Yeasts
Terms
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- What is the most common type of yeast genus?
- Candida
- what's the most important Candida?
- Candida albicans
- what type of infection does Candida albicans cause?
- ENDOGENOUS
- where is C. albicans normal flora?
- skin, intestine, mucous membranes
- what 2 diseases are charact. of C. albicans?
-
Thrush - in babies and Aids patients
Vaginitis - What is thrush?
- a yeast infection but in the mouth
- What other diseases are caused by C. albicans other than thrush and vaginitis?
-
Skin infections
Onychomycosis - nails
Pneumococcal pneumonia allows 2ndary inf.
Diaper rash - What are the colonies of C. albicans like?
- White, pasty and convex.
- what does C. albicans grow on?
- Sabdex
- what do colonies look like on BA of C. albicans? think hollywood
- starry because of hyphae growing out
- what test identifies C. albicans?
- Germ tube
- if the germ test for C. albicans is negative, what then?
- Corn meal agar
- what characteristics on Cornmeal agar identify C. albicans?
-
TERMINAL chlamydospores
pseudohyphae
yeast cells - if on corn meal agar all you see is yeast cells, what is the I.D.?
- YEAST SPECIES
- what identifies only Candida species in general?
- Pseudohyphae and yeast cells
- what's the first step in diagnosing whether you're dealing with C. albicans or a yeast?
- LPCB - lactol phenol cotton blue prep
- on the LPCB, what would make you do a germ tube test?
- seeing Pseudohyphae and yeast cells
- what is assimilation tube testing?
- tests for carbohydrates on yeast for further identification - not fermentation
- what is Cryptococcosis?
- an infection caused by inhalation of pigeon droppings - llatch really grossed out by it
- what is the pathogenic mechanism of cryptococcosis?
- it begins as a lung infection, disseminates to the brain/meninges.
-
what is the virulence factor of cryptococcus neoformans?
what does it cause again? -
a CAPSULE.
cryptococcosis - how id Cryptococcus neoformis identified?
- -Capsule stain
- what type of dye is used to i.d. cryptococcus neoformis?
- india ink - a capsule stain
- what specimen is used?
- CSF
-
what is the colonial mophology of cryptococcus neoformis?
what test is v. good id? -
pasty yeast colonies become mucoid and the colonies SAG. not usually seen in yeast.
Urea Positive - what used to be a parasite but now is a yeast?
- pneumocystis carinii, aka jiroveci
-
in rodents, Pneumocystis species is:
in humans? -
rodents = carinii
humans = jiroveci - what does Pneumocystis jiroveci/carinii cause?
- PCP - interstial Plasma Cell Pneumonia
- who is PCP often found in?
- Aids pateints
- what are the 4 symptoms of PCP?
-
-nonproductive cough
-Rapid respiration
-fever
-cyanosis - what is a good diagnostic characteristic of pneumocystis carinni?
- looks like punched in ping pong balls
- what are 3 types of specimens used for testing PCP? what is NOT used? What is best?
-
Bronchoalveolar lavage- best
open lung biopsy
bronchial brush
never sputum - what are 2 stains used for pcp id?
-
silver stain
immunoflourescent - is serology useful for PCP id?
- no; 2/3 of infants have antibody to it, and everybody else too
- how many cells are there per yeast?
- one - they are unicellular
- how do yeast reproduce?
- by budding
- what 3 types of people are yeast infections especially common in?
-
immunocompromised
people on broad-spec antibiots
people w/ indwelling catheters. - what are the 2 names of infections caused by C. albicans?
-
1. Candidiasis
2. Moniliasis - for yeasts OTHER than C. Albicans, what are the two broad categories of species (based on morphology)?
-
Blastoconidia
Arthroconidia -
blastoconidia are i.d. as:
arthroconidia are i.d. as: -
Blasto = Yeast sp. only
Arthro =
1. Blastoschizomyces
2. Geotrichum
3. Trichosporon -
What are Mucocutaneous yeast infections treated with?
(3 drugs) -
1. Nystatin
2. Clotrimazole
3. Ketoconazole - What are Systemic yeast infections treated with?
-
1. Amphotericin B
2. 5-Flourocytosine
3. Ketoconazole - lkj
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