DO mycology Slides 2008 - UAB School of Optometry year/micro/powerpoint/mycology.pdf · Antifungal...
Transcript of DO mycology Slides 2008 - UAB School of Optometry year/micro/powerpoint/mycology.pdf · Antifungal...
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MycologyMycology
Dental / Optometry MicrobiologyDental / Optometry MicrobiologyStephen A. Moser, Ph.D.Stephen A. Moser, Ph.D.
10/10/200810/10/2008
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Reading AssignmentReading Assignment
Medical Microbiology, 4th EditionMurray, PR, et al
Chapters 66 – 71.
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EpidemiologyEpidemiology
GeographyGeography Endemic mycosesEndemic mycoses Worldwide mycosesWorldwide mycoses
Transmission of infectionTransmission of infection Respiratory inhalation (systemic mycoses)Respiratory inhalation (systemic mycoses) Cutaneous inoculation (sporotrichosis)Cutaneous inoculation (sporotrichosis) Systemic invasion by opportunistic normal floraSystemic invasion by opportunistic normal flora
(candidiasis)(candidiasis) Contact with infected hosts (dermatophytoses)Contact with infected hosts (dermatophytoses)
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Epidemiology (Cont.)Epidemiology (Cont.) Risk factors and manifestations of diseaseRisk factors and manifestations of disease
True pathogens versus opportunistsTrue pathogens versus opportunists Environmental risk factors for systemic fungalEnvironmental risk factors for systemic fungal
diseasedisease•• Location and travelLocation and travel•• OccupationOccupation
Host defenses and susceptibility to systemicHost defenses and susceptibility to systemicfungal disease (CMI most important)fungal disease (CMI most important)
•• Congenital and acquired T cell deficiencies (includingCongenital and acquired T cell deficiencies (includingAIDS)AIDS)
•• Immunosuppression (transplants and malignancies)Immunosuppression (transplants and malignancies)•• Diabetes mellitusDiabetes mellitus
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Endemic Distribution for BlastomycosisEndemic Distribution for Blastomycosis
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General CharacteristicsGeneral Characteristics
AerobicAerobic - obligate or facultative - obligate or facultative EukaryoticEukaryotic: membrane bound nucleus: membrane bound nucleus
and cytoplasmic organelles (may beand cytoplasmic organelles (may bemultinucleate)multinucleate)
AchlorophyllousAchlorophyllous MorphologyMorphology (unicellular or (unicellular or multicellularmulticellular)) Saprophytic (heterotrophic)Saprophytic (heterotrophic)
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Characteristics of Fungal CellsCharacteristics of Fungal Cells
Cell wallCell wall: : multilayered polysaccharidemultilayered polysaccharide Cellulose, glucans, mannans, chitin, polypeptidesCellulose, glucans, mannans, chitin, polypeptides Absence of teichoic acids, peptidoglycan, LPSAbsence of teichoic acids, peptidoglycan, LPS
Cell membraneCell membrane PhospholipidPhospholipid bilayerbilayer Ergosterol (relate to chemotherapy)Ergosterol (relate to chemotherapy)
CytoplasmCytoplasm - typical eukaryotic organelles- typical eukaryotic organelles NucleusNucleus - either - either uninucleateuninucleate or multinucleate or multinucleate
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Characteristics of Fungal CellsCharacteristics of Fungal Cells
CapsuleCapsule Present in some species (e.G. Present in some species (e.G. CryptococcusCryptococcus
neoformansneoformans)) Amorphous polysaccharide coatingAmorphous polysaccharide coating FunctionsFunctions and activitiesand activities
AntiphagocyticAntiphagocyticAntigenicAntigenic
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Growth formsGrowth forms Yeast - unicellular fungi which reproduce byYeast - unicellular fungi which reproduce by
budding (budding (CryptococcusCryptococcus)) Mold - hyphae (mycelium)Mold - hyphae (mycelium)
Septate hyphae (Septate hyphae (AspergillusAspergillus))
Non-septate, Non-septate, coenocyticcoenocytic hyphae ( hyphae (MucorMucor)) PseudohyphaePseudohyphae ( (Candida albicansCandida albicans)) Thermal dimorphismThermal dimorphism
Characteristics of Fungal CellsCharacteristics of Fungal Cells
