fungi - respiratory 1

7/30/2019 Fungi - Respiratory 1

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FungiAssociatedwithRespiratoryTractInfections1

NotesfromTheSeahorse

ENDEMICRESPIRATORYMYCOSES

Acquiredfrom Portalofentry PrimaryfocusofInfection Agents

InhalationofCONIDIAfromsoil

Conidia

-Asexualspores

- Notencloseinsac/sporangium

Respiratorytract

- Inhalationofconidia

Noevidenceoftransmissionfromanimalstohumanorhumantohuman

Lungs

HaverestrictedgeographicdistributionExhibitTHERMALDIMORPHISM

- Existasmold/myceliainenvironment

- Yeastintissues/bodyCaninfecthealthyindividuals

I.Histoplasmosis

Characteristics Distribution Primarysourcesofinfection Occursas Causedby

-AKADarlings/Cavers/Spelunkersdisease,NorthAmerican

Histoplasmosis

FirstdescribedbySamuelDarling

Spelunker

- Apersonwhosehobbyisexplorationandstudyofcaves

NorthAmericanHistoplasmosisin

contrasttoAfricanHistoplasmosishasa

differentetiologicagent(Histoplasma

duboicii)

-Globallydistributed

- Incidencevariesbutishighestin

theUnitedStates

o Soilo Bathabitatso AvianHabitats

Turkeys,chickens,crows,blackbirds,starlingare

associatedwiththeinfection

Canbecontractedbyoccupationalexposure

Spelunkers,batguano/droppingminers

A.Asymptomaticinfection

- 90-95%ofcases

B.Pulmonaryinfection

(acute/chronic)- 5-10%ofinfectedindividuals- Acuterespiratoryillnessor- Chronicformmimicstuberculosis

C.Disseminatedinfection

- Reticulo-Endothelialsysteminvolvement,mucocutaneous

infection

- FoundintracellularinREcells-Liverandspleenareaffected(hepatospleenomegaly)

- Onchestx-ray,itmimicspulmonarytuberculosis(Lobar

infiltrates)

D.PrimaryCutaneousInfection

- Veryrare- Cutaneousinfection

usuallyofseenin

disseminatedinfection

Histoplasmacapsulatum

- Misnomer,nocapsule- Ascomycete(ajellomyces

capsulatus)- Thermallydimorphic:

facultativeintracellular

- Growsinsoilcontaminatedwithbird/batexcreta(soilhas

highnitrogencontent)

InfectiousParticle:MICROCONIDIA

- hastobesmalltoreachthealveoli


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LaboratoryDiagnosis

HistopathSection CultureatRoomTemperature Cultureat37C IDofcultures Otherdiagnostictests

Specimen:

- bodyfluids- tissuebiopsies

- StainedwithGiemsa/GMS/PAS

- Small,roundtoovalintra-andextra-cellularyeastcells

-OnGiemsaorWrightsstainedsmear:palebluebody(fungal

cellwall)surroundsthedarker

blueprotoplasma;cytoplasma

retractsfromthewalls,giving

thefasleimpressionofa

capsule

DIAGNOSTICMETHODOFCHOICE

-moldisgrown

Colonies:- Fineseptate,hyphae,largetuberculatemacroconidia and

smallmicroconidia

- Growmold

Tuberculatemacroconidia

- DiagnosticofH.Capsulatum

- Cannotdistinguishthefunususingthe

microconidia

Microconidia

-infectiousparticle

**yeastisgrownhere

Colonies:

-Small,single-buddingyeastcells

- StructuresseenaretheTISSUEFORM

- Convertanddemonstratedimorphismtoconfirm

diagnosis

- CulturethefungusinBHI(Brainheartinfusion)

- Incubateat37C- Moldphasewillconvertoyeastfaceandwillseethe

buddingyeastcells

- Laboratoryhazard- Microconidiacaninfect

laboratoryworkers

- Needtosetupfungal/mycology

laboratorywithaBSC

(BiologicalSafety

Cabiney)workstation

- Exoantigentest- Nucleicacidprobe

*doneinlieuofmold-to-yeast

conversion

Skintest(histoplasmin)

- NodiagnosticvalueSerology(CFtest)

Complementfixationtest

- Veryhelpful- HighCFantibodylevels

meansapoorprognosis

AntigenDetection(RIA,enzyme

immunoassay)

RIA-radioimmunoassayinvolves

theseparationofaproteinfroma

mixtureusingthespecificityof

Ag-Abbindingandqunatation

usingradioactivity

TreatmentandPrevention

Treatment Prevention

Notrequiredformostcases-Mostcasesareasymptomaticandself-limiting

Itraconazole,ketoconazole,fluconazole(pulmonary);amphotericinB(systemicordisseminatedforms)

