病原微生物学资料：第一次网络考试题目和答案

PAGE1.AGramstainhasbeenperformedonabacterialisolatetakenfromasheepbloodagarplate.Uponobservation,thecellsappeartoberedtopinkrods.TheorganismispresumptivelyidentifiedasCitrobacterkoseri(克氏柠檬酸杆菌).Themostlikelyreasonfortheredcolorofthecellsinthestainisthatthe(A)APeptidoglycan（肽聚糖）layerofthecellwallisrelativelythinBPeptidoglycanlayerofthecellwallisrelativelythickCOrganismsinthisgenushavealipopolysaccharideoutermembraneDOrganismsinthisgenushaveonlyacytoplasmicmembraneECapsule（荚膜）tendstocapturethesafraninfromtheGramstainreagent2.Themedicalimportanceofspores（芽胞）liesinthefactthat:(C)ATheyhavekeratin(角蛋白)-likecoats.BTheycontainbacterialDNA.CTheyareextremelyresistanttoheatandchemicals.DTheyareformedinadverseconditions.3.CASE:A13-year-oldgirlwasadmittedtoahealthcarefacilitywitha5-hourhistoryofdiarrhea(腹泻)andvomiting（呕吐）.Onpatientinterview,thephysiciansuspectedittobeaninfectionbycontaminatedfood.Thephysicianrecommendeddiagnosticteststobedoneforthepatient.MicroscopicexaminationofthestoolonGramstainingrevealedGramnegativebacilli.Themicrobiologistdiscoveredshort,slender（瘦长的）rodsduringmicroscopicexaminationandsuspectedtheorganismtobeEscherichiacoli.WhichamongthefollowingmediahelpsindifferentiatingE.colifromothergeneraofentericbacteria?（B）ASheepbloodagar(SBA)BEosinmethyleneblue(EMB)agarCChocolateagarplateDLiquidmedia4.ThetoxinofCorynebacteriumdiphtheriae（白喉棒状杆菌）isresponsibleforthevaccine-preventablechildhoodillnessdiphtheria（白喉）.Toxinproductioninthisorganismismediatedbychromosomalgenesthatoriginatedfromabacteriophage.WhenincorporatedintotheDNAofahostcell,bacteriophageDNAiscalledaprophage（原噬菌体）.Organismsthatcontaintheprophageproducethetoxinandcausediphtheria,whilethosethatdonotcontaintheprophageareprobablynonpathogenic.ThismechanismofDNAtransferfromonecelltoanotherbywayofabacteriophageiscalled（A）ATransduction（转导）BTransformation（转化）CConjugation（接合）DTransfection（转染）ERecombination（重组）5.A5-year-oldboyistakentoaphysicianafterhisinsectbitegetsinfected.Thedoctortakesaspecimenfromthelesionforcultureandacatalase（触酶）-positive,Gram-positivebacteriagrowinginclustersisisolated.Whatelseisafeatureofthisorganism?（E）ACanmakesporesBProducesgamma-hemolysisonbloodagarCCanonlygrowanaerobicallyDProducesapotentendotoxinECanfermentmannitol（甘露糖）andgrowonhighsalt6.A39-year-oldwomancomesintoyourofficebecauseshehashadseverediarrheaforthepast2days,accompaniedbyfeverandashakingchill.Sheusesantacids（抗酸药）.Otherwisesheishealthy.Astainforfecal（粪便）leukocytes（白细胞）revealsmanyPMNs（中性粒细胞）.Testforoccultblood（便隐血）waspositive.Fromthestoolcultureagram-negativerodwasisolatedthatdoesnotfermentlactose（乳糖）.Triplesugariron（TSI）agarshowsanalkalineslant,acidbutt,withbothgasandH2S.Theurease（尿素酶）testwasnegative.Whichoneofthefollowingorganismsisthemostlikelycause?（A）ASalmonellatyphimurium（鼠伤寒沙门氏菌）BEscherichiacoliCCampylobacterjejuni（空肠弯曲菌）DVibrioparahaemolyticus（副溶血弧菌）EVibriocholerae7.AmanbringshisuncletoyourofficeandtellsyouthattheunclelivesintheCaribbean（加勒比海）butisintheUnitedStatesonvacation.Hecomplainsofaverysorethroatandhasproblemsswallowing.Thelymphglands（淋巴腺体）inhisneckareveryswollen（肿大）.Yoususpectthathehasdiphtheria,whichisconfirmedbyathroatculture.Onedomainofthetoxinisinvolvedintheinhibitionofproteinsynthesis.Aseconddomainisinvolvedin（A）AtoxinbindingtothecellreceptorBinhibitingDNAreplicationCcleavageofthe28SribosomalRNADbindingandsequesteringelongationfactorsEtransportingtoxinintothenucleus8.Staphylococcalbacteriacauseawidevarietyofhumandisorders,fromfoodpoisoningtorashes（发疹）.Somestrainsofstaphylococcicausetoxicshocksyndrome(TSS),amultisystemdisease.ThecauseofTSSisatoxincalledtoxicshocksyndrometoxin1(TSST-1),originallyrecognizedasoneofthepyrogenic（化脓性）staphylococcalenterotoxins.Itisoneofagroupoftoxinsknownaswhat?