32 Micro Fungal Dz by Wenlu Flashcards
What are the three categories of sources that cause cutateous fungal infection?
What is the source of subcutaneous fungal infection?
Anthrophilic – infected tissue
Zoophilic – source is from animal (pet)
Geophilic – source from soil
Puncture or Abrasion
What is the Dx for Cutaneous fungal infection?
What is the Dx for Subcutaneous fungal infection?
C: KOH mounts and culture for morphology
S: KOH mounts if lesions on surface of skin and biopsies, then histology and culture
What is the Tx and Px for Cutaneous fungal infection?
What is the Tx for Subcutaneous fungal infection?
C: antifungal cream. Px: exposure avoidance, reduce skin moisture
S: Oral Azole Tx and surgical intervention
What is the Epidemiology for Cutaneous fungal infection?
What is the Epidemiology for Subcutaneous fungal infection?
Cutaneous are the most COMMON fungal diseases. Ex: dermatophytes, such as Athlete’s foot, ringworm, etc…
Subcutaneous are RARE infections, cause by soil or vegetation fungi
What are the names of ILLNESSES associated with Cutaneous fungal infections?
What are the names of ILLNESSES associated with Subcutaneous fungal infections?
C: Dermatophytoses, Tinea Versicolor, Tinea Nigra
S: Spororichosis, Chromoblastomycosis
What are genera that cause Dermatophytoses?
What species causes Tinea Versicolor?
What species causes Tinea Nigra?
D: Epidermophyton, Trichophyton, Microsporum
TV: Malassezia furfur
TN: Cladosporidium wernekii
What is the organism that causes Spororichosis?
What is the type of organism that causes Chromoblastomycosis?
S: Sporothrix scenii
C: Dematiaceous fungi (with brown/black melanin)
What are general properties of…
Dermatophytoses?
Tinea Versicolor?
Tinea Nigra?
D: Filamentous, septate hyphae in keratinized structures
Micro- and macroconidia
Fluoresce in UV
TV and TN: Dimorphic with yeast and hyphae in infected tissue
What are clinical features of…
Dermatophytoses?
Tinea Versicolor?
Tinea Nigra?
D: Funal infection, termed“tinea” followed by body part; fungi affect hair
TV: Hypopigmented areas on skin
TN: Brown spots on skin produced by fungal melanin
What are the general properties of…
Spororichosis?
Chromoblastomycosis?
S: Dimorphic, budding yeast at 37C and hyphae at 25C
D: Dermatiaceous fungus with brown/black melanin
What are the clinical features of…
Spororichosis?
Chromoblastomycosis?
S: Nodular lesions from site of inoculation, disseminated infection in immunosuppression
C: Slow-growing wart-like lesions with brown fungal cells
What are general features of Primary Systemic Fungal Pathogens?
- Infect healthy hosts
- Classic thermal dimorphism (soil saprophytes 25C, yeast in body 37C)
- Inhalation transmission, no Person to Person transmission
- Cell-mediated immunity resulting in granuloma; possible latent state
- Skin test (DTH), hazardous lab cultures
What are the SPECIES and ILLNESSES associated with Primary Systemic Fungal Pathogens?
Coccidioidomycosis (Valley Fever) Coccidioides, immitis, posadasii
Histoplasmosis Histoplasma capsulatum
Blastomycosis Blastomyces dermatitidis
(North American blastomycosis)
Paracocidiosdomycosis Paracoccidioides brasiliensis
(South American blasomycosis)
What are the MORPHOLOGICAL properties of... Coccidioidomycosis? Histoplasmosis ? Blastomycosis? Paracocidiosdomycosis?
C: Barrel-shaped anthroconidia. SPHERULES w/ endospores in host
H: Environmental – septate, micro- and macroconidia. Ovoid yeast, “CAPSULAR” appearance
B: Large yeast at 37C – SINGLE BUDS with BROAD BASE. Pear-shaped conidia in molds.
P: 37C – thick-walled MULTIPLE BUDS with WAGON WHEEL appearnce Pear-shaped conidia in molds
What are the KEY PATHOGENIC properties of... Coccidioidomycosis? Histoplasmosis ? Blastomycosis? Paracocidiosdomycosis (not mentioned)
C: SPHERULES release ENDOSPORES. Neutrophiles CANNOT kill. T-cells DO kill; if not, disease can lodge in other organs
H: Proliferate in Macrophage, migrate to lymph, spleen, liver. Yeast INCREASE pH and DEACTIVATE POLYPHAGOSOME
B: Proliferate in Macrophage. BAD1 surface protein increases MO uptake. Cell-mediated immunity eventually kills
What are the pathogenic properties of Coccidioimycosis?
