病原生物學英文版課件：Other Gram Postive

Non-spore-formingGram-positiveBacteria---Corynebacterium,Listeria,ActinomycetesandNocardiaGrampositiverodsSporeformingNonsporeformingAnaerobicAerobicClostridiumsppBacillussppCorynebacteriumGramPositiveBacilliCorynebacteriumdiphtheriae

BiologicalFeatures

Aerobic,Gram+,Noncapsulated,rodsGray-blackcoloniesontelluritemedium(亞碲酸鉀血平板)Metachromaticgranules(異染顆粒)Chinese-lettermorphologyinGramstainTransmissionandRiskfactorssolelyamonghumansspreadbydropletssecretionsdirectcontactPoornutritionCrowdedorunsanitarylivingconditionsLowvaccinecoverageamonginfantsandchildrenImmunitygapsinadultsPathogenesisofdiphtheriaEarlystages:

Sorethroat.Lowfever.Swollenneckglands.Latestages:

Airwayobstructionandbreathingdifficulty.ShockDiphtheriaToxin(DT)CleavedtoyieldA/Bfragment,joinedbyS-Sbond

-A(catalyticdomain)-B(transmembraneandreceptorbindingdomains)Receptor:heparin-bindingepidermalgrowthfactorToxindiffusesthroughoutbodyviablood

-Cardiac,neurologiccomplications

-Heart/respiratorydamage,paralysis

Abruptarrestofproteinsynthesis!NecrotizingandneurotoxiceffectsImmunityImmunizationofanimalswithalteredtoxin,producingantitoxin,wasfirstdonein1890,1stusedinhumansin1891Toxoid(withimmunogenicity)introducedin1923,nowwidelyusedDIAGNOSISClinical:Muscleweakness,edemaandapseudomembranousmaterialintheupperrespiratorytractcharacterizesdiphtheria.Laboratory:TelluritemediaistheagarofchoiceforisolationofCorynebacteria,whichproducejetblackcoloniesElek’sTestfortoxigenicityPrinciple:Itistoxin/antitoxinreactionToxinproductionbyC.diphtheriaecanbedemonstratedbyaprecipitationbetweenexotoxinanddiphtheriaantitoxinProcedure:AstripoffilterpaperimpregnatedwithdiphtheriaantitoxinisplacedonthesurfaceofserumagarTheorganismisstreakedatrightangelstothefilterpaperIncubatetheplateat37Cfor24hrsResuls: After48hrsincubation,theantitoxindiffusingfromfilterpaperstripandthetoxigenicstrainsproduceexotoxin,whichdiffusesandresultedinfourprecipitationlinesradiatingfromintersectionofthestripandthegrowthoforganismFilterpapersaturatedwithdiphtheriaantitoxinInoculatedorganismPositiveElek’sTestLinesofprecipitationsControlSanitary:Reducecarrierratebyuseofvaccine.Immunological:Avaccine(DPT)preparedfromanalkalineformaldehydeinactivatedtoxin(i.e.toxoid)isrequired.Passiveimmunizationwithantitoxincanbeusedforpatients.Chemotherapeutic:Penicillin,erythromycinorgentamicinaredrugsofchoice.Actinomyces

A.israelii,A.naeslundii;Grampositive;sulfurgranule;RelatedtodecaytoothandperidentitisACTINOMYCESAnaerobic,filamentous,grampositivebacillusExhibittruebranching“Mykes”–Greekfor“fungus”Thoughtbyearlymicrobiologisttobefungibecauseof:MorphologyDiseasetheycauseClinicalspecimens:Actinomycosis-pusACTINOMYCOSISNothighlyvirulent(Opportunist)ComponentofOralFloraPeriodontalpocketsDentalplaqueTonsilarcryptsTakeadvantageofinjurytopenetratemucosalbarriersCoincidentinfectionTraumaSurgeryActinomycosisAchronicsuppurativeandgranulomatousdiseaseofthefacial,thoracicorabdominalareasACTINOMYCOSISForminduratedmasseswithfibrouswallsandcentralloculationswithpusPuscontains"SulfurGranules"Gritty,yellowwhiteAveragediameter-2mmComposedofmineralized“mycelial”mass

ChronicinfectionFormburrowingsinustractstoskinormucusmembranesDischargepurulentmaterialActinomycosis-sulfurgranulePulmonaryActinomycosis15%ofcasesAspirationoforganismfromtheoropharynxSlowlyprogressiveprocessinvolvinglungandpleuraMaybemistakenformalignancyChestpain,fever,weightlossandhemoptysisNocardiosisOpportunisticinfectionSubcutaneousinfections,pulmonaryinfections,andbrainabscesses

N.asteroides;N.brasiliensisLabDiagnosis/TreatmentClinicalSpecimens:Sputum,Pus,Biopsytissue,GramstainTherapy:Sulfamethoxazole-TrimethoprimListeriamonocytogenesGram-positivebeta-hemolyticbacillusMultiplyatrefrigeratortemperatures(4oC)TumblingmotilityatroomtemperatureIntestinaltractofmammals&birds(especiallychickens)PersistsinsoilSoftcheeses&unwashedrawvegetablesRaworundercookedfoodofanimaloriginLuncheonmeatsHotdogsLargescalefoodrecallshavebecomecommonLocationofListeriaEpidemiologyofListeriosisNaturalReservoirsCommonRoutesforHumanExposurePopulationatGreatestRiskEpidemiologyofListeriaInfectionsNeonates,elderly&immunocompromisedGranulomatosisinfantisepticaTransmittedtofetustransplacentallyEarlysepticemicform:1-5dayspost-partumDelayedmeningiticform:10-20daysfollowingbirthIntracellularpathogenCell-mediatedandhumoralimmunitydevelopOnlycell-mediatedimmunityisprotectiveListeriosis