（A）ASuperantigens（超抗原）BImmunotoxins（免疫毒素）CImmunophilins（亲免素）DToxoids（类毒素）ERTXtoxins（在细胞膜上打孔的外毒素）9.Anexperimentisdevisedtostudytheinvitroeffectsofcytokinesandotherchemokinesonmacrophages.Recombinantinterferonsalpha,beta,andgamma,interleukin-1,interleukin-2,interleukin-4,interleukin-6,granulocytemacrophagecolonystimulatingfactorandtumorgrowthfactorbetawereaddedindividuallytomacrophages.Whichofthefollowingcytokinesorchemokinesactivatemacrophagesbyamechanismthatinvolvesincreasedionexchange?（F）AInterferon-alpha,interferon-beta,andinterferon-gammaBInterleukin-1CGranulocytemacrophagecolonystimulatingfactorDTumorgrowthfactor-betaEInterferon-betaFinterferon-gammaGinterleukin-2Hinterleukin-4Iinterleukin-610.A36-year-oldAmericanIndianisadmittedtotheisolationunitatyourhospitalfortreatmentofpulmonarytuberculosis,whichwasdetectedataroutinecheckupthedaybefore.Heworksataconstructionsite（建筑工地）downtown（市中心）andhasnotbeenincontactwithanyfarmanimals.Besidestreatment,youneedtoinformhimofthemostcommonwayoftransmittingthedisease.Whichcontaminationisusuallyresponsible?(E)ABloodcontactBHandsCEatingutensils（餐具）DMilkproductsEDropletnuclei（飞沫核）11.Anelderlywomanwasadmittedtothehospitalforasepticwoundtreatmentonherlowerabdomenwhichdevelopedafteracolonoperation.Herwoundwas1.5-cmopen,andoozing（渗出）ayellowexudate（分泌液）.Whichisthebestwayofsterilizing（消毒）thesheetofthebed（床单）contaminatedwiththesepticwound'ssecretion?（D）AUsinganionicagentsolvents（阴离子溶剂）BUsingnonionicagentsolvents（非离子型表面活性剂的溶剂）CDryheatsterilization（干热灭菌）DAutoclavesterilization（湿热灭菌）ERadiation（辐射）12.A30-year-oldmancomesintoyourofficebecauseofdiarrhea（腹泻）thatbeganontheairplanewhilehewasreturningfromavacationintheMiddleEast.Hehadmultipleepisodesofwatery,non-bloodydiarrheaandlittlevomiting.BP130/85mmHg,P76,T36,8°C.Youmakeastainforfecalleukocytes,whichrevealsnoPMNs.Testforoccultbloodisnegative.Cultureofthestoolrevealspigmented（有颜色的）coloniesoneosin-methyleneblue(EMB)agar.Whichoneofthefollowingorganismsisthemostlikelycause?（A）AEscherichiacoli(enterotoxigenicstrains)BEscherichiacoli(enteropathogenicstrains)CEscherichiacoliO157:H7DS.typhimuriumES.dysenteriae13.WhichofthefollowinggroupofEscherichiacoliisthecommoncauseofdiarrheaininfantsandisimplicatedinoutbreaksofdiarrheainnurseries?（C）AEnterotoxigenicBEnteroinvasiveCEnteropathogenicDEnterohemorrhagicEEnteroaggregative14.ThemajorpropertythatdistinguishesE.colifromthetwootherintestinalpathogensShigellaandSalmonellaisthatitferments（A）ALactoseBMaltoseCFructoseDGlucoseEAcetate15．A45-year-oldwomancomesintoyourofficewitha2-dayhistoryofabdominalcrampsandbloodydiarrhea.ShehasjustreturnedfromhervacationinIndia,wheresheatemanyofthelocalfoods.Herbloodpressureis120/80mmHg,pulserateis84/minute,andtemperatureis37.8°C.StoolexaminationrevealsmanypolymorphonuclearleukocytesandaerobicGramnegativenon-motileorganisms.Fromthestoolculture,aGram-negativerodwasisolatedthatformscolorlesscoloniesoneosin-methyleneblue(EMB)agar.Whatorganismisthemostlikelycause?