《细菌学名》PPT课件.ppt

細菌學名 疾病 症狀 如何造成疾病 致病機制 治療 預防 診斷 型態生長特性生化反應血清學反應 細菌本身 侵襲性 毒力因素 產毒力 毒素 宿主因素 抵抗力 易感因素 如何感染 途徑 媒介 抗生素 抗藥性 抗毒素 症狀治療 環境及個人衛生 疫苗 A菌 B菌 Name Binomialnomenclature Diseases Symptoms Pathogenesismechanism Treatment Prevention Diagnosis MorphologyGrowthpropertiesBiochemicalreactionsSerologicaltests Bacterialvirulencefactors invasiveness toxins Hostfactors defensemechanism predisposingfactors Routeofinfection Vectors Antibiotics drugresistance Antitoxins Supportivetherapy Sanitation Vaccination BacteriumA BacteriumB PyogenicCocci Staphylococcusgram positive Streptococcusgram positive Neisseriagram negative Stapylococcusandrelatedorganisms S aureus majorpathogenforhumans maycausesuppuration abscessformation scaldedskinsyndrome toxicshocksyndromeandfoodpoisoning S epidermidis maycauseinfectionfromprostheticdevices S saprophyticus maycauseurinarytractinfections UTI inyoungwomen S capitis endocarditis UTI andopportunisticinfections S haemolyticus endocarditis UTI andopportunisticinfections Micrococcusspp opportunisticinfections Stomatococcusmucilaginosa endocarditis opportunisticinfections Alloiococcusotitidis chronicmiddleearinfection StaphylococciNonmotile spores Growreadilyonmostbacteriologicalmedia facultativeanaerobic Growmostrapidlyat37oC butformcarotenoidpigmentbestatroomtemperatureunderaerobicconditiononsolidmedium Producecatalase Relativelyresistanttodrying heat 40oC and10 NaCl Gram positivecocci abunchofgrapes MorphologyandIdentification Structureofstaphylococcalcellwall CapsuleNotreadilyseeninvitroAtleast11typesinS aureusInhibitingphagocytosisbypolymorphonucleocytes SlimelayerLoose bound water solublefilmFacilitatesbacterialadherencetotissuesorforeignbodiesand consequently biofilmformation importantforthepathogenesisofcoagulase negativestaphylococci PeptidoglycanHasendotoxin likeactivityinducesproductionofcytokinesactivatescomplementinducesaggregationofpolymorphonucleocytes TeichoicacidsandlipoteichoicacidsBindcovalentlytopeptidoglycan species specific bindtofibronectinofhostcells adherence antibodiesmaybefoundinsystemicstaphylococcaldisease particularlyendocarditis ProteinA presentonthesurfaceofS aureusstrains butnototherspecies BindstotheFcportionofIgGexceptIgG3 preventingclearanceofbacteria Coagulase clumpingfactor ProducedbymostS aureusonthecellwallsurface bindstofibrinogenandconvertsittofibrin resultinginaggregatesofbacteria Otheradhesinsbindwithcollagen elastinandfibronectin Coagulase positivevs coagulase negativestaphylococci Cytotoxinsa toxin pore forming cytotoxictomanytypesofcellsincludingmusclecells b toxin degradessphingomyelinandistoxicformanykindsofcells includinghumanRBCs g toxin bicomponenttoxins pore forming d toxin hasdetergent likeactivity P Vleukocidin similartog toxininstructure killsWBCsofmanyanimalsandreleasethelysosomalenzymes Associatedwithseverepulmonaryandcutaneousinfections PathogenesisandImmunityS aureuscanproducediseasesboththroughinvasivenessandproductionoftoxins Toxins Exfoliative epidermolytic toxins proteasesthatsplitdesmoglein1oftheintercellularbridgesinepidermis producedbyabout5 10 ofS aureus causesthegeneralizeddesquamationofthestaphylococcalscaldedskinsyndrome SSSS Toxicshocksyndrometoxin 1 TSST 1 superantigen associateswithfever shock desquamativeskinrashoftoxicshocksyndromeinhumans Enterotoxins superantigens atleast10 A B C1 C2 C3 D E G H andI solubletoxinsproducedbyabout50 ofS aureus Heat stable 100oC 30min andresistanttothegastricacidandgutenzymes Enterotoxinsareproducedincarbohydrateandproteinfoods Causingemesis acharacteristicofstaphylococcalfoodpoisoning Toxins continued Enzymes Coagulase boundandfreeforms Maydepositfibrinonthesurfaceofstaphylococciandaltertheiringestionbyanddestructionwithinthephagocyticcells associatedwithinvasiveness Fibrinolysin staphylokinase todissolvefibrinclot Catalase toremoveH2O2 Hyaluronidase tofacilitatespreadofS aureusintissue Lipase associatedwithsuperficialskininfection Nuclease producedonlybyS aureus Penicillinase Staphylococcicanpermanently coagulase negativestrains ortransiently S aureus colonizevariousareasofthehumanbody withtheanteriornasopharynxasthemostcommoncolonizationsiteforS aureusinolderchildrenandadults 30 ofhealthyadults NasopharyngealorskincarriersofS aureusareresponsibleformanyhospitalinfections S aureuscanbetransmittedthroughdirectpersonalcontactorcontactwithcontaminatedfomites Areasathighestriskforsevereinfections newbornnursery ICU operatingroomsandcancerchemotherapywards Epidemiology ClinicalDiseases