Unit 4 - Yeasts Flashcards
What does Candida albicans cause?
candidiasis (other species can cause this as well)
What is the morphology of Candida albicans?
rounded or oval budding cells - they may have fragments of pseudohyphae with buds attached in situ
What does Candida albicans grow on?
SGA and others (BPA)
What do colonies of Candida albicans look like?
they begin small but can enlarge - they are creamy, white with smooth edges and are very convex
What four things is identification of Candida albicans based on?
- 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
Where does overgrowth of Candida albicans in poultry happen?
in the digestive tract
Where do lesions from Candida albicans develop in poultry?
in the mouth, crop, proventriculus, and the gizzard
What do lesions of Candida albicans look like?
whitish circular areas or elongated patches that may become confluent, slough, and leave ulcers
In what population does epizootics do to Candida albicans occur in poultry?
it occurs in commercial poultry and are more serious in the young
Candidiasis is a potential problem in pet birds on _______ _______.
antibiotic therapy
What lesion does Candida albicans cause in cats and dogs?
occasional cutaneous infections especially in dogs with skin folds
What does Candida albicans cause in cattle?
mastitis and abortion
What is overgrowth of Candida albicans cased by in humans?
antibiotic and immunosuppresive therapies
What lesions does Candida albicans cause in humans?
skin fold dermaitits, diaper rash, thrush, vulvovaginitis, intestinal infections, and occasional urinary and systemic infections
What protects against systemic disease from Candida albicans?
antibody
Is there immunization for Candida albicans?
yes, but it is not performed often
How are poultry treated for a Candida albicans infection?
formic acid in the feed to reduce the number of organisms
How are skin infections due to Candida albicans treated?
topical applications of Nystatin or clotrimazole
What does Malassezia pachydermatitis cause?
canine and feline otitis externa
What is the morphology of Malassezia pachydermatitis?
peanut shaped cells - bud on a broad base
How does Malassezia pachydermatis grow?
good at 37 degrees C on BAP or SGA, small, strep-like colonies in 2-4 days
What lesion does Malassezia pachydermatis cause?
yellowish deposits with a distinct yeast-like odor
How do you diagnose Malassezia pachydermatis?
smear of the ear canal with gram stain
How is Malassezia pachydermatis treated?
panolog and vinegar flushes
what is Rhodotorula a normal inhabitant of?
moist skin
What does Saccharomyces cervisiae cause?
thrush and vulvovaginitis
What does Torulopsis glabrata cause?
Pyelonephritis, pneumonia
What does Trichosporon cause?
superficial nodules on the distal portion of hair and opportunistic infections
What does Rhinosporidium seeberi cause?
chronic infections of the nasal and ocular mucosa of humans, horses, mules, cattle and others
What does Rhinosporidium seeberi infection lead to?
polyp formation
What is the morphology of Rhinosporidium seeberi?
very small sporangia which are filled with thousands of spores - on cross section they look like white specks
Where is Rhinosporidium seeberi endemic?
in India and Sri Lanka as well as sporadically in the southern US and other areas of the world
What is infection with Rhinosporidium seeberi associated with?
water contact but this is not absolute
What lesions are associated with Rhinosporidium seeberi infection?
fibromyxomatous polypoid lesions - there may be a mucopurulent nasal discharge and occasional lesions elsewhere on the body
How is Rhinosporidium seeberi infection treated?
surgical removal and cautery at the base of the polyp
What does Sporothrix schenckii cause?
sporotrichosis in equidae, humans, cattle, and others
What is the morphology of Sporothrix schenckii classified as?
a dimorphic fungus
What form of Sporothrix schenckii is found in tissues and in 37 C in the incubator?
the yeast form
What does the yeast form of Sporothrix schenckii look like?
it looks elongated - forms cigar bodies
What form of Sporothrix schenckii is found at 30 C?
mold
What does the mold form of Sporothrix schenckii look like?
it produces fine, delicate, sepate, branching hyphae - conidia form at two sites of the hyphae
What is the optimal growth environment for Sporothrix schenckii?
grow in SGA at 30 degrees C
What do colonies of Sporothrix schenckii look like?
small whitish filamentous colonies which enlarge and darken with age
What is the natural habitat of Sporothrix schenckii?
common saprophyte on dead plant material - conidia are common in the soil
How does Sporothrix schenckii enter the body?
through skin wounds in the hands, feed, and head
What is the most commonly infected species with Sporothrix schenckii?
horses and dogs
What does Sporothrix schenckii cause in humans?
Rosegardener’s disease
What lesions does Sporothrix schenckii cause?
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
What immunity is involved with Sporothrix schenckii?
humoral and cellular
How is Sporothrix schenckii treated?
IV or oral sodium iodide in horses. Newer agents may be of value such as ketoconizole. Amphoteracin B is effective in humans
True or False: Prototheca is not a fungus.
TRUE
What are Prototheca?
green algae organisms that lack chlorophyll and are easily mistaken for bacterial or yeast colonies on blood agar plates
Where is Prototheca found?
worldwide in sewage and soil
What species is disseminated disease due to Prototheca associated with?
dogs
What can Prototheca cause in cattle?
bovine mastitis and enteritis
How is a Prototheca infecion treated?
its not - they are not susceptible to either antibiotics or antifungals
What does Pseudogymnoascus (Geomuces) destructans cause?
white nose syndrome in hibernating bats
Where is Pseudogymnoascus destructans present?
Eurasion countries, the Northeast US, and the midwest
What is Pseudogymnoascus destructans spread by?
close contact - specifically by a mating orgy
How does Pseudogymnoascus destructans infect bats?
it invades the skin and subcutaneous tissues of the nose and face and/or wing tissue
What does Pseudogymnoascus destructans do to bats?
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
Is there treatment for Pseudogymnoascus destructans?
antifungals have been used but success has notbeen reported
What is another name for the Saprolegnia species?
cotton mold
Why is Saprolegnia called cotton mold?
because they cause characteristic white or gray patches on fish
How does Saprolegnia invade fish?
through damaged tissues or fish eggs and other freshwater species
What is the pathogenesis of Saprolegnia infeciton?
- 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
What can the lesion caused by Saprolegnia be mistaken for?
columnaris disease
What is the end result of a Saprolegnia infection?
it is usually fatal as a result of hemodilution
How is Saprolegnia prevented?
to maintain well-fed, healthy fish that are free of other diseases