（A）AShigelladysenteriaeBEscherichiacoliCVibriocholeraeDVibrioparahaemolyticusEYersiniaenterolitica（黑死病致病菌耶尔森菌）16.Whichofthefollowinggram-negativerodsarefoundinseawaterandarethecommoncauseoftoxigenicwater-lossdiarrhea?Thesebacteriaarehighlymotilewithasinglepolarflagella.（A）AVibriocholerae（霍乱弧菌）BProteusmirabilis（奇异变形杆菌）CShigellaflexneri（弗氏志贺菌）DEscherichiacoli17.6hoursaftereatingrawfishandotherseafoodataJapaneserestaurant,acoupledevelopednauseaandvomiting,waterydiarrhea,abdominalcramps,andfever.Whatorganismislikelyinvolvedinthepatients’condition?（E）ASalmonellaenteritidis（肠炎沙门氏菌）BBacilluscereus（蜡样芽胞杆菌）CClostridiumperfringens（产气芽胞梭菌）DStaphylococcusaureusEVibrioparahaemolyticus（副溶血弧菌）18.TheantibioticrecommendedbyCentersforDiseaseControl(CDC)fortreatmentofgonorrheais（B）APenicillinBCeftriaxone（头孢曲松）CErythromycin（红霉素）DTetracycline（四环素）EAminoglycosides（氨基糖甙类）19.BiologicactionsofProteinIassociatedwithgonococciinclude（B）AAntiphagocyticactionsBFormationofsurfaceporesCAttachmenttohumancellslikeepitheliumofvaginaDHydrolysisofβ-lactamringinpenicillinEIronbinding20.Asexuallyactive18-year-oldmanattendsagenitourinarymedicineclinic（泌尿生殖医药门诊）withacomplaintofpainfulurethraldischarge（尿道排出物）.Afterappropriatestudies,adiagnosisofgonorrhea（淋病）ismade.Whichofthefollowingwouldmostlikelybefoundonasmearofhisdischarge?（D）AGram-positiverodsBGram-negativerodsCGram-positivecocciDGram-negativecocciEAcid-fastbacilli（抗酸细菌）21.Gramnegativediplococcialongwithlargenumberofpolymorphonuclearneutrophilswereseeninthecerebrospinalfluidofa21yroldmalehavingsymptomsofpurulentmeningitis.Thecoloniesonchocolateagarwerecatalasepositiveandoxidasepositive.Theisolateproducedacidfromglucoseandmaltose（麦芽糖）butnotfromsucrose（蔗糖）andlactose.Thecausativeorganismis（C）AStreptococcuspneumoniae（肺炎链球菌）BStreptococcusagalactiae（无乳链球菌）CNeisseriameningitidisDNeisseriagonorrhoeaeEEscherichiacoli22.Speciesofspore-formingbacteriabelongingtotheClostridiumgenusincludeseveralpathogensofmedicalimportance.Whichofthefollowingisthemostlife-threateningcharacteristicofsuchbacteria?（C）ALackofprophylacticvaccinesBFeverproductionCProductionofexotoxinsDInvasivepotentialEFormationofendospores23.Thetetanospasmin（破伤风痉挛毒素）（C）AisapotentendotoxinBisaheatstableproteinCcausescontinuousexcitationofmotorneuronsDAandCEBandC24.A10-year-oldboyisbroughttotheemergencyroombyhismother.Hehasa4-dayhistoryofmalaise,sorethroat,anorexia,andlow-gradefever.OnPE,pharyngealinflammationandagreypseudomembranecoveringthetonsilsarevisualized,whichbleedsontryingtoremoveit.Cultureshowsblackcoloniesandsmearshowsclub-shapedgrampositiverods.Howdoesthetoxinproducedbythisbacteriaact?（D）AItdecreasesglycineandgammaaminobutyricacidbyproteincleavageBItincreasescAMPbyADPribosylationofGi-alfaproteinCItincreasescAMPbyADPribosylationoftheGs-alfaproteinDItinhibitstheproteinsynthesisbyaddingADP-ribosetotheelongationfactor2EItstimulatesadenylatecyclasebyADPribosylationofGTPbindingprotein25.Whichofthefollowinganaerobeisassociatedwithproductionofdoublezoneofhemolysis?