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Differences Between BacteriaDifferences Between Bacteriaand Fungiand Fungi
PROPERTY FUNGI BACTERIA
Cell diameter 5-50 microns 1-5 microns
Nucleus Eukaryotic prokaryotic
Cytoplasmic organelles Present absent
Cell membrane sterols present (ergosterol) absent (exceptMycoplasma)
Cell wall chitin, glucans,mannans, peptides
teichoic acids,peptidoglycan, LPS
Metabolism Mainly aerobes, facultativeanaerobes
obligate and facultativeaerobes and anaerobes
Thermal dimorphism Common in many pathogenicspecies
absent
Differences Between Differences Between Bacteria and FungiBacteria and Fungi
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Examples of Yeast &Examples of Yeast &PseudohyphaePseudohyphae
Pseudohypha
Blastoconidia
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Example of True Septate HyphaeExample of True Septate Hyphae
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Non-septate HyphaeNon-septate Hyphae
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Blastomyces dermatitidisBlastomyces dermatitidis Thermal ThermalDimorphismDimorphism
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Asexual ReproductionAsexual Reproduction
Conidia (spores) Conidia (spores) –– asexual structures asexual structures BlastosporesBlastospores –– formed by budding yeasts formed by budding yeasts
((BlastomycesBlastomyces)) ChlamydosporesChlamydospores –– terminal or intercalary cells terminal or intercalary cells
with thick walls (with thick walls (Candida albicansCandida albicans)) ArthrosporesArthrospores –– formed by fragmentation of formed by fragmentation of
hyphae (hyphae (Coccidioides immitisCoccidioides immitis)) SproangiosporesSproangiospores –– formed in sporangia by formed in sporangia by
cleavage (cleavage (RhizopusRhizopus))
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Classification Based onClassification Based onSexual PhaseSexual Phase
AscomycetesAscomycetes: : Aspergillus,Aspergillus, HistoplasmaHistoplasma,,BlastomycesBlastomyces, Dermatophytes, Dermatophytes
BasidiomycetesBasidiomycetes: : CryptococcusCryptococcus,,MushroomsMushrooms
ZygomycetesZygomycetes: Order Mucorales - : Order Mucorales - MucorMucor,,RhizopusRhizopus
DeuteromycetesDeuteromycetes (Fungi Imperfecti): (Fungi Imperfecti):SporothrixSporothrix, , Coccidioides, CandidaCoccidioides, Candida
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Clinical Types of FungalClinical Types of FungalInfectionsInfections
TYPE DISEASE ORGANISM
1. Superficial Pityriasis versicolor Malassezia furfur
2. Cutaneous Ringworm (Tinea)
Candidiasis
Trichophyton species
Candida albicans and others
3. Subcutaneous Sporotrichosis Sporothrix schenckii
4. Systemic Pathogenic Fungi
Histoplasmosis Histoplasma capsulatum
Blastomycosis Blastomyces dermatitidis
Coccidioidomycosis Coccidioides immitis
Paracoccidioidomycosis
Opportunistic Fungi
Paracoccidioides brasiliensis
Aspergillosis Aspergillus fumigatus and
others
Cryptococcosis Cryptococcus neoformans
Candidiasis Candida albicans and others
Zygomycosis Mucor and Rhizopus species
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Routes of InfectionRoutes of Infection
Inhalation of spores Inhalation of spores –– major factor major factor Inoculation of spores into skinInoculation of spores into skin Disease by normal flora in compromisedDisease by normal flora in compromised
host (Candida)host (Candida) HypersensitivityHypersensitivity Contact with infected hostContact with infected host
(Dermatophytes)(Dermatophytes) MycotoxinsMycotoxins
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Laboratory Diagnosis of FungalLaboratory Diagnosis of FungalInfectionsInfections
Microscopic Examination of tissues and bodyMicroscopic Examination of tissues and bodyfluidsfluids Gram stainGram stain GiemsaGiemsa India InkIndia Ink Potassium hydroxide (KOH) wet prepPotassium hydroxide (KOH) wet prep Hematoxylin and Eosin stainHematoxylin and Eosin stain Periodic-Acid Schiff stain (PAS)Periodic-Acid Schiff stain (PAS) Gomori-Methenamine Silver stain (GMS)Gomori-Methenamine Silver stain (GMS) Mucicarmine or Mucicarmine or AlcianAlcian Blue stain Blue stain
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Budding Yeast - Gram StainBudding Yeast - Gram Stain
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Encapsulated Yeast - India InkEncapsulated Yeast - India Ink
