7.7 fungi / candida

Question 1

FUNGI –YEASTS

Answer 1

 Unicellular, round/oval
 Reproduce asexually by budding (some buds remain attached) or by
binary fission (rarely)
 Reproduce asexually via ascospores and basidiospores
 Colonies are moist, creamy, opaque or pasty

Question 2

FUNGI – MOLDS

Answer 2

 Multicellular
 Hyphae grow and intertwine to form a mycelium
 Colonies are fluffy, cottony, woolly, powdery

Question 3

CANDIDA ALBICANS

Answer 3

 Most common type of yeast
 Causes 75% of fungal infections in humans
 Normal flora: oropharynx, GIT, GUT, skin, upper respiratory tract
 Endemic in hospitals
 Infections are endogenous or nosocomial

Question 4

YEAST INFECTIONS

Answer 4

Paronychia
Thrush
Vulvovaginitis
Eye infections
Endocarditis
Meningitis
Fungemia and disseminated infections in immunocomp. pt.
Esophagitis in AIDS patients

Question 5

CANDIDA ALBICANS

Answer 5

 Most common yeast causing UTI
 Will grow on BA

Question 6

2 special fungal media

Answer 6

SAB: low pH and high glucose

IMA: antibiotics inhibit bacteria

Question 7

cnadida temp growth

Answer 7

28-30°C but will also grow at 35-37°C

think surface of body not internal

Question 8

CANDIDA ALBICANs how does it look

Answer 8

 Colonies are white, creamy, pasty, or waxy (some may be flat or dry
and can be starry)
 May have “yeasty” odour
 Gram positive round or oval, budding
 Some produce true hyphae / long spindles

Question 9

CANDIDA ALBICANS
pseudohyphae

Answer 9

 Most Candida spp. produce pseudohyphae
 Buds elongate, do not dissociate, and then form buds
 There are regular points of constriction
 Resemble sausage links

Question 10

GERM TUBE TESt

Answer 10

 A germ tube is an outpouching of the cell wall that becomes tubular and does not
have a constriction at its base (initial stage of true hyphae production)
 Specific to C. albicans
 Half as wide and 3-4X the length of the parent cell
 This test can differentiate C. albicans from other Candida sp.

circle and long tube

Question 11

GERM TUBE TEST METHOD

Answer 11

Suspend a small inoculum in sheep serum, fetal calf serum or rabbit plasma
 Incubate for 3 hours at 35-37°C
 Examine a wet prep for presence of germ tubes
 Positive: Candida albicans
 Negative: Candida spp

Question 12

CHLAMYDOSPORE PRODUCTION

jsut know test exists

Answer 12

Chlamydospores are round, thick-walled, swollen areas formed directly from
hyphae
 Test to identify Candida albicans
 Inoculate suspect organism to cornmeal agar and incubate at 30°C for 18-24 hours
 Look for production of chlamydospore