（A）AClostridiumperfringensBClostridiumdifficileCClostridiumsepticumDClostridiumtetaniEClostridiumsordellii26.Diphtheriatoxinactsby（A）AInhibitingproteinsynthesisBBlockingmRNAbindingCProducingedema（水肿）DIncreasingtranslation27.DPTvaccinecontains（A）AToxoidfordiphtheriaandtetanusandheatkilledorganismsforwhoopingcoughBToxoidfortetanusandheatkilledorganismsfordiphtheriaandwhoopingcoughCToxoidforwhoopingcoughandtetanusandheatkilledorganismsfordiphtheriaDToxoidfordiphtheria,tetanusandwhoopingcoughEHeatkilledorganismsfordiphtheria,tetanusandwhoopingcough28.Corynebacteria（棒状菌）are（B）AMotileBCatalasepositiveCSporeformersDDonotfermentcarbohydratesEStrictanaerobes29.Corynebacteriaare（C）ASmall,pleomorphicgram-negativebacilliBMotileCNon-sporeformersDDevoidofmycolicacid（无分枝菌酸）EStrictanaerobes30.Amantadine（金钢胺）,usedfortheprophylaxisofinfluenza,functionsbywhichofthefollowingmechanisms（E）AInhibitionofviraltranscriptionBInhibitionofviraltranslationCNeutralizationofextracellularviralparticlesDInhibitionofthereleaseofviralparticlesEInhibitionofpenetrationofthecellmembraneofthetargetcell31.Theseenveloped,pleomorphic（多形性）,andss-RNAvirusescauserespiratoryinfectionsbydropletnucleiorcontacttransmission.Thesebelongtotheorthomyxovirusgroupandarecalledwhat?（B）ALentivirusesBInfluenzavirusCParainfluenzavirusDRespiratorysyncytialvirus32.Whichofthefollowingarestructurallymostcloselyrelatedtotheinfluenzavirus?（C）ARetroviridaeBTogaviridaeCParamyxovirusesDCoronaviridaeERhabdoviridae33.Whichofthefollowingarestructurallymostcloselyrelatedtotheinfluenzavirus?（C）ARetroviridaeBTogaviridaeCParamyxovirusesDCoronaviridaeERhabdoviridae34.Althoughtheusualwayinwhichaparticleentersacellisbyphagocytosissothattheparticleisenclosedinaphagocyticvacuole,thereareothermethodsofentry.Ifvirusesentercellsbyphagocytosis,theyaredestroyedbyhydrolyticenzymes.Howdomostnonenvelopedandenvelopedvirusesentercells?（A）AEndocytosisBOpsonizationCNeutralizationDPhagocytosisEPinocytosis35.Aninvitroexperimentisdesignedtoexaminethesequentialstepsinvolvedinviralinfectionandreplication.Givenhealthyviablecellsandvirus,whichofthefollowingaccuratelydescribesthecorrectsequenceofstepsinviralinfectionandreplication?（C）Auncoating,attachment,biosynthesis,penetrationBattachment,uncoating,penetration,biosynthesisCattachment,penetration,uncoating,biosynthesisDuncoating,attachment,penetration,biosynthesisEuncoating,penetration,attachment,biosynthesis36.Youarestudyingavirusisolatedinthelaboratoryfrommouseepithelialcells.Thegeneticmaterialfromthisvirusisexaminedandfoundtocontainadenine,guanine,cytosine,anduracil,butnothymine.Youbegintostudythemechanismofreplicationofthisvirus.Basedonthefactthatthegeneticmaterialofthisviruscontainsuracil,whatistheenzymeuniquetothesetypesofvirusesthathelpsformdouble-strandedDNA?（C）AGuanylatecyclaseBIntegraseCReversetranscriptaseDTopoisomeraseEDNAligase37.Abasicscientistatamedicalschoolisinterestedinevaluatingamouseforexposuretoavirus.Severalsamplesoftissuesandcellsaretakenforanalysis.Whichofthefollowingmethodsforassessingviralexposureisbasedonanindirectmeasurement?（B）ADetectionofviralDNAorRNAincells,serum,ortissuesBDetectionofantiviralantibodiesinthebloodortissuesCDetectionofintracellularviralantigensDDetectionofvirusparticlesEVisualizationofvirionsbyelectronmicroscopy38.Althoughprimarytuberculosisisofthegreatestconcerntomostphysicians,somepatientswhohavebeenpreviouslyinfectedwithMycobacteriumtuberculosismayexperiencesecondaryorreactivationdisease.Themostlikelyexplanationforthereactivationofthisdiseaseinpatientsis（D）AThereisalocalactivationofthehumoralimmuneresponseandaconcomitantactivationofthecomplementsystemthatinitiatesthebreakdownofolder,calcifiedlesionsinthelung,leadingtothereappearanceofsymptomsBBecauseofthecontinuedexposureoftheetiologicagenttolongtermtherapywithmultipleantituberculosisdrugs,secondarydiseaseemergeswhenantibioticresistantstrainsofM.TuberculosisreachacriticalmassinadormantlesionandthenbreakthroughtoreinitiatesymptomsCTheinfluenceofpulmonarydiseaseotherthantuberculosis,suchasbacterialpneumonia,promotesaB-cellresponsethatinitiatesthebreakdownofthecalcifiedlesionsinthelungDTherecrudescenceofdormantfocifromtheprimaryinfectionisassociatedwithalocalbreakdownofthecellularimmunesystembyfactorssuchasage,diabetesmellitus,orobstructivepulmonarydisease.Becauseofthehostshypersensitivitytothetuberculoprotein,thelocalizedlesionbecomesnecroticandundergoesliquefactionEThedormant（休眠的）focithroughoutthelungsundergoanaturalagingprocesswherebychangesintheultrastructureofthecalcifiedlesioninitiatea"leakage"oforganisms.Generally,therecrudescenceisnotinfluencedbytheimmunestatusofthehost39.Mycobacteriumtuberculosis（C）AIsacidfastduetoverylowlipidcontentofcellwallBIsanobligateanaerobeCHascordfactorandsulfatideproduct,whichcontributestovirulenceDCannotsurviveinsidenormalmacrophageEProducesendotoxins40.A7-montholdchildpresentstotheemergencyroomexhibitingtoxicepidermalnecrolysisandlarge,flaccidbullaethatareformingandrupturingundertheepidermis,causingdesquamationinthediaperarea.Thisspectrumofdiseasedescribesaconditionusuallycausedby:（A）AToxinproducingStaphylococcusaureus.BInvasiveEscherichiacoli.CProphageinfectedCorynebacteriumdiphtheriae.DFlesh-eatingStreptococcuspyogenes.EDermalinfectionwithClostridiumperfringens.41.A32-year-oldwomanisbroughttotheemergencyroomwithsuddenonsetoffever,headache,sorethroat,profusewaterydiarrhea,vomiting,andlethargy,whichstartedinthemorning.Onphysicalexamination,sheisslightlyconfused,hertemperatureis39°C(103°F),herbloodpressureis100/50mmHgandshehasdiffusesunburnlikeaerythematousrash.Whentheemergencydoctoristryingtofindoutifsheispregnant,shementionsthatherperiodstarted2daysago.Whichofthefollowingisthemostlikelydiagnosis?(D)AScarletfever（猩红热）BRockyMountainspottedfeverCMeningococcemiaDToxicshocksyndromeEFoodpoisoning42.CASE:A38-year-oldmanwasadmittedtoahealthcarefacilitywithnausea,vomiting,diarrhea,andabdominalcrampingforthepast2hours.HisBPwas100/60mmHg.Oninterviewingthepatient,herevealedthathehadconsumedmeatthathadbeenleftuncoveredforanight.Thephysiciansuspecteditasacaseoffoodpoisoning.Duringlaboratoryexaminationitwasfoundthatthemeatwascontaminatedwithcircular,clusteredorganisms,whichonGramstainingwerefoundtobeGrampositive.Fairlylarge,yellowcoloredcolonieswereformedwhentheorganismwasgrownonmannitolagarmediainatemperaturerangeof15to45°C.Theorganismshowedpositiveresultsforcoagulaseenzymeactivityandshowedresistancetopenicillinandmethicillinantibiotics.

Whatorganismwasthecausativeagentofthefoodpoisoning?(D)AClostridiumperfringensBEnterococcusfecalisCEscherichiacoliDStaphylococcusaureusESalmonellaspecies43.CASE:Apreviouslyhealthy24-year-oldwomanpresentedwithhighfeverofsuddenonset,severemyalgia（肌肉疼痛）,headache,vomiting,diarrhea,anddiffusescarlatini-formrashresemblingsunburns.Shewasonthefourthdayofhermensesandwasusingtampons（卫生棉塞）.Herbloodpressurewasnotedas70/40mmmercury.Aspartoflaboratoryinvestigations,blood,urine,andvaginalculturesweredone.Accordingtothemicrobiologyreport,heavygrowthofstaphylococcusaureuswasobtainedfromvaginalculture.Preliminaryreportofherbloodcultureshowednogrowthafter24hrsincubation.Microscopyofurinesedimentshowed15leucocytesperhighpowerfield.Urineculturedidnotyieldanysignificantgrowth.Whichofthefollowingstaphylococcaltoxins