Cutaneousinfections folliculitis e g styeandacne furuncles carbuncles impetigo usuallyanintense localizedpainfulinflammatoryreactionthatundergoescentralsuppurationandhealsquicklywhenthepusisdrained Carbunclepatientsfrequentlyhavesystemicsigns S aureus Woundinfections canoccuraftersurgeryortrauma mayinvolveskin bone osteomyelitisfromanopenfracture ormeninges meningitisfromskullfracture BacteremiaMostlyresultsfromsurgeryorcontinueduseofintravascularcatheters Bacteriamayspreadtootherbodysitesandcauseendocarditis hematogenousosteomyelitisandsepticarthritis meningitis andpulmonaryinfection hematogenouspneumonia andempyema ClinicalDiseases Septicembolism S aureus continued AspirationpneumoniacausedbyS aureusisseeninveryyoung veryold cysticfibrosispatients influenza etc Staphylococcalscaldedskinsyndrome SSSSorRitterdisease forminglargebullaeorcutaneousblisterswithclearfluidthatcontainsnobacteriaorleukocytes Spreadsrapidly Occursmuchmoreoftentoneonatesandyoungchildren ClinicalDiseases S aureus continued BullousimpetigoisalocalizedformofSSSS UnlikethedisseminatedSSSS theblisterscontainthebacteria Highlycommunicable Foodpoisoning causedbyingestionofpreformedenterotoxininfood meatandcarbohydrates Shortincubation 1 8hr Violentnausea vomitingandwaterydiarrhea nofever rapidconvalescence Staphylococcalenterocolitisoccursinpatientswhohavereceivedbroadspectrumantibiotics antibiotic associateddiarrhea ClinicalDiseases Toxicshocksyndrome abruptonsetofhighfever vomiting diarrhea myalgia scarlatiniformrash desquamationofpalmsandsoles andhypotensionwithcardiacandrenalfailure Thisdiseasehasoccurredinchildreninjectedwithcontaminatedvaccine 1928 andyoungwomenwhousedtampons 1980 Thismayalsooccurinchildrenorinmenwithstaphylococcalwoundinfections halfcasesarecausedbyenterotoxinBand rarely enterotoxinC ClinicalDiseases S epidermidisandothercoagulase negativestaphylococci Endocarditis causedbyinfectionofnative rarely orprostheticheartvalves Catheterandshuntinfections amajormedicalproblem becausecathetersandshuntsarecommonlyusedincriticallyillpatients Slimeproductionthatcausesbiofilmformationpreventsthebacteriafromantibioticsandinflammatorycells Persistentbacteremiaisgenerallyobserved Prostheticjointinfections localizedpainandfailureoftheartificialjoint Systemicsignsarenotprominent Reinfectionofnewjointisincreasedinsuchpatients Urinarytractinfections UTIinfectionbyS saprophyticusoccursmostlytoyoung sexuallyactivewomen LaboratoryDiagnosis Specimen pus sputum blood anteriornasalandperinealswabs left overfoodetc Smear exceptforabscessmaterial gramstainofthesmearisusuallynotinformative Serology antibodiesagainstteichoicacidcanbedetectedinpatientswithstaphylococcalendocarditis butnotthosewithosteomyelitisorwoundinfection Elevatedantibodytitersisanindicationforprolongedantibiotictreatment LaboratoryDiagnosis Culture bloodagarplates Use7 5 NaCltoinhibitcontaminants Mannitol saltagarcanbeusedasaselectivemediumforS aureus Hemolysisandpigmentproductionmaynotoccuruntilseveraldayslaterandareoptimalatroomtemperature Identification catalasetest coagulasetest Fluorescentinsituhybridization FISH withaS aureus specificDNAprobecanbeusedforidentificationofthisorganisminclinicalspecimens Varioussubtypingmethods suchaspulsed fieldgelelectrophoresis areusedforepidemiologicalpurpose DrugresistanceofS aureusTetracyclineareusedforlongtermtreatmentofacneorfurunculosis Abscessandotherclosedsuppurationlesionsaretreatedbydrainageandantibiotics Bacteremia endocarditis pneumoniaandotherseverestaphylococcalinfections prolongedi v therapywithb lactamase resistantpenicillins e g methicillin oxacillin etc Vancomycinisthemosteffectivedrugagainststaphylococci butitsuseisrestrictedinmosthospitals Treatment DrugresistanceofS aureus1 ResistancetopenicillinG ampicillin andsimilardrugsiscommon 2 Resistancetonafcillin methicillinandoxacillinMRSA ORSA methicillin oxacillin multiresistantS aureus resultingfromacquisitionofmecA whichencodesanovelPBP PBP2 thatisnotboundbyb lactams MRSAstrainsareusuallyalsoresistanttotetracyclines erythromycinsandaminoglycosides Remainsusceptibletovancomycin However manystrainshavebecomemoderatelyresistanttovancomycin calledvancomycin intermediateSA VISA and notably twovancomycin resistantstrains VRSA havebeenisolatedinUSAsince2002 Staphyloxanthin thecarotenoidpigment actsasananti oxidantandhelpsthebacteriaresistkillingbythereactiveoxygenspecies ROS suchasO2 H2O2andHOCl inneutrophils Bacteriathatlackthispigmentgrownormally butaredeficientinskinabscessformation Newchem