fungus........

Question 1

yeast reproduce by _______ (“blastoconidia”). What is the most common form of fungal infection?

Answer 1

yeast reproduce by budding. Candidiasis is the most common fungal infection

Question 2

What is a rapid grower in germ tubes, and what is another characteristic microscopic finding for this fungus

Answer 2

C. albicans grows in 2-4 hrs in a germ tube.

Has large, thick, usually single terminal chlamydospores

Question 3

pseudohyphae and blastoconidia suggest the genus _________. All of these spp. except for what produce pseudohyphae on a cornmeal agar

Answer 3

all suggest Candida spp

all Candida spp. except C. (Torulopsis) glabrata make pseudohyphae on cornmeal agar
- use RAT test to ID

Question 4

Geotrichum spp. are characterized by true hyphae that segment into rectangular _____________. They look like hockey sticks

Answer 4

arthroconidia

Question 5

C. parapsilosis colonies look like what?

Answer 5

spider or crossed matchstick

Question 6

“logs in stream” is the colony morphology for what kind of Candida spp.?

Answer 6

C. kefyr

Question 7

Saccharomyces spp. has characteristically roundish ______ (sexual spores in a sac) and are positive for what kind of stain?

Answer 7

Saccharomyces spp. has the round ascospores

pos for acid-fast stain

Question 8

Cryptococcus neoformans is uncharacteristically ______ pos, while most yeast are neg. It is also _____ ____ pos due to its capsules. Where is it most commonly found in nature?

Answer 8

urease pos, also india ink pos

found in bird and bat droppings

Question 9

C. neoformans has _____ oxidase, which can metabolize ____ ___ to melanin. What kind of agar is used for this fungus, and what color does this fungus have on this agar?

Answer 9

has phenol oxidase that can metabolize caffeic acid to melanin

it is red-brown pigmentation on bird-seed agar (which contains caffeic acid)

Question 10

C. neoformans can cause _______, which is very common to see in AIDS patients with this fungus

Answer 10

meningitis

Question 11

what kind of yeast is almost always associated with catheter infections?

Answer 11

Rhodotorula spp.
- pink on agar

Question 12

what are the three zygomycetes, and what else are they called due to their colony morphology? How can you tell them apart?

Answer 12

Rhizopus, Mucor, and Absidia are all “lid-lifters”

Rhizopus: rhizoids on bottom of sporangiophores

Mucor: no rhizoids

Absidia: rhizoids on side of sporangiophores
- can grow up to 45 C

Question 13

what diseases do the zygomycetes cause?

Answer 13

zygomycosis: infection of lungs, nasal sinuses, brain, eye, skin, ect

suppurative necrosis

Question 14

what is the most common cause of invasive disseminated aspergilliosis? What is included with this disease?

Answer 14

A. fumigatus
- fungus balls in lungs
- sinusitis
- respiratory infections!

grows well at 45 C

Question 15

A. niger don’t grow well at 45 C. What kind of infections does it most commonly cause?

Answer 15

ear infections

Question 16

what kind of mycotoxins does A. flavus cause?

Answer 16

aflatoxins

Question 17

Penecillium spp. turns ____-___ on an agar after first being white

Answer 17

blueish-green

Question 18

common plant pathogen with canoe-shaped conidia. White with pink/purple center

Answer 18

fusarium spp.

Question 19

what fungus has “brain” microscopic morphology? What kind of mycetoma does it cause?

Answer 19

Acremonium (also called “cephalosporum”) causes eumycotic white grain mycetoma

Question 20

Pityriasis (tinea) versicolor is caused by what fungus and requires what for growth? What are the characteristics of this disease?

Answer 20

caused by Malassezia furfur and needs olive oil overlay to grow

patchy lesions or scaling of varying pigmentation of chest/abdomen/trunk
- hypopigmentation = vitiligo

Question 21

Tinea nigra is caused by what fungus, and how is this disease characterized?

Answer 21

caused by Phaeoannelomyces (Exophiala) werneckii

characterized by hyperpigmentation
- brown to black non-scaly macules on palms and soles

Question 22

white piedra is caused by?

Answer 22

Trichosporon beigelii
- white to light brown soft nodules around beard and moustache hairs

Question 23

black piedra is caused by?

Answer 23

Piedraia hortae
- infection happens on scalp hair. black, hard gritty nodules

Question 24

the dermatophytes can all cause _____

Answer 24

ringworm

Question 25

microsporum spp. infects what two keratinized sources? What are the two spp. and how to tell the difference?

Answer 25

infect the hair and skin (but not nails) M. canis: macroconidia with pointed ends and bumpy surface M. gypseum: macroconidia with rounded ends and smoother surfaces (no hair projections)

Question 26

what is the fungus that have "comb-like" hyphae?