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KOH Prep - Broad-base Budding YeastKOH Prep - Broad-base Budding Yeast
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H&E Stain - Budding YeastsH&E Stain - Budding Yeasts
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PAS Stain - Yeast and HyphaePAS Stain - Yeast and Hyphae
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GMS Stain - Septate HyphaeGMS Stain - Septate Hyphae
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Mucicarmine Stain - Mucicarmine Stain - C. neoformansC. neoformans
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Histopathological Response toHistopathological Response toFungal InfectionFungal Infection
Acute pyogenic abscess (Candida)Acute pyogenic abscess (Candida) Chronic granuloma formationChronic granuloma formation
(Histoplasma)(Histoplasma) Chronic, localized dermal inflammationChronic, localized dermal inflammation
(Dermatophytes)(Dermatophytes) Mixed pyogenic and granulomatousMixed pyogenic and granulomatous
inflammation (Blastomyces)inflammation (Blastomyces) Blood vessel invasion with thrombosis andBlood vessel invasion with thrombosis and
infarction (Mucor, Aspergillus)infarction (Mucor, Aspergillus) Hypersensitivity without tissue reactionHypersensitivity without tissue reaction
(allergic bronchopulmonary aspergillosis)(allergic bronchopulmonary aspergillosis)
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Fungal CulturesFungal Cultures
Utilize Sabouraud agar with antibioticsUtilize Sabouraud agar with antibiotics Identification criteriaIdentification criteria
Temperature of growthTemperature of growth Rate of growthRate of growth Colonial and microscopic morphologyColonial and microscopic morphology Sporulation patternSporulation pattern Biochemical reactions (yeast)Biochemical reactions (yeast)
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Fungal SerologyFungal Serology
Generally poor and not as useful as in otherGenerally poor and not as useful as in otherpathogens such as viruses and bacteria, withpathogens such as viruses and bacteria, withsome exceptions.some exceptions.
Cryptococcal antigen by latex agglutination:Cryptococcal antigen by latex agglutination:serum and CSF.serum and CSF.
CoccidioidesCoccidioides - early IgM response is useful - early IgM response is usefulfor identification of acute primary disease -for identification of acute primary disease -CSF IgG prognostic value.CSF IgG prognostic value.
Skin tests for DTH - problems:Skin tests for DTH - problems: Cross-reactivity.Cross-reactivity. High positive rate in endemic areas.High positive rate in endemic areas.
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CandidiasisCandidiasis Clinical manifestationsClinical manifestations
MucosalMucosal•• VaginitisVaginitis•• EsophagitisEsophagitis•• Oral thrushOral thrush
CutaneousCutaneous Chronic mucocutaneousChronic mucocutaneous SystemicSystemic
•• FungemiaFungemia•• Hepato-spleenicHepato-spleenic•• EndophthalmitisEndophthalmitis•• RenalRenal
Urinary tractUrinary tract
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OralOralCandidiasisCandidiasis
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PseudomembraneousPseudomembraneousCandidiasisCandidiasis
(Thrush)(Thrush)
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MucocutaneousMucocutaneousCandidiasisCandidiasis
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Candida sp. Tissue GMS StainCandida sp. Tissue GMS Stain
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AspergillosisAspergillosis
Clinical manifestationsClinical manifestations PneumoniaPneumonia AspergillomaAspergilloma Allergic bronchopulmonaryAllergic bronchopulmonary Disseminated multiorgan involvementDisseminated multiorgan involvement
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AspergillomaAspergilloma
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Aspergilloma Aspergilloma –– Gross Anatomy Gross Anatomy
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Allergic Bronchopulmonary AspergillosisAllergic Bronchopulmonary Aspergillosis
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CNS AspergillosisCNS Aspergillosis
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KOH Prep KOH Prep –– Aspergillus sp. Aspergillus sp.
