Fungi II Flashcards
(56 cards)
Primary infections by these systemic mycoses causing organisms are usually in the
Lung
Most primary infections are inapparent and self-limiting, recognized only by immune response or
X-ray
Organisms are dimorphic, grow as yeast in tissue and mycelia in culture under usual conditions
Systemic mycoces organisms
The organisms that cause systemic mycoses can be converted to yeast form by culture on
Blood agar
Cultures of mold forms are identified by reaction of soluble antigens with specific antisera. This is called the
Exoantigen test
This is an Oucherlony double-diffusion test; a line of identity is considered
Diagnostically significant
A dimorphic fungus; in tissue Cryptococcus grows as a heavily
Encapsulated yeast
A dimorphic fungus; in tissue Cryptococcus grows as a heavily encapsulated yeast. It is the imperfect stage of a
Basidiomycete Filobasidiella
Like S. pneumoniae, H. influenzae, and N. meningitidis, it is a heavilyencapsulated pathogen that initially infects the respiratory tract and can spread from there to the brain and/or meninges
Cryptococcus
Straddles the boundary between ‘pathogen’ and ‘opportunist’
Candida
In clinical material, can appear as yeast, hyphae, or pseudophyphae
C. albicans
A diagnostic feature which separates C. albicans from other Candida is formation of
“Germ tubes” when yeast are placed in serum
Buds which in serum elongate to form the beginnings of hyphae
Germ tubes
Chronic mucocutaneous candidiasis is a hallmark of defects in
Cell-mediated immunity
Ubiquitous; important pathogens of AIDS patients, transplant recipients, and patients receiving anticancer therapy
Opportunistic fungal pathogens
What are three examples of opportunistic fungal pathogens?
Aspergillus, zygomyces, and pneumocystis carinii
A large genus, ubiquitous in soil and plant material.
-The most frequent pathogen is A. fumigatus although other species are common causes of disease
Aspergillus
The most frequent pathogen of aspergillus is
A. fumigatus
Most aspergillus infections are
Pulmonary
Most aspergillus infections are pulmonary. Infection can be local and non-invasive [‘Aspergilloma’] or invasive and
Necrotizing
Can cause thrombosis, infarction, necrosis, and hemorrhage if they penetrate the walls of a blood vessel, and can also disseminate the infection to other sites
Hyphae
A potent allergen and can cause severe bronchopulmonary reactions in atopic individuals and those heavily [occupationally] exposed
Aspergillus
We can treat aspergillus infections with
Amphotericin/fluorocytosine or one of the newer azoles
Even with treatment, mortality from aspergillus infection is
50-90%
