Yeasts Flashcards
Under a microscope, you see Hyphal structures. What is the causative agent? How would you describe the appearance?
- Mold
- “fuzzy”/wooly appearance
Under a microscope, you see Single cell/budding structures. What is the causative agent? How would you describe the appearance?
- Yeast
- “bacteria like”
List the representative yeasts.
Cryptococcus neoformans
Malassezia pachydermatis
Candida albicans
Cryptococcus neoformans is associated with ________ lesions affecting _______ membranes. Examples?
ulcerative, mucous
Respiratory tract (including nasal sinuses), central nervous system (meninges), eyes (chorioretinitis)
______ are more severely affected by Cryptococcus neoformans, resulting systemic mycosis.
Cats
How does Cryptococcus neoformans affect cattle?
- Cows (mastitis)
How does Cryptococcus neoformans affect horses?
- Horse (endometritis and abortion)
List all the species Cryptococcus neoformans affects?
Dogs, ferrets, sheep, goats, llamas, parrots, elk, horses, cats, cows, and humans
How does Cryptococcus neoformans affect humans?
(opportunistic pathogen/ immunocompromised patients)
Cryptococcus neoformans
Cryptococcus neoformans
Cryptococcus neoformans
* Characteristics
* ________ cells
* ____________ fungus
* Contains ____ acids- _____ complement proteins to degradation
* Produces phospholipase which is involved in the membrane _______ in the host cells
* Produces _________, a powerful antioxidant, resist enzyme ________, ______, allows _______ absorption
Spherical, Monomorphic, sialic, direct, disruption, melanin, degradation, radiation, nutrient
What is a major virulence factor of Cryptococcus neoformans? What is its purpose?
- It has a very thick capsule
Capsule, a major virulence factor. Prevents antibody phagocytosis, stimulate T regulatory cells,
inactivate the alternative complement pathway activation
Underline characteristics are associated with its pathogenesis in infected animals
Cryptococcus neoformans
* Growth characteristics
- _____ temperature to ___°C
- encapsulation is optimal in _________ agar plates, ___°C, ___% CO2
- produces _______ pigmented colonies
- four antigenic types: ?
room, 37, chocolate, 37, 5, melanin, A, B, C, D.
Cryptococcus neoformans
* Ecology
- lives in surface ____ and ___
- present in dried _____ feces up to _____ year (rich in _________)
dust, dirt, pigeon, one, creatinine
Cryptococcus neoformans
* Transmission
- respiratory, rarely percutaneous, non- contagiuos
What can be seen in the image below?
What can be seen in the image below?
Describe the pathogenesis of Cryptococcus neoformanns in the CNS.
Meningitis relatively asymptomatic), encephalitis, granuloma
Describe the pathogenesis of Cryptococcus neoformanns in the Pulmonary System
Bilateral, miliary lesions, lobar pneumonia
Describe the pathogenesis of Cryptococcus neoformanns in the cutaneous system
Traumatic implantation, ulcerative papules in skin
Nodules, granulomas, or ulcers in mucocutaneous tissue
Manifestation of systemic disease
What is the primary site of Cryptococcus neoformans infection in cats?
What is the primary site of Cryptococcus neoformans infection in dogs?
What is the primary site of Cryptococcus neoformans infection in horses?
What is the primary site of Cryptococcus neoformans infection in cattle?
What is the primary site of Cryptococcus neoformans infection in koala?
Cryptococcus neoformans - cat
Cryptococcus neoformans - cat
Cryptococcus neoformans - skin
Cryptococcus neoformans - lung
Cryptococcus neoformans - horse
Cryptococcus neoformans - dog
Cryptococcus neoformans
Immunity
- Serology: Detection of antibodies to ______
- _____ mediated immunity ( ________ activation)
- _____ cells
capsule, Cell, macrophage, NK
Cryptococcus neoformans
Laboratory Diagnosis
- ______ examination using _____ ink, from _______, _____________ washes, cerebro-spinal fluids
- Histopathology, _____ and _____ staining
- _________, ______ agar and _____ at room temperature or 30°C
Direct, india, exudates, tracheobronchial, Wright, Giemsa, Culture, blood, SDA
Cryptococcus neoformans
Treatment?
Control?
- Fluconazole, Itraconazole, 5- fluorocytosine
-Disinfect surfaces (facilities)
Malassezia pachydermatis
* Characteristics
- ____, ________ yeast
- ________ are not usually observed
- Culture in ____ agar, colonies with ______ tint seen on the surface
- Range of temperature incubation: ___ to ___°C
- ______ or _______
Oval, budding, Filaments, blood, greenish, 25, 41, Aerobic, microaerophilic
Malassezia pachydermatitis produces enzymes including?