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AspergillusAspergillus sp GMS Stain sp GMS Stain
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AspergillusAspergillus sp sp –– GMS Stain GMS Stain
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ZygomycosisZygomycosis
Clinical manifestationsClinical manifestations SinusitisSinusitis RhinocerebralRhinocerebral PulmonaryPulmonary RenalRenal
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RhinocerebralRhinocerebralMucormycosisMucormycosis
in Diabeticin DiabeticKetoacidosisKetoacidosis
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Postmortem Postmortem –– Rhinocerebral Mucormycosis Rhinocerebral Mucormycosis
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Non-septate Branching Hyphae (PAS)Non-septate Branching Hyphae (PAS)
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HistoplasmosisHistoplasmosis
Clinical manifestationsClinical manifestations Most cases mild or sub-clinical pulmonaryMost cases mild or sub-clinical pulmonary
diseasedisease•• Dissemination appears to be commonDissemination appears to be common
PneumoniaPneumonia Chronic progressive pulmonary (cavitary)Chronic progressive pulmonary (cavitary) HistoplasmomaHistoplasmoma DisseminatedDisseminated
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HistoplasmosisHistoplasmosis–– Calcified Calcified
LesionsLesions
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DisseminatedDisseminatedHistoplasmosisHistoplasmosis
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Histoplasmosis- GMSHistoplasmosis- GMS
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Histoplasmosis Histoplasmosis –– Bone Marrow Bone Marrow
Histiocyte
H. capsulatum
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Histoplasma capsulatumHistoplasma capsulatumIn vitro In vivo
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Risk factors for endogenous and exogenous endophthalmitisDisease and fungus Risk factors or comments
Endogenous endophthalmitis
C. albicans Central venous lines, neutropenia, abdominal surgery,intravenous drug abuse, broad-spectrum antibiotics
Candida species Central venous lines, neutropenia, abdominal surgery,intravenous drug abuse, broad-spectrum antibiotics
Aspergillus species Neutropenia, endocarditis, intravenous drug abuse, pulmonarydisease being treated with high-dose steroids, organ transplant
Fusarium species Neutropenia, intravenous drug abuse
H. capsulatum, C. immitis, B. dermatitidis, S. schenckii, C. neoformans
May accompany disseminated disease
Exogenous endophthalmitis
Fusarium species Post trauma and post keratitis
Candida species Post surgery, contaminated eye irrigates
P. lilacinus Post surgery, contaminated sterilization solutions
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FUNGAL KERATITISFUNGAL KERATITIS
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ChemotherapyChemotherapy FDA approvedFDA approved
Polyenes (Amphotericin B, lipid encapsulated forms)Polyenes (Amphotericin B, lipid encapsulated forms) Azoles (fluconazole, itraconazole, ketoconazole,Azoles (fluconazole, itraconazole, ketoconazole,
voriconazole)voriconazole) Echinocandin (Caspofungin, Micafungin, Anidulafungin)Echinocandin (Caspofungin, Micafungin, Anidulafungin) Nucleoside derivatives (5-flurocytosine)Nucleoside derivatives (5-flurocytosine) Allyamines (Terbinafine)Allyamines (Terbinafine) Microtubule disruption (Griseofulvin)Microtubule disruption (Griseofulvin)
InvestigationalInvestigational Nikkomycins (chitin synthase inhibitors)Nikkomycins (chitin synthase inhibitors) Echinocandin/pnemocandin/lipopeptide class (inhibit glycanEchinocandin/pnemocandin/lipopeptide class (inhibit glycan
synthesis)synthesis)
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Antifungal Drugs for SystemicAntifungal Drugs for SystemicMycoses - Amphotericin BMycoses - Amphotericin B
Mode of ActionMode of Action Binds to ergosterol, increases membraneBinds to ergosterol, increases membrane
permeability resulting in leakage of cytoplasmicpermeability resulting in leakage of cytoplasmiccomponents and cell death components and cell death –– Fungicidal Fungicidal
Spectrum of ActivitySpectrum of Activity Candida, Crypto, Aspergillus, Candida, Crypto, Aspergillus, HistoHisto, , BlastoBlasto, , CocciCocci,,
etcetc LimitationsLimitations