Inhaled conidia form spherules; rupturing releases endospores to bcm spherules
Endospore resist neutrophils
MO, neutrophil response
Cell-med immunity 2-4 weeks
What are the pathogenic properties of Histoplasmosis?
Inhaled spores germinate in lung, proliferate in MO and migrate to lymph nodes, spleen, liver; mostly IC
Yeast increase pH of phagolysosome and inactivates host enzymes
Widely spread before protective immunity
What are the pathogenic properties of blastomycosis?
Inhalation of spores from soil, multiply in lung, into blood and lymphatics to organs when multiply in MO
Bad1 – surface protein, promote uptake by MO
Cell-med immunity in weeks – DTH, proliferating T-cells, circulating abs
What are the KEY CLINICAL features of…
Coccidioidomycosis?
Histoplasmosis ?
Blastomycosis?
ALL: usually asymptomatic
C: sometimes respiratory symptoms. May progress to CAVITY FORMATION. 10% have ERYTHEMA NODOSUM from protective immunity
H: self-limiting flu. May progress to chronic histoplasmosis LIKE TB GRANULOMA, susceptible people have lung defects
B: flu-like symptoms. May develop in lungs with TROPISM for SKIN and BONE
What are the Dx for... Coccidioidomycosis? Histoplasmosis ? Blastomycosis? Paracoccidioidomycosis?
All: demonstrate dimorphism of culture and serotests
C: KOH mounts, fungal stains, SABOURAUD’S AGAR
H: WRIGHT-STAINED SMEAR of blood. Fungal stain in culture. ANTIGEN in URINE.
B: KOH mounts, stained biopsies for MORPHOLOGY: SINGLE BUD BROAD BASE. Note: antigen cross reactive with Histoplasma capsulatum
P: KOH mounts, stained biopsies for MORPHOLOGY: MULTIPLE BUD WAGON WHEEL
What is Tx for ALL primary systemic fungal pathogens?
Usually self-limiting
If severe, AMPHOTERICIN B, FLUCONAZOLES
What are endemic areas for... Coccidioidomycosis? Histoplasmosis ? Blastomycosis? Paracoccidioidomycosis?
C: Southwestern US. Positive cultures from soil
H: Temperate, subtropical, tropical. Ohio, Mississippi Valley
B: MS, OH valleys, Carolinas; rec activity in wooded areas along waterways, Severe infection in dogs
P: Rural Latin America
How severe are Opportunistic Systemic Fungal Pathogens?
Most severe in compromised hosts; mortality approaches 100% in untreated; always require anti-fungal therapy
What are the SPECIES and ILLNESSES that constitute the Opportunistic Systemic Fungal Pathogens?
Crytococcus: Cryptococcus neoformans, gattii
Candidiasis: Candida albicans
Aspergillosis: Aspergillus fumigatus, A. flavus
Mucor-, Zygo-, and Phycomycosis: Mucor, Rhizopus
Pneumocystis Pneumonia (PCP): Pneumocystis jiroveci
Which opportunistic systemic fungal infections are MONOMORPHIC?
Which form do they grow in?
Aspergillosis: Aspergillus
Mucor-, Zygo-, and Phycomycosis: Mucor, Rhizopus
Both growy only in MYCELIAL FORMS
What is the morphological difference between
Aspergillus and Mucor, Rhizopus?
Aspergillus form HYPHAE which ARE SEPTATE and V-SHAPED
Mucor, Rhizopus form HYPHAE which ARE NOT SEPTATE and form RIGHT ANGLE BRANCHES
What are the most common infections…
Cryptococcus
Candidiasis
Crypt: Most common life-threatening fungal infection. Menengitis
Cand: Most common in life-threatening fungal infections from clinical etiologies; common nosocomial (adv medical procedures)
What are the growth characteristics and general features of... Crytococcus Candidiasis Aspergillosis Pneumocystis Pneumonia (PCP)
Crypt: Basidiomycetes, grow as yeast on agar
Prominent polysaccharide capsule (GXM)
Urease (+)
Cand: Budding yeast at 25C; germ-tubes, vegetative (not aerial) hyphae at 37C, polymorphic intermediate forms EXISTS IN BOTH FORMS IN HOST
Asp: Mycelial (mold) form only, NOT dimorphic
Aerial, septate hyphae in culture; airborne conidiospores
Pneu: Cysts release sporozoites; mature to pleomorphic trophozoite. Absence of ergosterols presence of cholesterol in cell membrane
What are the locations and sources of... C. neoformans C. gattii Candidiasis Aspergillosis Pneumocystis Pneumonia (PCP)
C. neoformans – soil with bird droppings INHALED
C. gattii – trees, also affect immunocompetant INHALED (unlike Bill Clinton)
Cand: ENDOGENOUS often NOCOSMIAL in mucous membranes, digestive tracts, not free-living in nature (sometimes pt to pt transmission)
Asp: Ubiquitous in envionment SPORES IN LUNGS or EPITHELIAL SURFACE
Pneu: Specific pathogens for each animal species, no cross-species infection AEROSOL TRANSMISSION
What are the PATHOGENIC features of…
Cryptococcus
Cryp: Capsule not efficiently eliminated, prevent normal cell function
Pheno oxidases: dopamine → melanin; protect from oxidate damage by host
Preferene for CNS through microcapilaries of BBB, or by delivery in phagocytic cells
What are PATHOGENIC features of…
Candidiasis
Source is endogenous, P2P spread poss
Hyphae attach to epithelial cells; invade keratinocyte layers of mucosa; white punctate lesions
Numerous adhesins for attachment, biofilms on med equipment; escape biofilm and spread to new locations (mucosal and bloodstream)
Ability to interconvert between growth morphologies
What are PATHOGENIC features of…
Aspergillus?