How many biotypes does Malassezia pachydermatitis have? Name them.
proteinase, chondroitin sulfatase, hyaluronidase,
and phospholipase
- Four genetic biotypes: A, B, C, D.
What can be seen in this image?
Malassezia pachydermatidis
Malassezia pachydermatis normally lives on ___ and ____ _______ of dogs, cats, ferrets, ruminants, horses.
skin, ear canal
Malassezia pachydermatitis is associated with _____ ________ and _______.
otitis externa, dermatitis
What are the disease contributing factors that lead to Malassezia Pachydermatitis?
- Immune-mediated hypersensitivity and immunosuppression are
contributing disease factors
How is Malassezia pachydermatis transmitted? Which dog breeds are more susceptible?
Transmission
- Opportunistic fungus
- Associated to other skin diseases
- Dog breeds more susceptible: Australian silky terriers, basset hounds,
cocker spaniels, dachshunds, poodles, West highland white terriers.
Malassezia pachydermatis: Laboratory diagnosis
- _____ examination, ____-tipped swabs rolled on glass slides and stained with _____ and _____. You will see _____ with characteristic morphology of “ ______-shaped or “ _____ print”.
- Cotton-tipped swabs streaked on ____ at ____°C
- _____
Direct, cotton, Wright’s, Giemsa, yeast, bottled, shoe, SAD, 37, PCR
How is a case of Malassezia pachydermatis treated?
- Nystatin, clotrimazole, miconazole, ketoconazole, itraconazole
NICKM
What can be seen in the image below?
Malassezia pachydermatis
What can be seen in the image below?
Malassezia pachydermatis
What can be seen in the image below?
Malasseiza dermatitis associated with allergic dermatitis
Candida albicans (___________) is apart of ______ flora of mucous membranes of most ________ and ______
Candidiasis, normal, mammals, birds
How many species of Candida albicans exist? How many cause disease?
More than 200 species, few are associated with disease
Which species are more susceptible to infection by Candida albicans?
Immunocompromised animals (humans) are more susceptible & Overuse of antibiotics, steroids and hormones.
Candida albicans
* Oval budding yeast cells sprout _______ _____ that develop into _____-branching mycelium
* ___________
* Chlamydospore is a _____ walled _____ attached to the mycelium (in _____ only)
* _____ sero-groups are recognized: ?
germ tubes, septate, Blastoconidia, thick, sphere, vitro, Two, A and B
What can be seen in the image below?
What can be seen in the image below?
Pseudomycelium + blastoconidia
What are the cellular products produced by Candida albicans? What are their functions?
- Cellular products
- Adhesin: adhesion to extracellular matrix proteins
- Proteases and neuraminidases: promote tissue invasion and
adherence to host cells
Candida albicans
* Growth characteristics
- ________, ___ to ____°C, _____
Aerobic, 25, 30, SDA
Candida albicans
* Ecology
- Present in ____________ areas, ____ and _____ tracts of mammals and birds
mucocutaneous, GI, genital
How is Candida albicans transmitted?
- Transmission
- Endogenous infection, C. albicans is a commensal micro-organism
- Hematogenous spread Systemic infections
- List the characteristics of Candida albicans that help it carry out its disease pathogenesis.
- Candida albicans pathogenesis:
- Affects _______ surfaces of ____ tract from _____ to ____, ______ to ______ or ____ plaques with areas of _______ and ______ - What other areas are affected?
- Septicemic infections –> ?
- See below:
- Adhesin
- Cell wall glycoproteins –> Endotoxins
- Proteases and phospholipases –> virulence factors - mucous, GI, mouth, stomach, whitish, yellow, gray, ulceration, inflammation
- Genital tract, skin, claws are affected.
- Respiratory and intestinal
Candida albicans
Disease effects which species?
Birds, swine, equine, cattle, dogs, and cats
Candida albicans infection effects what part of the body in birds, swine, and equine?
GI tract
Candida albicans infection causes what conditions in cattle?
Pneumonic, enteric, mastitis, and systemic candidiasis
Candida albicans infection causes what conditions in dogs and cats?
non-healing ulcerative lesions on the oral,
upper respiratory mucosae, GI mucosae, and genitourinary tract
How would you diagnose Candida albicans in a patient?
- Laboratory diagnosis
- Blastoconidia, pseudohyphae observation
- Stains: Gram, Wright-Giemsa, periodic acid Shifft, Gomori metheneamine silver
How would you treat a patient suffering from Candida albicans ?
Candida albicans
How many species of Candida albicans exist? How many cause disease?
More than 200 species, few are associated with disease
Which species are more susceptible to infection by Candida albicans?
Immunocompromised animals (humans) are more susceptible & Overuse of antibiotics, steroids and hormones.