Fungi: Opportunistic Fungal Infections Flashcards
List the opportunistic fungal infections
- candida albicans
- aspergillus fumigatus
- Cryptococcus neoformans
- mucor
- rhizopus
- pneumocystis jirovecii
Candida albicans is a
dimorphic fungus, but differs from other dimorphic fungi in that it forms pseudohyphae and budding yeast at 20°C (yeast form), and germ tubes at 37°C (mold form)
Candida albicans forms
- germ tubes at 37°C (mold form)
2. pseudohyphae and budding yeast at 20°C (yeast form)
Candida albicans fungi are
catalase positive
Candida albicans can cause
- cutaneous candidiasis in areas exposed to heat and humidity (diaper rash in infants)
- disseminated disease in immunocompromised patients (especially those with neutropenia)
- HIV-associated esophagitis (an AIDS-defining illness), which presents with adherent grey/white pseudomembranes
- infection of the vulva and vagina (vulvovaginal candidiasis), which typically presents with vulvar pruritus and a thick white vaginal discharge
oral thrush due to Candida albicans
oral thrush due to Candida albicans (which commonly presents as white patches on the lining of the mouth) is associated with oral or inhaled steroid use and immunosuppression
the white patches of Candida albicans fungi that form on lining of the mouth can be
scraped off
Candida albicans infection can be diagnosed with
KOH mount of oral/vaginal/skin scrapings (microscopic examination will show budding yeast and pseudohyphae)
esophageal candidiasis is an
AIDS-defining illness that generally occurs in patients with a CD4+ count <200
risk factors for vulvovaginal candidiasis
uncontrolled diabetes mellitus, antibiotic use, and high estrogen levels (i.e. oral contraceptives, pregnancy)
the vaginal pH in vulvovaginal candidiasis
the vaginal pH typically remains normal (3.8-4.5) in vulvovaginal candidiasis
Candida infective endocarditis commonly affects
Candida infective endocarditis commonly affects the tricuspid valve and is associated with IV drug use, prosthetic heart valves, and indwelling lines
_________ is effective against Candida albicans
fluconazole
__________ can be used to treat Candida albicans infections (typically when resistance or intolerance to antifungals is suspected or proven)
amphotericin B
_________ is used topically to treat Candida skin infection (but is not indicated for vaginal candidiasis) and orally for thrush
nystatin
________ can be used to treat oral, esophageal, and systemic candidiasis
caspofungin/micafungin (echinocandins antifungals)
Aspergillus spp. fungi are
catalase positive
________ produced by Aspergillus flavus can be found in nuts, legumes, wheat, and other crops
aflatoxins
aflatoxins
aflatoxins of Aspergillus flavus have been linked to hepatocellular carcinoma
Aspergillus spp. have
septate hyphae that form 45-degree angle branches
Aspergillus is transmitted via
inhalation of spores (contained in fruiting bodies)
allergic bronchopulmonary aspergillosis (a type I hypersensitivity reaction) presents with
migratory pulmonary infiltrates, wheezing, and increased serum IgE (most commonly in cystic fibrosis and asthma patients)
elevated serum IgE is a common clinical manifestation of
allergic bronchopulmonary aspergillosis (a type I hypersensitivity reaction)
colonization of Aspergillus in the lung
colonization of Aspergillus in the lung (“fungus balls” that usually form in old pulmonary cavities) may cause fever, hemoptysis, and cough
aspergillomas (“fungus balls”) typically develop in
old pulmonary cavities (from tuberculosis, sarcoidosis, emphysema, etc.)
aspergillomas (“fungus balls”) classically appear as
radiopaque structures that shift with change in position on chest X-ray (gravity-dependent)
invasive pulmonary aspergillosis
invasive pulmonary aspergillosis (angioinvasive, airway centered invasive) occurs in immunosuppressed and neutropenic patients