324PathogenesisofDifferentToxiPathogenesisofSalmonellaSourceofmostinfectionsIngestionofcontaminatedwater,foodPoultry,eggs,anddairyproductsSalmonellatyphispreadbyfoodorwater;contaminatedbyfood-handlersNeedtoingestlargenumberoforganisms(106-8)Byfecal-oralcontactinchildrenBIOL53325PathogenesisofSalmonellaSourPathogenesisofSalmonellaGastroenteritis(mostcommon)Symptoms6-48hoursafteringestionNausea,vomiting,non-bloodydiarrheaElevatedtemperature,abdominalcramps,musclecramps,headacheSymptomspersistfor2daystoaweekbeforeabatingAntibioticsarenormallynotemployedbecausecarrierstatecandevelopBIOL53326PathogenesisofSalmonellaGastPathogenesisofSalmonellaGastroenteritis(continued)Moreacid-sensitivethanShigellaInfectpatientswithdecreasedstomachacidLargeinoculumneededDecreasedby10-100XinthepresenceofbicarbonateBIOL53327PathogenesisofSalmonellaGastPathogenesisofSalmonellaSepticemia(pediatricandgeriatricpatients)10%patientscanget:osteomyelitis,endocarditis,orarthritisBIOL53328PathogenesisofSalmonellaSeptPathogenesisofSalmonellaEntericfever (S.typhi,typhoid;S.paratyphi,paratyphoid)ParatyphoidismilderSymptomsafter10-14dayincubationperiodGraduallyincreasingremittantfeverHeadache,muscleaches,malaise,anddecreasedappetite;gastrointestinalsymptomsoccurSymptomspersistforafewdaysBIOL53329PathogenesisofSalmonellaEntePathogenesisofSalmonellaEntericfever(continued)Carriers(“TyphoidMary”)1-5%ofpatientswillcarryafterayearGallbladder-primarysourceBIOL53330PathogenesisofSalmonellaEnteMechanismofPathogenesisSenseacidenvironmentproduces~40proteinswithimportancetopathogenesisOrganisimsescapekillingin:smallbowel,anddistalilleumofcolonPenetratemucosalbarrier;notclearwhetherinvolves:Mcells-OR-apicalmembraneofgutepithelialcells-OR-TightjunctionbetweencellsBIOL53331MechanismofPathogenesisSenseMechanismofPathogenesisSenseacidenvironment(continued)Contactoforganism’scellsincultureproducingrufflingofplasmamembrane(cytoskeletalrearrangements)leadtouptakeintophagocyticvesiclesInteractionwithepithelialcellsactivatesinflammatoryresponseyieldingdamagetointestinalmucosaBIOL53332MechanismofPathogenesisSensMechanismofPathogenesisInteractionwithepithelialcells(continued)Assemblynon-piliappendages(15minutes)S.typhimurium14genesofinvoperonIn30minutes,rufflesappearBacterialappendagesdisappearAssemblymutants:bothassemblyanddisassemblyinvAEassemble;neverdisassembleinvCGneverassembleBIOL53333MechanismofPathogenesisInterMechanismofPathogenesisBiochemicaleventsactivatedduringinvasionActivation:mitogenactivatedProteinkinase(MAPkinase)LinkedtosurfacereceptorBindingproducesactivationPhospholipaseA2(PLA2)ReleasearachidonicacidProduceprostaglandinleukotrienesIncreaseinintracellularCa+2BIOL53334MechanismofPathogenesisBiochMechanismofPathogenesisBiochemicalevents(continued)Alltheseproduceruffling,butalsoalterelectrolytetransportleadingtodiarrheaBacteriaremaininvesiclesforhoursResistanttolysosomalcontentsandantibacterialpeptidesmadebyintestinalepithelialcells(cryptins)MovefromvesiclestobasementmembraneleadingtolaminapropriaBIOL53335MechanismofPathogenesisBiocMechanismofDiarrheaExactmechanismofdiarrheaunknownInvasionproducesIL8thatleadstolocalleukocyteattractionAbilitytoinvadeandproduceinflammationnecessary,butnotsufficienttoproducediarrhea;foundbyexperimentsinanimalsOthersignalnecessarySomehavecholeratoxin-likemoleculeBIOL53336MechanismofDiarrheaExactmecPathogenesisofS.typhiTyphoidFeverSurviveinmacrophage;