Answer 26

Microsporum audouinii

Question 27

Trichophyton spp. infects what keratinized sources?

Answer 27

skin, hair, and nails

Question 28

T. mentagrophytes is a common cause of _____ ____. What do the microconidia look like?

Answer 28

athlete's foot grapelike clusters (sometimes have thin macroconidia)

Question 29

T. rubrum usually infects what two keratinized sources? It is the most ____ dermatophyte to infect humans

Answer 29

skin and nailr (usually not the hair) most common infectious dermatophyte for humans

Question 30

T. tonsurans is the principle agent of _____. They have what shaped conidia?

Answer 30

causes scalp ringworm tear-drop shaped conidia on small trees/short stalks

Question 31

what trichophyton causes permanent hair loss?

Answer 31

T. schoenleinlii

Question 32

what fungus has "beaver-tail" macroconidia? What keratinized sources does it infect?

Answer 32

Epidermophyton floccosum infects the skin and nails only

Question 33

all dermatophytes except ________? are urease pos

Answer 33

T. rubrum is urease neg

Question 34

what three dermatophytes are hair perforation pos?

Answer 34

M. canis, M. gypseum, and **T. mentagrophytes**

Question 35

fungi are seen in tissue as ____ ____ in the disease of chromoblastomycosis. What does this infection cause?

Answer 35

in tissue as **sclerotic bodies** chronic infection of warty nodules, tumor-like masses, or raised, rough cauliflower-like lesions that have the sclerotic bodies

Question 36

what do you see in a mycetoma infection?

Answer 36

swollen, tumor-like lesions that yield **granular** pus through draining sinuses

Question 37

infecting agents occur in tissue as dark yeastlike cells/hyphae/pseudohyphae can cause _____________

Answer 37

phaeohyphomycosis

Question 38

what is the most common agent of chromoblastomycosis? What are it's four kind of conidiation?

Answer 38

Fonsecaea pedrosoi - fonsecaea - rhinocladiella - cladosporium - philophora

Question 39

what is the second most common cause of chromoblastomycosis? What kind of micro morphology does it have?

Answer 39

Phialophora verrucosa: vase shaped phialides with a flared cuplike collarette

Question 40

what is a common shower contaminant agent of chromoblasomycosis?

Answer 40

Cladosporium ("cladophialophora") spp - shield cells

Question 41

what is the spp. that look like pumpkin seeds microscopically?

Answer 41

cladophialophora carrionii

Question 42

what is an agent of phaeohyphomycosis that has a predilection for the brain?

Answer 42

Cladophialophora bantiana

Question 43

what agent of phaeohyphomycosis is one of the black yeasts and is KNO3 positive?

Answer 43

Exophiala jeanselmei

Question 44

what agent of phaeohyphomycosis has a predilection for the CNS (the brain and eye) and is KNO3 negative? What is its morphology? What test works well to grab this fungus?

Answer 44

Wangiella dermatitidis (exophiala dermatitidis) conidia like a catapult on hyphae tease prep works well

Question 45

what is a main agent of mycetoma that causes black grain mycetoma?

Answer 45

Madurella spp.

Question 46

what is called the "black killer mold" that produces several mycotoxins? Where is it commonly found?

Answer 46

Stachybotrys spp. is commonly found in water-damaged homes

Question 47

Scedosporium prolificans causes an invasive disease characterized by what two things? It's _________ have a swollen base and elongated necks (flask/lemon shaped)

Answer 47

arthritis and osteomyelitis annellides

Question 48

what kind of aerobic actinomyces is acid fast positive while all other kinds of aerobic actinomyces are AF neg? What is the most common spp. What color/texture colonies does it form? What does it smell like, and what other test is it pos for?

Answer 48

Nocardia (asteroides) is the most common kind of nocardia, which is AF pos. This spp. is orange and crumbly/crusty smells like dirt and is urease pos

Question 49

how to differ Streptomyces from Nocardia since they're both gram pos bacilli/cocci

Answer 49

Streptomyces is acid fast neg (blue)

Question 50

decomposition agars for nocardia include what three quadrants?

Answer 50

casein, xanthine, tyrosine

Question 51

what are the six dimorphic fungi that can cause serious mycoses?

Answer 51

1. cryptococcus neoformans - has capsule seen in India ink stain 2. Blastomyces dermatitidis - lollipop mold - broad base yeast 3. sporothrix schenckii - flower mold - cigar bodies yeast 4. histoplasma capsulatum - circular knobby mold 5. Paracoccidioides brasiliensis - mariner's wheel yeast 6. coccidioides spp. (eg. imminis) - barrel-shaped arthroconidia mold - spherules in tissue