Unit 4 - Yeasts

Question 1

What does Candida albicans cause?

Answer 1

candidiasis (other species can cause this as well)

Question 2

What is the morphology of Candida albicans?

Answer 2

rounded or oval budding cells - they may have fragments of pseudohyphae with buds attached in situ

Question 3

What does Candida albicans grow on?

Answer 3

SGA and others (BPA)

Question 4

What do colonies of Candida albicans look like?

Answer 4

they begin small but can enlarge - they are creamy, white with smooth edges and are very convex

Question 5

What four things is identification of Candida albicans based on?

Answer 5

1. Formation of pseudohyphae with typical blastospores 2. Production of thick walled terminal chlamydospores on rice infusion or cornmeal agar 3. Germ tube test or serum tube test: more common in human labs 4. Fermentation or assimilation of carbohydrates - necessary to speciate most yeasts

Question 6

Where does overgrowth of Candida albicans in poultry happen?

Answer 6

in the digestive tract

Question 7

Where do lesions from Candida albicans develop in poultry?

Answer 7

in the mouth, crop, proventriculus, and the gizzard

Question 8

What do lesions of Candida albicans look like?

Answer 8

whitish circular areas or elongated patches that may become confluent, slough, and leave ulcers

Question 9

In what population does epizootics do to Candida albicans occur in poultry?

Answer 9

it occurs in commercial poultry and are more serious in the young

Question 10

Candidiasis is a potential problem in pet birds on _______ _______.

Answer 10

antibiotic therapy

Question 11

What lesion does Candida albicans cause in cats and dogs?

Answer 11

occasional cutaneous infections especially in dogs with skin folds

Question 12

What does Candida albicans cause in cattle?

Answer 12

mastitis and abortion

Question 13

What is overgrowth of Candida albicans cased by in humans?

Answer 13

antibiotic and immunosuppresive therapies

Question 14

What lesions does Candida albicans cause in humans?

Answer 14

skin fold dermaitits, diaper rash, thrush, vulvovaginitis, intestinal infections, and occasional urinary and systemic infections

Question 15

What protects against systemic disease from Candida albicans?

Answer 15

antibody

Question 16

Is there immunization for Candida albicans?

Answer 16

yes, but it is not performed often

Question 17

How are poultry treated for a Candida albicans infection?

Answer 17

formic acid in the feed to reduce the number of organisms

Question 18

How are skin infections due to Candida albicans treated?

Answer 18

topical applications of Nystatin or clotrimazole

Question 19

What does Malassezia pachydermatitis cause?

Answer 19

canine and feline otitis externa

Question 20

What is the morphology of Malassezia pachydermatitis?

Answer 20

peanut shaped cells - bud on a broad base

Question 21

How does Malassezia pachydermatis grow?

Answer 21

good at 37 degrees C on BAP or SGA, small, strep-like colonies in 2-4 days

Question 22

What lesion does Malassezia pachydermatis cause?

Answer 22

yellowish deposits with a distinct yeast-like odor

Question 23

How do you diagnose Malassezia pachydermatis?

Answer 23

smear of the ear canal with gram stain

Question 24

How is Malassezia pachydermatis treated?

Answer 24

panolog and vinegar flushes

Question 25

what is Rhodotorula a normal inhabitant of?

Answer 25

moist skin

Question 26

What does Saccharomyces cervisiae cause?

Answer 26

thrush and vulvovaginitis

Question 27

What does Torulopsis glabrata cause?

Answer 27

Pyelonephritis, pneumonia

Question 28

What does Trichosporon cause?

Answer 28

superficial nodules on the distal portion of hair and opportunistic infections

Question 29

What does Rhinosporidium seeberi cause?

Answer 29

chronic infections of the nasal and ocular mucosa of humans, horses, mules, cattle and others

Question 30

What does Rhinosporidium seeberi infection lead to?

Answer 30

polyp formation

Question 31

What is the morphology of Rhinosporidium seeberi?

Answer 31

very small sporangia which are filled with thousands of spores - on cross section they look like white specks

Question 32

Where is Rhinosporidium seeberi endemic?

Answer 32

in India and Sri Lanka as well as sporadically in the southern US and other areas of the world

Question 33

What is infection with Rhinosporidium seeberi associated with?

Answer 33

water contact but this is not absolute

Question 34

What lesions are associated with Rhinosporidium seeberi infection?

Answer 34

fibromyxomatous polypoid lesions - there may be a mucopurulent nasal discharge and occasional lesions elsewhere on the body

Question 35

How is Rhinosporidium seeberi infection treated?

