Yeasts Flashcards

Question

Cryptococcus species (4)

Answer 1

1. Neoformans 2. Gattii 3. Albidus 4. Laurentii

Answer 2

1. Furfur 2. Globosa 3. Sympodialis 4. Obtusa 5. Restricta

Answer 3

95% of all invasive Candida infections are caused by 5 species: 1. Albicans 2. Glabrata complex 3. Tropicalis 4. Parapsilosis 5. Pichia kudriavzevii (formerly Candida krusei)

Answer 4

1. Oral candidiasis (thrush) 2. Vaginal candidiasis 3. Cutaneous candidiasis 4. Onychomycosis 5. Bronchopulmonary 6. Urinary tract infection 7. Intestinal candidiasis 8. Systemic

Answer 5

Risk factors- infants or elderly, immunosuppressed (AIDS), transplant recipients leukemia, cancer, TB, diabetes oral contraceptives, antibacterial treatment

Answer 6

Pregnancy or diabetes. Needs to be isolated repeatedly

Answer 7

Red, inflamed patches that can be localized or disseminated. Yeast are isolated in large numbers. Risk factors- obese, alcoholic, profuse sweating

Answer 8

Candidiasis of nail

Answer 9

A secondary infection following antimicrobial therapy. Symptoms- irritating cough, mucoid sputum. Pneumonia is visible on x-ray

Answer 10

Follows antimicrobial therapy that suppresses normal flora. Stool culture has predominant yeast growth

Answer 11

Hematogenous spread of the fungus occurring in debilitated patients. Inoculation can occur by medical devices or break in the skin barrier. Complications of the infection include endocarditis, meningitis, brain abscess, sepsis. There is a 19-24% mortality rate

Answer 12

In is normal flora of the skin, mouth, vagina, and stool. It is also found in the environment in leaves, flowers, water, and soil

Answer 13

Most common cause of mycoses worldwide. Grows at 42-45 degrees Celsius and is germ tube positive

Answer 14

Macroscopic- colonies appear cream colored, pasty, smooth, colonies have feet. CHROMagar -light green to light bluish-green. Microscopic- single yeast, budding, pseudohyphae

Answer 15

Pseudohyphae, clusters of Blastoconidia, thick-walled terminal, single chlamydospores

Answer 16

Cause bloodstream, urogenital, lung and other infections. Difficult to treat, resistant to azole, reduced susceptibility to Amphotericin B. Echinocandins can be used for treatment.

Answer 17

There is only a small, single, oval budding yeast

Answer 18

Macroscopic- colonies are small, white to cream, pasty, and smooth Microscopic- single budding yeast (condida), there are no pseudohyphae

Answer 19

Found in immunocompromised people, similar to all other Candida species. It is problematic in leukemia patients and other cancer patients

Answer 20

Macroscopic- colonies are cream colored and the edges may be wrinkled. Appear metallic blue on CHROMagar. Microscopic- round to oval yeast cells

Answer 21

Oval blastospores may appear singly or in clusters located along the long pseudohyphae. Pseudohyphae branch abundantly, rare true hyphae

Answer 22

Found worldwide. It is frequently associated with HIV resulting infections and bloodstream infections in non-HIV immunocompromised patients. These fungi do not grow at 42-45 degrees Celsius and are germ tube positive

Answer 23

Macroscopic- colonies are white to cream, soft, and can be smooth or wrinkled. On CHROMagar, they appear dark green Microscopic- only blastoconidia

Answer 24

Branched pseudohyphae & true hyphae with Blastoconidia are present. Abundant chlamydoconidia includes single, pairs, chains, and clusters.

Answer 25

Hospital and nursing home acquired. Found in many body sites and fluids, including blood, urine, respiratory and abdominal specimens

Answer 26

These infections are very serious, they can cause significant bloodstream or brain infections that may lead to death. They are difficult to identify on automated systems since they can't be differentiated from other species- MALDI-TOF or DNA sequencing must be used for an accurate identification. Candida auris is germ tube negative and grows well at 40-42. It has multi-colored colonies on CHROMagar

Answer 27

Treatment is difficult since these fungi are resistant to many antifungals. Resistant to azoles, possible amphotericin B, 5FC, echinocandin resistance

Answer 28

Macroscopic- white to cream Microscopic- Blastoconidia (budding yeast), almost never forms pseudohyphae

Answer 29

Radiating pseudohyphae and scattered blastoconidia, producing what are known as “spider” colonies

Answer 30

Formerly Candida krusei- long, wavy, branched pseudohyphae with elongated to ovoid Blastoconidia, budding off in branches.

Answer 31

Pigeon roosts, fruit, milk, plants. Aerosolization and inhalation of pigeon excrement is thought to be the infection route

Answer 32

Tropical and subtropical regions. US/Canada (BC, Vancouver, Washington) – trees, soil, water, wood products. Caused by inhalation of spores from the environment

Answer 33

Inhibited by cyclohexamide, affects the immunocompromised especially HIV(meningitis). Causes CNS infections, lesions on the skin, in the lungs, and other organs. Primarily a pulmonary disease. Latex agglutination for detection of cryptococcal antigen simple, sensitive and reliable - detects 90% of all cryptococcal meningitis cases.