Surgicalresectionofpulmonarylesions

- Wearingofprotectiveclothingbeforeenteringinfectedlabs- Soildecontaminationwith3-5%formalin(whenfeasible)


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BLASTOMYCOSIS

Characteristics Occursas Causedby Infectiousparticle

AKANorthAmericanblastomycosis,ChicagoDisease,

GilchristsDisease

FirstdescribedbyThomasGilchrist

FoundinNorthAmerica,Africa,Asia

Outbreaksassociatedwithactivities

- Moistsoilenrichedwithorganicdebris,rottingwood- Prevalentwiththoselivingnearriversandstreams

Naturaldiseasecommonincatsanddogs

- Importantveterinaryproblem- Noanimal-humantransmission- Highprevalenceofcanineorfelineblastomycosisisa

goodindicatorthatfungusispresentinarea

OftenmisdiagnosedasTuberculosis

A.Asymptomaticinfection

- ~50%ofcases

B.Pulmonaryinfection(acute/chronic)

- Acutebronchopneumonialike- ChronicPTBlikeinchestxray;lungcavitationwithorwithoutlobarinfiltrates

C.Disseminatedinfection

- Skin,bonemostcommon- GUT,CNS,spleen,kidney

D.ChronicCutaneousInfections

- Indisseminativeforms- Verrucous/ulcerativelesions- Microabscessesareverycommonintheselesions

E.PrimaryCutaneousInfection

-rare

Blastomycesdermatitidis

-Ascomycete(Ajellomycesdermatitidis)

-Nameinparenthesis=sexualstate

-Thermallydimorphic-Inhabitsdecayingwoodandmaterials;probablysoilsaprophyte

-Veryrarelyculturedformsoilinendemicareas

Conidia

-nomicro-or

macro-conidia

LaboratoryDiagnosisKOH/histopathexams CultureatRoom

Temperature

Cultureat37C IDofcultures Otherdiagnostictests

Specimen:

- dependonmanifestations;skinscrapings,pusfromskinlesions,sputumsinpulmonarydiseaseorbiopsytissues

- - Showsthick-walledyeastcellswithsinglebroadbasedbud

- characteristicofBlastomycesdermatidisisthebudattachedtoparentcellbybroadbasew/cisdifferentfromotheryeastcells

w/careattachedbyanarrowbase

Pyriformconidiaborne

singleonseptatehyphae

-nocharacteristic

patternofconidiation

-Double-walledyeastcellswithsinglebroad-

basedbud

-Seeneveninvitro-Brainheartinfusion

-Exoantigenttest-Nucleicacidprobe**Bothdoneinlieuof

moldtoyeasttest

SkinTest(blastomycin)

-Nodiagnosticvalue

Serology(CF,

Immunodiffusion)

-Complementfixation-Tissueidentification

Immunofluorescence

Antigendetection(RIA)


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Treatment:

Pulmonary CutaneousManifestations Disseminated

Ketoconazole

Itraconazole

Flucanozole

Excision/correctivesurgery AmphotericinB

COCCIDIOIDOMYCOSIS

Characteristics OccursAs: Causedby Infectiousparticle Tissueform

AKAPosadasDisease,San

JoaquinVallefever,Desert

rheumatism

FirstdescribedbyAlejandro

Posadas

EndemicinWesternHemisphere

Highestepidemicity:Semi-arid

regionswithalkalinesoils

(Sonorandesert)

Outbreaksoccurfollowingdust

storms,earthquakes,evacuations

thatspreadtheinfectiousparticle

A.AsymptomaticInfections

- ~60%ofcases

B.PulmonaryInfections

- ~38-40%ofcases- Acuteorchronic- Acute:mild,chestpain,

cough

- Chronic:

C.DisseminatedInfection

-


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Laboratorydiagnosis:

Specimen:Sputum,pusfromskinlesions,aspirates,CSF,andskinbiopsy

KOH/HistopathExam CultureatRoomTemperature Cultureat37C IDofCulture OtherDiagnosticTests

-thickwalledspherulesfilled

withnonbuddingendospores

Hyphaebearingbarrel-shapedarthroconidiaseparatedbydysjunctorcells

Dysjunctorcells

- pointsofdisarticulation- Hyphaewithemptyspaces

NotroutinelydoneMoldtoyeastconversionverydifficult

Exoantigentest Nucleicacidprobe Demonstrationofspheruleproductioninanimals

Skintest(coccioidin/spherulin)

-Quiteusefulincoccidioidomycosis

Serology(CF,Immunodiffusion)