studiedinmiceCausestyphoid-likeillnessinmice;diarrheainhumansBIOL53337PathogenesisofS.typhiTyphoiPathogenesisofS.typhiVirulenceregulatedsignaltransduction(PhoP/PhoQ)MutationsDecreasedsurvivalinmacrophageIncreasedsensitivitytoacidpHSensitivitytomammalianantimicrobialpeptidesAttenuationofvirulenceBIOL53338PathogenesisofS.typhiVirulePathogenesisofSalmonellaInvasivenon-typhoidalstrainsVirulenceplasmid8kbconservedSalmonellaplasmidvirulencegenes(spv)Turnedon:whenentereukaryoticcellsresistancetocomplementBIOL53339PathogenesisofSalmonellaInvaPropertiesofShigellaSpeciesShigellasonnei(industrialcountries)Shigellaflexneri(underdevelopedcountries)Pediatricdisease(1-4years)Associatedday-carecenters,nursuries,andcustodialinstitutionsSpreadbyfecal-oralroute(hands)200bacillicanestablishdiseaseBIOL53340PropertiesofShigellaSpeciesBPropertiesofShigellaClinicalsyndromes(1-3daysafteringestion)AbdominalcrampsDiarrheaFeverBloodystoolsBIOL53341PropertiesofShigellaClinicalPropertiesofShigellaPathogenesisColonizesmallintestineandmultiplyduringfirst12hoursInitialsignofinfection—profusewaterydiarrheawithouthistologicalevidenceofmucosalinvasionMediatedbyenterotoxinInvasionofcolonicepitheliumresultsinlowerabdominalcramps,difficultydefecating,abundantpusandbloodinstoolBacteremiaisuncommonBIOL53342PropertiesofShigellaPathogenAntibioticTherapyofShigellaAntibiotictreatmentisrecommendedtoreducespreadtoothercontactsFluoroquinolines-adultsUnder17-damagetocartilageandjointsDeterminedbyanimalstudiesFDAdoesnotallowuseinchildrenNew-lactamcephalosporininuseBIOL53343AntibioticTherapyofShigellaPathogenesisofShigellaSurvivalinstomachSenseacidenvironmentSigmafactorRNApolymerase(formedinstationaryphase)BIOL53344PathogenesisofShigellaSurvivPathogenesisofShigellaSurvivalinstomach(continued)Controlsgroupofgenesconcernedwithacidresistance;acidresistanceincreasedInvasion-abilitylessWhenreachsmallintestine,invasionabilityreturnsandacidresistancerepressedAcidresistanceenhancedbyanaerobicconditionsfoundinlargeintestineLikelywhenexcreted:acid-resistanceisexpressed;readyfornexthostBIOL53345PathogenesisofShigellaSurvivLargeIntestineInvasionBacterialmultiplicationoccursinsideintestinalepithelialcellInvasionandsurvivalmultiplegenesbothonchromosomeandplasmid(largevirulence)BIOL53346LargeIntestineInvasionBacterLargeIntestineInvasionInvasionstepsGetclosetomucosalsurface(unknownmechanism);noflagella;non-motile;cellscan’tbeinvadedonluminalsurface,butcanbeonbasalFirstenterMcells(Agsamplingcells)DependsonplasmidcodedoutermembraneproteinsInvasionplasmidAg;IpaBCDBIOL53347LargeIntestineInvasionInvasiLargeIntestineInvasionInvasionsteps(continued)Releasedintolaminapropria(intercellularspace)ingestedbymacrophageTheyreleaseIL1thatproducesinflammatoryresponse;increasesubsequentinvasionclosetobasalsurfaceEntryofShigellaintomucosalepithelialcells;rearrangementofactincytoskeletalelementsBIOL53348LargeIntestineInvasionInvasiLargeIntestineInvasionInvasionsteps(continued)GofromphagosomeintocytoplasmandmutipliesHowdotheyinfectothercells?Astheymultiply,theymakeproteinIcsAthatcausesintracellularspreadof1poleofrod;ATPasecausespolymerizationofactin(host)BIOL53349LargeIntestineInvasionInvasiLargeIntestineInvasionDepositionofactinpropelsbacteriaforwardFingerlikeprojectionpokesadjacentcellSurroundedbyacombinationofoldandnewmembrane;produceslysisandentryoforganismintocytoplasmofnewcellBIOL53350LargeIntestineInvasionDeposi