Spores land on exterior suface, or lungs of hosts; germ tubes from conidia colonize cavity lesions
Hyphae grow rapidly and penetrate human tissue in immunosuppressed
Septate spores with V-shaped branching in tissue
What are PATHOGENIC features of…
Pneumocystis
Aerosol transmission from pts with pneumonia, or P2P contact
Loss of CD4+ immunity → susceptibility
Inhaled cysts → inflammatory response of plasma cells, frothy exudate prevent O2 exchange
What are KEY PATHOGENIC features of... Crytococcus Candidiasis Aspergillosis Pneumocystis Pneumonia (PCP)
Cryp: CAPSULE. PHENOL OXIDASE converts dopamine to malanin as protection. TARGETS CNS
Cand: WHITE PUNCTATE lesions. ADHESIONS. BIOFILMS on medical equipment. INTERCONVERTS between growth morphologies in host. Common in HIV.
Asp: GERM TUBES colonize CAVITIES. HYPHAL GROWTH in host. SEPTATE SPORES with V-SHAPED branches
Pneu: AEROSOL between people. COMMON in HIV. Inhaled cysts → inflammatory response of plasma cells, FROTHY EXUDATE prevents O2 exchange
What are KEY CLINICAL features of... Cryptococcus (also C. neoformans only) Candidiasis Aspergillosis Pneumocystis Pneumonia (PCP)
Cryp: Chronic MENINGOENCEPHALITIS with slow, insidious onset (headach, stiff neck, lung infection)
C. neoformans – also UTI and respiratory tract infections
Cand: Diaper rash, thrush, vaginitis, esophageal
Prominent post-HIV infection, chemotherapy, sepsis
Asp: Invasive infection on pts with LOWER NEUTROPHILS, organ transplants, immunosuppresive therapy, COPD
Pneu: Asymptomatic common. Associated AIDS, major cause of Mortality with HIV. SUDDEN ONSET FEVER, non-prod cough, dyspnea, tachypnea; CXR show DIFFUSE INTERSTITIAL PNEUMONIA; require O2 THERAPY
What occurs with CHRONIC CANDIDIASIS?
Chronic mucocutaneous candiasis (CMC) – IL-17 med T-cell immunity deficiency
What are clinical symptoms for Aspergillus (full answer)?
Invasive infection on pts with lower neutrophils, organ transplants, immunosuppresive therapy, COPD
Fever, cough, chest pain, short breath
Aspergillomas (fungus ball)
Allergic Bronchopulm. Aspergillosis (ABPA)
What is Dx for Cryptococcus?
Presence of capsular antigen in CSF, plasma, urine
India ink wet mount for encap organisms; mucicarmine, PAS, metanamine stains
Cultured, but not common
What is Dx for Candidiasis?
DTH skin test for status of immunity
Sabauraud agar, smooth white colonies
Lack of tests on serum, blood
Molecular methods
Rapid germ tube test
ID based on pattern of fermentation and assimilation in carbon sources
What is Dx for Aspergillus?
Biopsy of infected mateial for morphology
Serum test for antigen galactomannan (not very sensitive)
Eosinophilia, IgE abs for antigens to diagnose ABPA (What is ABPA)
What is the Dx for Pneumocystis?
CANNOT culture human forms, grow in animals
Methanamine silver stain, fluorescent stain with specific abs, PCR
Resist amphotericine B
Susceptible to some anti-parasitic agents (e.g. bactrim)
What is Px for Pneumocystis?
Keep immunosuppressed from infected hosts
What is the OTHER Candidiasis?
What drug is it resistant to?
C. glabrata – 2nd most prevalent, resist azoles