Answer 35

surgical removal and cautery at the base of the polyp

Question 36

What does Sporothrix schenckii cause?

Answer 36

sporotrichosis in equidae, humans, cattle, and others

Question 37

What is the morphology of Sporothrix schenckii classified as?

Answer 37

a dimorphic fungus

Question 38

What form of Sporothrix schenckii is found in tissues and in 37 C in the incubator?

Answer 38

the yeast form

Question 39

What does the yeast form of Sporothrix schenckii look like?

Answer 39

it looks elongated - forms cigar bodies

Question 40

What form of Sporothrix schenckii is found at 30 C?

Answer 40

mold

Question 41

What does the mold form of Sporothrix schenckii look like?

Answer 41

it produces fine, delicate, sepate, branching hyphae - conidia form at two sites of the hyphae

Question 42

What is the optimal growth environment for Sporothrix schenckii?

Answer 42

grow in SGA at 30 degrees C

Question 43

What do colonies of Sporothrix schenckii look like?

Answer 43

small whitish filamentous colonies which enlarge and darken with age

Question 44

What is the natural habitat of Sporothrix schenckii?

Answer 44

common saprophyte on dead plant material - conidia are common in the soil

Question 45

How does Sporothrix schenckii enter the body?

Answer 45

through skin wounds in the hands, feed, and head

Question 46

What is the most commonly infected species with Sporothrix schenckii?

Answer 46

horses and dogs

Question 47

What does Sporothrix schenckii cause in humans?

Answer 47

Rosegardener's disease

Question 48

What lesions does Sporothrix schenckii cause?

Answer 48

they start out as small reddish papules at the point of entry then spread via the lymphatic channels and form nodules. They ulcerate to the surface and exude a thick yellow pus

Question 49

What immunity is involved with Sporothrix schenckii?

Answer 49

humoral and cellular

Question 50

How is Sporothrix schenckii treated?

Answer 50

IV or oral sodium iodide in horses. Newer agents may be of value such as ketoconizole. Amphoteracin B is effective in humans

Question 51

True or False: Prototheca is not a fungus.

Answer 51

TRUE

Question 52

What are Prototheca?

Answer 52

green algae organisms that lack chlorophyll and are easily mistaken for bacterial or yeast colonies on blood agar plates

Question 53

Where is Prototheca found?

Answer 53

worldwide in sewage and soil

Question 54

What species is disseminated disease due to Prototheca associated with?

Answer 54

dogs

Question 55

What can Prototheca cause in cattle?

Answer 55

bovine mastitis and enteritis

Question 56

How is a Prototheca infecion treated?

Answer 56

its not - they are not susceptible to either antibiotics or antifungals

Question 57

What does Pseudogymnoascus (Geomuces) destructans cause?

Answer 57

white nose syndrome in hibernating bats

Question 58

Where is Pseudogymnoascus destructans present?

Answer 58

Eurasion countries, the Northeast US, and the midwest

Question 59

What is Pseudogymnoascus destructans spread by?

Answer 59

close contact - specifically by a mating orgy

Question 60

How does Pseudogymnoascus destructans infect bats?

Answer 60

it invades the skin and subcutaneous tissues of the nose and face and/or wing tissue

Question 61

What does Pseudogymnoascus destructans do to bats?

Answer 61

it causes them to have behavioral changes such as daytime flights in winter and moving towards the mouths of bat caves - the bats lose condition and eventually die

Question 62

Is there treatment for Pseudogymnoascus destructans?

Answer 62

antifungals have been used but success has notbeen reported

Question 63

What is another name for the Saprolegnia species?

Answer 63

cotton mold

Question 64

Why is Saprolegnia called cotton mold?

Answer 64

because they cause characteristic white or gray patches on fish

Question 65

How does Saprolegnia invade fish?

Answer 65

through damaged tissues or fish eggs and other freshwater species

Question 66

What is the pathogenesis of Saprolegnia infeciton?

Answer 66

1. Saprolegniasis is usually secondary to bacterial or viral infections in fish. 2. The organism apparenly attaches to damaged tissues via hooks on the tups of hair-like structures. 3. The fungus spreads across the surface of the host as a thin, cotton-like film. 4. It infects primarily the skin and gills but can occasionally infect superficial muscle tissues

Question 67

What can the lesion caused by Saprolegnia be mistaken for?

Answer 67

columnaris disease

Question 68

What is the end result of a Saprolegnia infection?

Answer 68

it is usually fatal as a result of hemodilution

Question 69

How is Saprolegnia prevented?

Answer 69

to maintain well-fed, healthy fish that are free of other diseases