S.dysenteriaePathogenesis

S.dysenterieaetype1alsopossesses:shigatoxincytotoxin-killsintestinalepithelialandendothelialcellsBIOL53351S.dysenteriaePathogenesis

S.dysenteriaePathogenesisShigatoxinIrreversiblyinactivatesmammlian60SribosomalSU;stopsproteinsynthesisMechanism:Targetssodiumabsorptivevilluscell;producesdecreaseinNa+absorption;morefluidaccumulatesinlumenAffectstoxinmucosalepithelialcellsyieldingbloodydiarrheaBIOL53352S.dysenteriaePathogenesis

S.dysenteriaePathogenesisInfectionsinmonkeysStrainswithinactivatedShigatoxingenecausediseasewithmuchlessdamagetomucosaandlessbleeding;therefore,bothinvasionandtoxinformationareimportantS.dysenteriaetype1mostsevereS.flexnericausessevereillnesswithdysenteryandbloodydiarrhea;hasnogenesforShigatoxinBIOL53353S.dysenteriaePathogenesisI

S.dysenteriaePathogenesisInterestingly,S.sonneihassameinvasionprocessasothertwo,butwithnodysentery,onlywaterydiarrheaReasonfordifferencebetweentype1andothersmaybedifferenceinintensityofinflammatoryresponseBIOL53354S.dysenteriaePathogenesisInPathogenesisof

YersiniapestisClincalsyndromesBubonicplague(incubationperiod-7daysafterbitefrominfectedflea)HighfeverandinflammationoflymphnodesingroinorarmpitAbsenceoftreatment—bacteremia(75%die)BIOL53355Pathogenesisof

YersiniapestPathogenesisof

YersiniapestisClincalsyndromesPneumonicplague(incubation2-3days)HavefeverandmalaiseDeveloppulmonarysymptomswithin1dayUntreated>90%dieBIOL53356Pathogenesisof

YersiniapestPathogenesisof

YersiniaenterocoliticaAssociatedwithContaminatedmeatormilkColderclimatesduringwintermonthsBIOL53357Pathogenesisof

YersiniaentePathogenesisof

YersiniaenterocoliticaGastroenteritisDiarrhea,fever,abdominalpainLastingfor1-2weeksChronicformcanpersistformonthsoryearCanmimicappendicitis,particularlyinchildrenAdultscanhavesepticemia,arthritis,intrabdominalabscess,hepatitis,andosteomyelitisBIOL53358Pathogenesisof

YersiniaentePathogenesisof

KlebsiellapneumoniaeAssociatedpneumoniaFrequentlyassociatedwithNecroticdestructionofalveolarspacesProductionofblood-tingedsputumCanalsocausewound,softtissue,andurinarytractinfectionsBIOL53359Pathogenesisof

KlebsiellapnPathogenesisof

ProteusmirabilisUrinarytractinfectionsProducelargeamountsureaseUreaintocarbondioxideandammoniaChangesrenalpHFacilitatesformationofstonesAlsotoxicforuroepitheliumPresenceofpilimaydecreasevirulenceBetterphagocytosisBIOL53360Pathogenesisof

ProteusmiraPreventionandControlDifficult,becauseenterobacteriaarenormalfloraPreventionPlagueEffectivevaccinesProphylacticuseoftetracyclineformedicalworkersincontactwithpneumonicplagueVaccinesforSalmonellatyphiBIOL53361PreventionandControlDifficulPreventionandControlTreatmentUseofantibioticsusceptibilitytestingE.coliandProteusnormallyrespondwelltoantibiotictreatmentBIOL53362PreventionandControlTreatmenLecture12Questions?Comments?Assignments...BIOL53363Lecture12Questions?BIOL53363EnterobacteriaceaeBIOL533Lecture12MedicalMicrobiologyBIOL53364EnterobacteriaceaeBIOL533MediEnterobacteriaceaeDiversityofspeciesEcologyFoundworldwideinsoil,water,vegetation,andmicrobialfloraofanimalsandhumansSomearealwaysassociatedwithdiseasee.g.,Shigella,Salmonella,YersiniapestisSomearenormalflorathatcanbecomeopportunisticpathogense.g.,E.coli,K.pneumoniae,P.mirabilisBIOL53365EnterobacteriaceaeDiversityofEnterobacteriaceaeEpidemiologyAnimalreservoir:mostSalmonellainfectionsHumancarrier:Salmonellatyphi,ShigellaEndogenousspreadinasusceptiblepatientCaninvolveallbodysites5%hospitalizedpatientsdevelopnosocomialinfections,primarilycausedbyEnterobacteriaceaesuchasEscherichiaSitesofinfectionBIOL53366EnterobacteriaceaeEpidemiologyMicrobialPhysiology