-Associatedwithhighcomplementfixationantibodytiter=Poorprognosis

Immunofluorescence

-toconfirmdiagnosis

Treatment Prevention

Acuterespiratorydisease

- Notnecessarytotreat

ForPulmonaryandDisseminatedDisease:

- Itraconazole- Ketoconazole- Fluconazole(formeningitis)- AmphotericinB(disseminated)

Surgery

Reduceexposuretodust(soil)inendemicareas

Vaccinedevelopmentinprogress

Brieftraveltoendemicareacanleadtoinfection Veryinfectious


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PARACOCCIDIOIDOMYCOSISCHARACTERISTICS OCCURSAS CAUSEDBY INFECTIOUSPARTICLE

AKASouthAmericanblastomycosis,

BrazilianBlastomycosis,LutzSplendore-

AlmeidasDisease

HigherincidenceinMALES(9-15:1)

- Myceliumtoyeastconversionsinhibitedbyestrogen

EndemicinCentralandSouthAmerica,

SouthernMexico

AsymptomaticInfection

Pulmonaryinfection

- Acuteflu-likeorpneumonialike- Chronicmimic

coccidioidomycosisorPTB

DisseminatedInfection

- Granulomatouslesionsinoralandnasalmucosa (mulberry

lesions)mostcommonand

characteristicof

paracoccidioidomycosis

- Cellwallpolysaccharide(alpha-glucan)stimulatesgranulomaformation

Paracoccidioidesbraziliensis

- Deuteromycete- Thermallydimorphic- Naturalhabitatisunknown- Foundtoresideinhumidsoilrich

inproteins

- Rarelyrecoveredfromendemicareas;hasbeencultivatedinfruit

batsandarmadillos

CONIDIA

Laboratorydiagnosis

Specimen:sputum,biopsymaterials,pusandcrustsfromlesions

KOH/HISTOPATHEXAM CultureatRoomTemperature Cultureat37C IDofcultures Otherdiagnosittest

- yeastcellswithmultiplenarrow-basedbuds

Septatehyphaewithnotypical

patternofsporulation

YeastcellswithMariners/

steeringwheelappearance

- Characteristicfeature

ExoantigentestDNAprobe

Skintest(paracoccidioidin)

- Stillofnotmuchuse

Serology

- CF- Immunodiffusion(betterchoicethanCF)

Treatment

Ketoconazole,itraconazole,sulfadrugs,AmphotericinB

- MoreofamphotericinBsincemostofthesearesystemicinfections

SurgicalExcisionoflocalizedlesions


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PENICILLIOSISMARNEFFEI

CHARACTERISTICS OCCURSAS CAUSEDBY RESERVOIROFINFECTION HABITAT INFECTIOUSPARTICLES

EndemicinSOUTHEAST

ASIA

(Thailand,China,Hong

Kong,Vietnam,Indonesia,

Taiwan,India)

Naturallyoccurinfections

havebeenfoundin

bamboorats

Becomeanearlyindicator

ofHIVinfectioninendemic

areas

- EspeciallyThailandwhereHIVprevalenceishigh-Notconsideredopportunisticbecauseit

infectsboth

immunocompetentand

immunocompromised

patients

PulmonaryInfection

-Acuteorchronic-Singlelesiontomilliaryspread

DisseminatedInfection

- SimilartodisseminatedHistoplasmosis(RES

INVOLVEMENT)

ThereisNOasymptomatic

infection

ChestX-Ray

-Mimicanylesionsinthelungs/infiltrates

-Singleormiliary

Penicilliummarneffei

-onlyspeciesofpenicillium

thatisTHERMALLY

DIMORPHIC

- ReproducesbySCHIZOGONY

(TRANSVERSEFISSION)

o Notthroughasexualprocessof

budding

o Hasmoldandyeast

o Dividesintotwo

BambooRats

Unknown

Conidia

LaboratoryDiagnosisandTreatment

Specimen:blood,bonemarrow,urine,stool,CSF,skinandvariousinternalorgans

KOH/HistopathExam Cultureatroomtemperature Cultureat37C IDofCultures Treatment

Small,yeastcellswith

transverseseptum(dueto

transversefission)

-dividesequallyintotwo

Conidiophores branchinto

metullaewhichsupportthe

phialidesthatbearchainsof

conidia(calledthePENICILLOUS

STRUCTURE[PAINTBRUSHLIKE]

Coloniesproducediffusiblered

pigment

-uniquecharacteristic

Roundtoovalyeastcellswith

cross-walls

o Exoantigentesto Conversiontoyeastform

Itrconazole,ketoconazole

AmphotericinB

-seriouslyillordisseminated

infections

fungi - respiratory 1

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