Quick Review Cards for Medical Laboratory Science

Yeastcontinued Clinical Microbiology Review 272

YEAST INFECTIONS IMPORTANT CHARACTERISTICS OTHER

Malassezia furfur

Pneumocystis jiroveci

Yeasts can be identified by carbohydrate assimilation.

In skin infections, usually not cultured.

Identified by KOH prep of skin scrap-

ings. “Spaghetti & meatball” appear-

ance. In systemic infections, recovered

from blood cultures. Will only grow

on media overlaid with fatty acid,

e.g., sterile mineral or olive oil.

Can’t be cultured. Dx by histopatholog-

ical staining. Opportunistic infection in

AIDS & other immunocompromised

patients. Formerly P. carinii& classified

as a protozoan.

Tinea versicolor. Systemic

infection in children given

lipid replacement therapy

Atypical interstitial plasma

cell pneumonia (PCP)

Oval or bottle-shaped budding

yeast, 3–8 μm in diameter. Charac-

teristic collar between mother &

daughter cells. Chains of short,

slightly curved septate hyphae may

be seen in skin scrapings.

Cysts are 4–12 μm spheres with

intracystic bodies.