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46 Cards in this Set

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Where are yeasts normal flora?
-Oral cavity
-Skin
-Intestine
-Vagina
So how do we often see yeasts in lab?
As Contaminants
As opportunistic infections
What specimens can yeast contaminate?
-Lower Resp tract
-Upper resp tract
-Genital culture
-Skin culture
-Urine culture
-Intestinal culture
Yeast isolated from what specimens would indicate a pathogenic infection?
-Blood, CSF, body fluids
-Tissues, abscess, urine, LRT
What is included in the lab workup of a yeast?
-Colonial morphology
-Microscopic morphology
-Germ tube
-Cornmeal agar
-API 20C/other automated
What types of agar are used to grow yeast?
-Sabdex
-Blood agar
-Chromagar
What is chromagar for?
Differentiating C. albicans
What chromagar colors are:
-C. tropicalis
-C. albicans
-C. glabrata/krusei
-C. parapsilosis
Tropic = blue
Albicans = aqua
Glabrata = pink
Parapsilosis = white
What are 4 methods for complete identification of yeasts?
-Assimilation sugars
-API 20C
-Automated systems
-Additional biochemicals
What 3 disease categories are associated w C. albicans?
1. Mucocutaneous
2. Cutaneuos
3. Systemic
What are 4 mucocutaneous infections of C. albicans?
1. Thrush
2. Vaginitis/balanitis
3. Bronchial/pulmonary
4. Intestinal
What causes intestinal mucocutaneous C. albicans infection?
Overuse of antibiotics
What temp is Corn meal agar incubated at?
MUST be 25'C; 30 can inhibit.
4 types of cutaneous C. albicans infections are:
1. Intertriginous
2. Diaper rash
3. Paronychia
4. Candida granuloma
What are 4 types of systemic C. albicans infections?
1. Urinary tract
2. Endocarditis
3. Meningitis
4. Septicemia
What is the more commonly isolated Candida sp from UTI?
C. albicans; then
Glabrata
tropicalis
What are some causes of disseminated candidiasis?
-Numerous intravasc. devices
-More immunocompromised pts
-Broadspectrum antibiotics
-Technology-assisted life support
What is a common oral thrush infection in AIDS patients?
Esophagitis
What do ALL candida species produce on corn meal agar?
-Yeast cells
-Pseudohyphae
-True hyphae
What does C. albicans produce to differentiate it?
-Terminal chlamydospores
What are some risk factors for disseminated candidiasis?
-Neutropenia
-Organ transplants
-Severe systemic diseases
-Heroin addiction
-GI surgery
What 3 common Antifungals are used for Candidiasis?
-Amphotericin B deoxycholate
-Azoles (flucon/posaconazole)
-Echinocandins
What should be kept in mind regarding antifungals?
C. albicans is developing resistance to the azoles
What cornmeal characteristics are unique to C. glabrata?
-Yeast cells
-NO hyphae
How does C. glabrata look on the API 20C?
Inactive;
ONLY GLU/TRE pos
What infections does C. glabrata typically cause?
-UTI
-Fungemia - esp in patients with solid tumors
What yeast is associatd with CNS disorders?
Cryptococcus neoformans
What other type of disease does it cause?
pulmonary cryptococcosis
What 4 methods are used for identifying c. neoformans?
-India ink prep
-Latex agglutionation
-Urea reaction
-Birdseed agar
What do the id methods show for c. neoformans?
India ink = capsule
Latex aggl = agglutination
Urea = pos
Birdseed = brown
What is the birdseed agar used to show again?
Caffeic acid in c. neoformans - it turns colonies brown on agar.
What is a common contaminant in research labs?
Rhodotorula
What is the identifying characteristic about Rhodotorula?
Red colonies, urea pos
When should amphotericin B be used as an antifungal?
only as a last resort; it's very hard on the kidneys.
how is c. neoformans transmitted?
PIGEON DUNG
What type of yeast is Blastoschizomyces?
Normal skin flora
Saprophyte
What infections does Blastoschizomyces cause?
-Onychomycosis
-Meningitis
-UTI
-Endocarditis
What type of morphology does blastoschizomyces have on agar?
-White/cream
-Mold-like
-Short arial hyphae
What characteristics are used to differentiate Blastoschizomyces on agar?
-Hyphae/pseudohyphae
-Annelloconidia
-Arthroconidia (some)
-Urea NEG
What do we differentiate Blastoschizomyces from?
-Trichosporon
-Geotrichum
What are id characterisitcs of trichosporon?
-Psudohyphe and Hyphae
-BLASTOCONIDIA
-NO annello
-UREA pos
What are id characteristics of geotrichum?
-Hyphae
-NO pseudohyphae
-LOTS of arthrospores
-no blasto/annello
-Urea neg
what is trichosporon known to cause?
white piedra
what is the beer/bread yeast?
saccharomyces cerevisiae
What a unique characteristic of S. cereviseae?
-Ascospores - sexual spores that stain acid fast.
What mold is a common cause of pneumonia in AIDS pts?
-Pneumocystis jiroveci