Micro- Fungi + Parasites Flashcards
Candida albicans
Morphology
Transmission and Reservoir
Diseases
Treatment and Prevention
yeast
———————–
- mouth, skin, GI tract, vagina
- occurs when there is a breach in the host immune defense
- usually endogenous infection
- can be passed between people in some instances
———————–
- oral thrush
- esophagitis
- vaginitis
- bloodstream infection
- abscesses
- catheter-associated UTI
- can disseminate to multiple organs
———————–
mucocutaneous:
- Nystatin
- oral or topical azoles
systemic:
- azoles
- Echinocandins
- Amphotericin B
Candida glabrata
Morphology
Transmission and Reservoir
Diseases
Treatment and Prevention
yeast
- mouth, skin, GI tract, vagina
- occurs when there is a breach in the host immune defense
- seen when C. albicans is decreased by fluconazole treatment
- oral thrush
- esophagitis
- vaginitis
- bloodstream infection
- abscesses
- same as Candida albicans
Cryptococcus neoformans
Morphology
Transmission and Reservoir
Virulence Factors
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
yeast
———————–
- soil contaminated by bird droppings
- inhalation
- immunocompromised hosts
———————–
- polysaccharide capsule
- melanin to protect against oxidative stress
———————–
1) inhaled
2) travels to CNS and other organs
———————–
pneumonia
meningoencephalitis
- occurs in up to 10% of people with AIDS
- persistent, dull headache, malaise, fever, night sweats, meningeal signs may or may not be present
skin & bloodstream infections
———————–
- India ink stain of CSF
- Cryptococcal antigen test on blood or CSF: measuring polysaccharide antigen by ELISA or latex agglutination
- CSF culture
———————–
- Amphotericin B + 5-flucytosine, followed by fluconazole
Cryptococcus gattii
Morphology
Transmission and Reservoir
Virulence Factors
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
yeast
———————–
-inhalation
- tropical areas
———————–
- polysaccharide capsule
- melanin to protect against oxidative stress
———————–
1) inhaled
2) travels to CNS and other organs
———————–
pneumonia
meningoencephalitis
skin & bloodstream infections
———————–
- stain w/ India ink
———————–
- same as Cryptococcus neoformans
Pneumocystis jiroveci (Pneumocystis carinii)
Morphology
Transmission and Reservoir
Diseases
Diagnosis
Treatment and Prevention
yeast
lacks ergosterol
———————–
- inhalation of cyst in childhood
- reactivation when immunocompromised
———————–
Pneumocystis jiroveci Pneumonia (PJP)
- gradual onset of fever, dyspnea, and non-productive cough
———————–
- CXR with bilateral interstitial infiltrates, rarely focal or cavitary
———————–
- TMP/SMX
Aspergillus flavus
Morphology
Transmission and Reservoir
Virulence Factors
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- rotting plants
- inhalation
———————–
aflatoxin B1 is a powerful carcinogen
———————–
———————–
hepatocellular carcinoma
———————–
- branching, septate hyphae
———————–
- Amphotericin
- Voriconazole
- Posaconazole
- Itraconazole
- Echinocandins
Aspergillus perasiticus
Morphology
Transmission and Reservoir
Virulence Factors
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- rotting plants
- inhalation
———————–
aflatoxin B1 is a powerful carcinogen
———————–
———————–
hepatocellular carcinoma
———————–
- branching, septate hyphae
———————–
same as A. flavus:
- Amphotericin
- Voriconazole
- Posaconazole
- Itraconazole
- Echinocandins
Aspergillus fumigates
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
mold
- rotting plants
- inhalation
- 1) inhalation of spores
2) evasion of pulmonary macrophages or neutrophils
3) local infection in the lung
4) entry into blood vessels
5) dissemination to other sites (e.g. brain) - airway colonization
- allergic bronchopulmonary aspergillosis (ABPA)
- treacheobronchitis
- sinusitis
- aspergilloma (fungus ball)
- invasive pulmonary aspergillosis
- disseminated aspergillosis
- branching, septate hyphae
- same as A. flavus
Aspergillus niger
Morphology
Transmission and Reservoir
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- rotting plants
- inhalation
———————–
chronic otitis externa
———————–
- branching, septate hyphae
———————–
- same as A. flavus
Zoophilic Dermatophyte:
Microsporum canis
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- animals
- contact
———————–
infect keratinized layer of skin
———————–
tinea corpis (ring worm), tinea capitis (scalp infection)
———————–