NephrotoxicityNephrotoxicity
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Mechanism of Action ofMechanism of Action ofABELCETABELCET
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Antifungal Drugs for SystemicAntifungal Drugs for SystemicMycoses - 5-flurocytosineMycoses - 5-flurocytosine
Mode of ActionMode of Action Inhibits RNA and DNA biosynthesisInhibits RNA and DNA biosynthesis
Spectrum of ActivitySpectrum of Activity Used in combination with Used in combination with AmphoAmpho B against crypto B against crypto
and Candidaand Candida Good CNS penetrationGood CNS penetration
LimitationsLimitations Narrow spectrum of activityNarrow spectrum of activity Resistance develops if used aloneResistance develops if used alone Can suppress bone marrowCan suppress bone marrow
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Antifungal Drugs for SystemicAntifungal Drugs for SystemicMycoses - FluconazoleMycoses - Fluconazole
Mode of ActionMode of Action Prevents ergosterol synthesis by inhibiting the C-14Prevents ergosterol synthesis by inhibiting the C-14
demethylationdemethylation step (cytochrome P-450 rx) step (cytochrome P-450 rx) FungistaticFungistatic
Spectrum of ActivitySpectrum of Activity Candida, Crypto, Candida, Crypto, TrichsporonosisTrichsporonosis, dermatophytes, dermatophytes
LimitationsLimitations Resistance in some Candida sp Resistance in some Candida sp –– krusei and glabrata krusei and glabrata Not effective for non-dermatophyte moulds.Not effective for non-dermatophyte moulds.
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Antifungal Drugs for SystemicAntifungal Drugs for SystemicMycoses -ItraconazoleMycoses -Itraconazole
Mode of ActionMode of Action Prevents ergosterol synthesis by inhibitingPrevents ergosterol synthesis by inhibiting
the C-14 the C-14 demethylationdemethylation step (cytochrome step (cytochromeP-450 rx)P-450 rx)
FungistaticFungistatic Spectrum of activitySpectrum of activity
Systemic mycoses, yeasts, dematiaceousSystemic mycoses, yeasts, dematiaceousmoulds and dermatophytes.moulds and dermatophytes.
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Early Diagnosis of InvasiveEarly Diagnosis of InvasiveFungal InfectionsFungal Infections
ObstaclesObstacles•• Because of Immunosuppression typical signsBecause of Immunosuppression typical signs
and symptoms of infection are frequently absentand symptoms of infection are frequently absent•• Few clinical features are uniquely specific forFew clinical features are uniquely specific for
systemic fungal infectionsystemic fungal infection•• Sputum and blood cultures are frequentlySputum and blood cultures are frequently
negativenegative•• Invasive proceduresInvasive procedures
–– May be necessary for definitive diagnosisMay be necessary for definitive diagnosis–– Are often complicated in severelyAre often complicated in severely
immunocompromised patientimmunocompromised patient
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Early Diagnosis of InvasiveEarly Diagnosis of InvasiveFungal Infections (Continued)Fungal Infections (Continued)
BenefitsBenefits Early diagnosis permits therapy ofEarly diagnosis permits therapy of
maximal effectivenessmaximal effectiveness Early intervention with antifungalEarly intervention with antifungal
therapy may help decrease the hightherapy may help decrease the highmortality rate associated with seriousmortality rate associated with serioussystemic mycosessystemic mycoses
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DISEASE ETIOLOGIC AGENTS(S) TISSUE APPEARANCE ORGANS INVOLVED
Candidiasis
Candida albicans and others
yeast, hyphae and pseudohyphae
skin, mucous membranes , heart valves
Histoplasmosis
Histoplasma capsulatum
intracellular yeast
lungs and disseminated
Blastomycosis
Blastomyces dermatitidis
thick-walled budding yeast
lungs, skin and bone
Coccidioidomycosis
Coccidioides immitis
spherules with endospores
lungs and disseminated
Aspergillosis
Aspergillus fumigatus and others
mold with septate hyphae
lungs
Cryptococcosis
Cryptococcus neoformans
encapsulated budding yeast
lungs, meninges and skin
Sporotrichosis
Sporothrix schenckii
cigar-shaped yeast (rarely observed)
skin and disseminated
Zygomycosis
Mucor and Rhizopus species
Mold with broad nonseptate hyphae
nasal sinuses, lung, GI tract
Common Deep MycosesCommon Deep Mycoses