Fungi Flashcards
How do yeasts multiply?
divide by binary fission or budding
What are Yeasts?
Single cell eukaryotes
What are molds?
Fungi that produce mycelia
Cellular composition of molds?
Multicellular
What is a hyphae?
A long branching filament that forms the feeding thallus of a fungus called the mycelium
What are the 2 types of hyphae?
Septate- walls that divide hyphae into cells
Aseptate-no walls
What are the 4 groups of Fungi?
Phycomycetes
Ascomycetes
Basidiomycetes
Deuteromycetes(fungi imperfecta)
What are phycomycetes?
1 Sexual spores are free zygotes
2 Asexual spores are enclosed in sac-like structure called sporangium
What about Ascomycetes?
1 Sexual spores enclosed in sacs called asci
2 Asexual spores are exogenous, formed at the end of the hyphae
What about Basidiomycetes?
Sexual spores found on basidia
What about Deuteromycetes?
(Fungi imperfecta) No sexual stage
What is a mycoses?
Disease caused by infection from a fungus?
Histoplasmosis is also know as?
Spelunker’s disease
What causes histoplasmosis?
Histoplasma capsulatum
Where is histoplasmosis found?
Found worldwide but concentrated in midwest and eastern US
What is histoplasmosis found in?
in soil contaminated with bat and bird feces(frequently in caves)
How do you get infected with histoplasmosis?
inhalation of the spores
What is another name for coccidiomycosis?
valley fever
What is coccidiomycosis caused by?
Coccidioides immitis
Where is coccidiomycosis found?
found in southwestern US (NM, AZ)
How do you get coccidiomycosis and what are the infections like?
Inhale arthrospore and most infections are asymptomatic, maybe only a slight fever
What is blastomycosis caused by?
blastomyces dermatitis
How do you get blastomycosis?
Spores are inhaled into lungs where they are transformed to a yeast form of the microbe
What are the symptoms of blastomycosis?
50% of individuals are symptomatic, with flu like illness with productive cough
How do you treat systemic fungi?
Amphotericin B- binds to sterols, and disrupts cell, which causes cell lysis
What is the one subcutaneous mycoses we need to know?
Sporotrichosis
What is sporotrichosis also known as?
rose handlers disease
what causes sporotrichosis?
sporothrix schenckii
who is susceptible to sporotrichosis?
occupational hazard for green house workers and gardeners
How do we become infected by sporotrichosis?
it enters through a skin lesion and transforms to a yeast form
How does sporotrichosis appear in the body?
as nodules and skin lesions that appear along the lymphatic system
How does dermatophytoses invade us?
through dead keratinized tissue(hair and nails)
What are the three major genera of dermatophytoses?
trichophyton, microsporum, epidermophyton
what is synonymous with dermatophytoses?
tinea
what is a tinea infection?
name given to a skin fungal infection
What are the 4 types of tinea infections and where on the body are they?
tinea pedis-athletes foot
tinea corporis-trunk or extremities
tinea capitis- heada, causes hair loss
tinea unguium- nails
what is the superficial mycoses called?
tinea versicolor
what causes tinea versicolor?
yeast
What causes tinea versicolor to proliferate?
it is caused by yeast which is part of the normal flora but heat humidity and sweat help it to proliferate
Is tinea versicolor contagious?
no
How to check for tinea versicolor?
1 use a KOH wet mount to look for yeast cells(it is a skin test)
2 use a woods lamp the black light will make an infected area fluoresce, normally the skin does not does not fluoresce or shine under UV light
What are two types of pathogenic yeast?
Candidiasis and cryptococcosis
What causes candidiasis?
caused by Candida albicans
Who gets Candidiasis?
it is part of the normal flora in the mouth, gut, and vagina. It becomes a pathogen when normal conditions are altered-antibiotics or depressed immunity
What does candidiasis look like?
thrush or skin infections
What causes cryptococcosis and what does it look like?
it is caused by cryptococcus neoformans and is a large encapsulated yeast
how do we get cryptococcus?
microbe enters the host via the respiratory route
What does cryptococcus do once you are infected with it?
after some time in the lungs it spreads to extra-pulmonary tissues
what does cryptococcosis have a predilection for(like)?
the brain so infected persons usually contact meningoecephalitis
What is Pneumocystis carinii?
maybe a fungus or a protozoan. different antigenic strains have been found in various animal hosts.
What does Pneumocystis Carnii do to someone?
it is an asymptomatic infectio of the lungs in early life and persists in an inactive or latent stage unless the host becomes immunocompromised