- skin scrapings or nail clippings can be examined microscopically or cultured
- fluoresces green under UV light
———————–
- Imidazoles
- Terbinafine
- Azoles
Anthropophilic Dermatophyte:
Trichophyton rubrum
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- humans
- contact
———————–
infect keratinized layer of skin
———————–
tinea pedis (athlete’s foot), tinea cruris (jock itch)
———————–
- skin scrapings or nail clippings can be examined microscopically or cultured
- Imidazoles
- Terbinafine
- Azoles
Zygomycetes:
Mucor
Absidia
Rhizopus
Rhizomucor
Morphology
Transmission and Reservoir
Diseases
Diagnosis
Treatment and Prevention
mold
———————–
- inhalation
- risk factors: immune deficiency, diabetes, hemochromatosis
———————–
pneumonia
sinusitis
brain abscess
thrombosis
infarction
———————–
- non-septate hyphae that branch at right angles
———————–
- Amphotericin B
- Posaconazole
Sporothrix schenckii
Morphology
Transmission and Reservoir
Diseases
dimorphic fungi
(mold at ambient temperature, yeast at 37C)
———————–
soil, infected plant products, wood, roses
- puncture wound
———————–
cutaneous disease with local lymphatic spread
Histoplasma capsulatum
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
dimorphic fungi
———————–
- soil in Mississippi & Ohio River Valleys
- inhalation
———————–
-disseminated from respiratory tract
———————–
histoplasmosis
pulmonary infection; can be disseminated
Coccidioides spp.
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
dimorphic fungi
———————–
-soil in SW US
- inhalation
- no person-to-person transmission
———————–
1) mycelia (infectious) form in soil
2) spores within humans convert to spherules
3) spherules rupture and release endospores, which form more spherules
- disseminated from respiratory tract
———————–
valley fever:
- can be asymptomatic
- primary disease usually resolves spontaneously
- immunocompromised patients are more susceptible to chronic or disseminated infection
- complications:
1) cavity formation
2) dissemination to skin
3) meningitis
4) pneumonia
Blastomyces dermatitidis
Morphology
Transmission and Reservoir
Pathogenesis
Diseases
dimorphic fungi
———————–
- soil in Mississippi & Ohio River Valleys
- inhalation -
———————–
disseminated from respiratory tract
———————–
blastomycosis:
pulmonary infection that spreads to skin and bone
Dermatiaceous molds
Morphology
Diseases
mold
black or brown pigment due to melanin
———————–
cutaneous & subcutaneous infection,
fungal meningitis
Penicillium marneffei
Transmission and Reservoir
- SE Asia
- immunocompromised hosts
Fusarium
Transmission and Reservoir
- patients with hematological malignancies and bone marrow transplantation
Scedosporium
Transmission and Reservoir
- post-traumatic infection in immunocompetent
- disseminated infection in immunocompromised
Entamoeba histolytica
Morphology
Transmission and Reservoir
Virulence Factors
Pathogenesis
Diseases
Treatment and Prevention
protazoa
———————–
- fecal-oral
- contaminated food or water
- rarely found in US
———————–
- cysts
———————–
1) cyst is excreted by a person
2) fecally contaminated food or water is ingested
3) becomes a trophozoites in the gut and attaches to colonic mucosa
4) may penetrate mucosa and travel to the liver via the portal circulation, forming liver abscesses
5) more cysts are formed in the gut and shed
———————–
bloody diarrhea
liver abscess
incubation time of 2-4 weeks
———————–
Metronidazole
Entamoeba histolytica
Morphology
Transmission and Reservoir
Virulence Factors
Pathogenesis
Diseases
Treatment and Prevention
protazoa
———————–
- fecal-oral
- contaminated food or water
- rarely found in US
———————–
- cysts
———————–
1) cyst is excreted by a person
2) fecally contaminated food or water is ingested
3) becomes a trophozoites in the gut and attaches to colonic mucosa
4) may penetrate mucosa and travel to the liver via the portal circulation, forming liver abscesses
5) more cysts are formed in the gut and shed
———————–
bloody diarrhea
liver abscess
incubation time of 2-4 weeks
———————–
Metronidazole
Acanthamoeba
Morphology
Transmission and Reservoir
Diseases
protozoa
———————–
- contaminated water
- contact lenses
———————–
lens opacity;
can lead to blindness
Naegleria fowleri
Morphology
Transmission and Reservoir
Virulence Factors
Pathogenesis
Diseases
Diagnosis
Treatment and Prevention
protazoa
- warm freshwater & soil
- southern US
- enters the nose when swimming
- brain infection
- fatal