Answer 34

Inhibited by cyclohexamide, recent pathogen, affects immunocompetent individuals. The primary site of infection is the lungs, where it causing pneumonia. Dissemination to other organs, notably the central nervous system (CNS), causes meningoencephalitis or brain cryptococcomas. Increasingly found in immunocompromising conditions.

Answer 35

Both strains are identical. Colonies are cream then turn a tan color as they age. They are flat or heaped, mucoid and have smooth edges. Phenol oxidase positive, form brown to black colonies on bird seed or caffeic acid

Answer 36

The fungi are round, dark-walled, budding yeast. They produce capsules

Answer 37

Round, dark-walled budding yeast- no hyphae

Answer 38

Commonly isolated from humans, mammals, birds, wine, beer, fruits, trees, plants, olives, and soil. Common colonizer of mucosa surface, known as “baker’s” or “brewer’s” yeast

Answer 39

Non-pathogenic for immunocompetent, but RARE report of fungemia & aortic graft infection in immunocompetent. Severe immunosuppression causes mucosal and disseminated disease-pneumonia, endocarditis, liver abscess, fungemia, and sepsis

Answer 40

Rapid growth, mature in 3 days. Colonies - flat, smooth, moist, glistening or dull, cream to tannish color

Answer 41

Blastoconidia - unicellular, ellipsoid to elongate, multilateral budding is typical. Pseudohyphae, if present, are rudimentary, hyphae are absent

Answer 42

So far, none have been identified. In a case review of 3300 yeast infection of cancer patients, 19 were identified as S. cerevisiae. In another case review, of 138 systemic fungal infections over a 15 year period, only 2 identified as S. cerevisiae. It was found that strains recovered from infected immunocompromised hosts were more resistant to host oxidative stresses. Can cause mucosal and disseminated infection in significantly immunocompromised hosts.

Answer 43

Lipophilic yeast found on skin and body surfaces of humans and animals

Answer 44

Causes catheter-associated fungemia in neonates and adults receiving prolonged intravenous lipids. May also cause lung infections. Symptoms- tinea versicolor or pityriasis versicolor – multi-colored skin

Answer 45

Smooth, cream to yellowish brown, with age – dry, wrinkled and brittle

Answer 46

These fungi do not bud. They form phialides with small collarettes. Thick round to oval yeast-like cells in clusters, spaghetti and meatballs morphology

Answer 47

Hyphal elements rare, phialides

Answer 48

Nutritional requirements leads to pathogenesis- the organisms are unable to synthesize medium and long chain fatty acids. Patients receiving central-line mediated total parenteral nutrition supplementation can be at increased risk of infection. 10% of newborns in non-NICU colonized. Additionally, 80% of newborns in the NICU are colonized. There is an increased association with prematurity, immunocompromised people, prolonged antimicrobial use and prolonged hospital stay. Infection causes fever, respiratory distress, sepsis, and it most commonly causes superficial skin infections

Answer 49

M. furfur requires lipid supplementation for in vitro growth. Add olive oil to culture

Answer 50

Air, soil, lakes, ocean water, and dairy products. Colonizes plants, humans, other mammals

Answer 51

Opportunistic mycoses in AIDS or acute leukemia patients - meningitis, endocarditis, ventriculitis, peritonitis, endophthalmitis, central venous catheter-infections, fungemia

Answer 52

Rapid grower, smooth, glistening, mucoid - cream to pink, coral red, orange or yellow colonies

Answer 53

Blastoconidia- unicellular, elongate in shape, may be encapsulated. Pseudohyphae and hyphae are absent

Answer 54

Worldwide - soil, water, air, sewage, plants, cereals, and dairy products. They are normal human flora from sputum and feces, colonizer GI tract

Answer 55

Opportunistic infections (inhalation or ingestion) = geotrichosis. Causes bronchial, pulmonary, disseminated infections, and infections from trauma

Answer 56

Rapidly growth, white, dry, powdery to cottony colony, resembling “ground glass.” When disturbed on the surface, the colony becomes yeast-like or slimy. The optimal growth 25°C, most strains = NG or weak growth at 37°C

Answer 57

Arthroconidia and coarse true hyphae are observed. Formation of arthroconidia and absence of empty cells that fragment to release arthroconidia (“disjunctor cells”) are typical. Blastoconidia, conidiophores, pseudohyphae = absent.

Answer 58

Found in soil, water samples, vegetables, mammals, and birds. They are normal flora of the mouth, skin and nails

Answer 59

White Piedra – forms white nodules on the hair shaft. Causes superficial and deep disseminated infections in humans. At risk populations include neutropenic patients and immunocompromised individuals

Answer 60

Cream progresses to a yellow/gray color. Appears smooth at first, then wrinkled and powdery-like.

Answer 61

Oblong yeast cells

Answer 62

True hyphae, pseudohyphae with Blastoconidia singly or in short chains. Arthroconidia on older cultures

Answer 63

Chlamydospores are produced by many fungi and represent enlarged, thick-walled vegetative cells with varied forms and condensed cytoplasm

Answer 64

A fungal cell produced by budding

Answer 65

A spore that is formed from the hyphae by fragmentation. Microscopically, mature arthroconidia appear square, rectangular, or barrel-shaped with thick walls.

Yeasts Flashcards

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