andStructureCellmorphologyModerate-sizedGram—rodsNon-spore-formingMotile(withperitrichousflagella)ornon-motilePhysiologyAllarefacultativeanaerobesSimplenutritionalrequirements:FermentglucoseReducenitratestonitritesBIOL53367MicrobialPhysiology

andStruDistinguishingCharacteristicsOxidase¯:Distinguishesamongotherfermentativeandnon-fermentativeGram—bacilliLactosefermentation(redcoloniesonMacConkeyagar)SeparateEscherichia,Klebsiella,Enterobacterfromotherlactose—EnterobacteriaceaeBIOL53368DistinguishingCharacteristicsDistinguishingCharacteristicsResistancetobilesaltsSeparateShigellaandSalmonellafromnormalflorainthisgroupEosinMethyleneBlue(EMB)Lactose,eosinY,methyleneblue;Lac+;growwithgreensheenBIOL53369DistinguishingCharacteristicsVirulenceFactorsAntigensSomatic“O”LPSMajorcellwallAg;heatstableSpecific“O”antigensassociatedwitheachgenus;however,crossreactionsarecommonSalmonellaandCitrobacterEscherichiaandShigellaBIOL53370VirulenceFactorsAntigensBIOLVirulenceFactorsCapsularKEitherproteinorpolysaccharideHeat-labileMayinterferewithdetectionof“O”RemovedbyboilingorganismsCapsularantigenofSalmonellatyphireferredtoasViantigenBIOL53371VirulenceFactorsCapsularKBIOVirulenceFactorsCapsularK,continuedSharedbydifferentgenerabothinsideandoutsideoffamilyCrossreactionsE.coliK1withN.meningitidisandHaemophilusmeningitidisK.pneumoniaewithS.pneunomiaeOrganismswithspecificantigenshavebeenassociatedwithincreasedvirulence (e.g.,E.coliK1withneonatalmeningitis)BIOL53372VirulenceFactorsCapsularK,cVirulenceFactorsFlagellaHHeat-labileproteinsCanbeabsentorundergoantigenicvariation(presentintwophases)SpecificHantigensassocatedwithdiseaseBIOL53373VirulenceFactorsFlagellaHBIOVirulenceFactorsGeneralroleinpathogenesisof“O,”“K,”and“H”antigensSpecificantigensassociatedwithmeningitis,gastroenteritis,andurinarytractinfectionsRolethatAg’splayinthesediseasesisnotclearSomecapsularAgarepoorimmunogensProtectagainstantibody-mediatedphagocytosisFlagellarAgprobablyplayaroleinadherenceBIOL53374VirulenceFactorsGeneralroleVirulenceFactorsPiliAttachmenttohostcellsBIOL53375VirulenceFactorsPiliBIOL5331PathogenesisofEscherichiaE.colipresentingastrointestinaltractinnormalfloraBacterialsepsis(multiplicationinblood)Primaryfocus-infectionofurinarytractorspreadfromgastrointestinaltractDeathcanoccurinimmunocompromisedpatientsandinfectionsresultingfromintestinalperforationBIOL53376PathogenesisofEscherichiaE.PathogenesisofEscherichiaNeonatalmeningitisE.coliandgroupBstreptococcimostcommon75%E.colipossessCapsularK1antigenColonizationofinfantswithE.coliatdeliveryiscommon;diseaseisnotBIOL53377PathogenesisofEscherichiaNeoPathogenesisofEscherichiaUrinarytractinfections (80%communityandmostnosocomial)OriginatefromgastrointestinaltractImportantvirulencefactorsResistancetoserum-killingProductionofhemolysinsPili-mediatedbinding(notdemonstratedinvivo)ProductionofslimelayerthatparticipatesincelladhesionBIOL53378PathogenesisofEscherichiaUriPathogenesisofEscherichiaGastroenteritis (countrieswithpoorhygiene)Enterotoxigenic(ETEC)Mediatedbyheat-labile(likecholera)andheat-stableexotoxins(activatesguanylatecyclaseandstimulatessecretionoffluid)Botharecodedfromplasmid-bornegenesWorld-wide:bothadultsandchildrenIncubation1-2days;persists3-4daysMildsymptoms,includingcramps,nausea,vomiting,waterydiahrreaBIOL53379PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteroinvasive(EIEC)InvadeanddestroycolonicepitheliumFeverandcrampswithbloodandleukocytesinstoolUncommon;oftenfood-borneEnteropathogenic(EPEC;childhooddiarrhea)OrganismadherestoenterocyteplasmamembraneandcausesdestructionofmicrovilliproducingwaterydiarrheaAdhesivenessmediatedbyplasmid-encodedpiliBIOL53380PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteropathogenic(continued)Infants<1yearaffectedEnterohemorrhagic(EHEC;hemorrhagiccolitis)Producescytotoxin(verotoxin)Severeabdominalpain,bloodydiarrhea,littleornofeverWarmmonthsofyear;affectschildren<5yearsBIOL53381PathogenesisofEscherichiaGasPathogenesisofEscherichiaGastroenteritis,continuedEnteroaggregative(EaggEC;waterydiarrhea)Infants<6monthsAIDSpatientsBIOL53382PathogenesisofEscherichiaGasPathogenesisofDifferentToxinsCholeraandETECColonizemucosalsurfacebytoxincoregulatedpilus(cholera;TcpA)orcolonizationfactorAg(Cfa;E.coli)CtxorLTbindstoreceptorandtakenupbyvesicles;transportedfrombasolateralmembranetoACcomplexBIOL53383PathogenesisofDifferentToxiPathogenesisofDifferentToxinsCholeraandETEC(continued)ADP-ribosylationyieldscAMP(cholera-like)ETEC(heatstable;ST)bindstomembrane-boundguanylatecyclasecomplexthatproducescGMPBothcAMPandc-GMPreduceNa+absorptioninviluscellsIncreaseCI—secretionincryptcells;yieldswaterydiarrheaBIOL53384PathogenesisofDifferentToxiPathogenesisofDifferentToxinsEPECAttachestosmallbowelbybundleformingpilus(BfpA)BindingyieldssignaltransductioneventsPhosphorylationofmajorepithelialproteinHp-90ActivationphospholipaseCIncreaseinositoltriPO4(IP3)andCaDamagetomicrovilliBIOL53385PathogenesisofDifferentToxiPathogenesisofDifferentToxinsEPEC(continued)Intiminmediatesintimiteassociation39kDaproteincausespolymerizationofactinandothercytoskeletalproteinsandrearrangementofcytoskeletalstructureFormcharacteristicEPECpedestal(attachingeffacinglesion)withintimatelyattachedorganism;notknownhowhostgetsdiarrhea)BIOL53386PathogenesisofDifferentToxiPathogenesisofDifferentToxinsInterestingly,E.coli0:157H:7haspedestalandShigatoxin(char.Shigella)BIOL53387PathogenesisofDifferentToxiPathogenesisofSalmonellaSourceofmostinfectionsIngestionofcontaminatedwater,foodPoultry,eggs,anddairyproductsSalmonellatyphispreadbyfoodorwater;contaminatedbyfood-handlersNeedtoingestlargenumberoforganisms(106-8)Byfecal-oralcontactinchildrenBIOL53388PathogenesisofSalmonellaSourPathogenesisofSalmonellaGastroenteritis(mostcommon)Symptoms6-48hoursafteringestionNausea,vomiting,non-bloodydiarrheaElevatedtemperature,abdominalcramps,musclecramps,headacheSymptomspersistfor2daystoaweekbeforeabatingAntibioticsarenormallynotemployedbecausecarrierstatecandevelopBIOL53389PathogenesisofSalmonellaGastPathogenesisofSalmonellaGastroenteritis(continued)Moreacid-sensitivethanShigellaInfectpatientswithdecreasedstomachacidLargeinoculumneededDecreasedby10-100XinthepresenceofbicarbonateBIOL53390PathogenesisofSalmonellaGastPathogenesisofSalmonellaSepticemia(pediatricandgeriatricpatients)10%patientscanget:osteomyelitis,endocarditis,orarthritisBIOL53391PathogenesisofSalmonellaSeptPathogenesisofSalmonellaEntericfever (S.typhi,typhoid;S.paratyphi,paratyphoid)ParatyphoidismilderSymptomsafter10-14dayincubationperiodGraduallyincreasingremittantfever