Dimorphic Fungi Flashcards Preview

Mycology > Dimorphic Fungi > Flashcards

Flashcards in Dimorphic Fungi Deck (42):
1

What makes a fungi "dimorphic"

Grow as a mold at 25-30C and in nature and grow as a yeast (or yeast-like or spherule) at 37C or in tissue

2

Who can be infected from dimorphic fungi?

"Normal" people

3

What is the infective stage of the fungi, mold or yeast?

mold stage

4

What tests can you run on a direct smear?

Giemsa, GMS, H&E, Gram stain, ect.

5

What temperature and plates do you use for molds?

25-30C usually on SAB, PDA, PFA

6

What temperature and plates do you use for yeasts?

37C usually on enriched media (BHI with blood)

7

Name the 6 Dimorphic Fungi

Sporothrix Schenckii
Histoplasma capsulatum
Blastomyces dermatitidis
Paracoccidioides brasiliensis
Penicillium marneffei

8

Sporotrichosis:
- Primary Clinical presentation

non-healing ulcer at inoculation site; finger, hand, arm, leg

9

Sporotrichosis:
- Secondary Clinical Presentation

linear series of nodules and draining ulcers along lymphatics
(pulmonary form is RARE)

10

Sporotrichosis:
- At Risk Occupations

Gardeners
Farmers
Florists
Horticulturists

11

Sporotrichosis:
- what plants cause infections

rose thorns and sphagnum moss

12

Sporotrichosis:
- Morphology of yeast

small, round or show the "cigar shape"

13

Sporotrichosis:
- Morphology of mold

septate hyphae with floweriness or rosettes of conidia

14

Histoplasmosis:
- At risk population and symptoms

Otherwise "healthy" people
- most habe asymptomatic infection
- may have calcification in lungs, liver, spleen

15

Histoplasmosis:
- clinical presentation in immune suppressed people

disseminated disease

16

Histoplasmosis:
- endemic area

Mississippi River Valley (Ohio River, Missouri River)

17

Histoplasmosis:
- What is it associated with?

soil enriched by droppings of blackbirds, chickens and bats (nitrogen content)
"Spelunker's disease", "Cave disease", "Darlings Disease"

18

Histoplasmosis:
- Should we skin test people from the midwest? Why or why not?

80-85% of people living in the midwest test positive for histoplasma skin test and show antibodies in their serum (so skin test is worthless)

19

Histoplasmosis:
- Yeast appearance

SMALL yeast inside monocytes or macrophages; usually in clumps; often gives a hint of "halo" but there is NO CAPSULE

20

Histoplasmosis:
- Mold appearance

shows spiked or "tuberculate" macroconidia

21

Histoplasmosis:
- Three available tests for diagnosis
- Which one is diagnostic in disseminated disease?

- Skin test
- Serum antibodies
- URINE ANTIGEN TEST (diagnostic)

22

Blastomycosis:
- Primary clinical presentation

Most asymptomatic; may progress to chronic pulmonary disease, cutaneous ulcers or pustules may mimic cancer!

23

Blastomycosis:
- Endemic area

States adjacent to Mississippi and Ohio rivers

24

Blastomycosis:
- Yeast appearance

BIG, thick cell wall, single bud with a BROAD BASE,

25

Blastomycosis:
- Mold appearance

Show microconidia on short conidiophores (lollipops)

26

Blastomycosis:
- Identification

Urine Antigen (EIA)

27

Paracoccidioidomycosis:
- Clinical presentation

Respiratory infection; ulcerative lesions of mouth, nose and GI; Dissemination in immunocompromised host

28

Paracoccidioidomycosis:
- Endemic area

Brazil and other countries in South America (high rainfall areas)

29

Paracoccidioidomycosis:
- Yeast appearance

large, with multiple daughter buds (Mariner's Wheel)

30

Paracoccidioidomycosis:
- Mold appearance

Small lollipops and septet hyphae; conidia are a smaller version of those seen in Blasomyces

31

Coccidioidomycosis:
- Seen in what type of people
- associated with what?

- Black and Filipino males
- Associated with dust storms; inhalation of arthroconidia from desert soil

32

Coccidioidomycosis:
- Endemic area

Desert southwest U.S. (California, Arizona, SW texas)

33

Coccidioidomycosis:
- What does a tissue biopsy show for this organism?

Spherules (contain bodies called endospores); can be empty, endospores can produce new spherules; TISSUE PHASE IS NOT A YEAST

34

Coccidioidomycosis:
- temperature mold will grow

25C and 37C

35

Coccidioidomycosis:
- mold appearance

alternately staining, barrel-shaped ARTHROCONIDIA

36

In Coccidioides immitis mold phase is highly ________

infectious

37

Coccidioidomycosis:
- Why are labs not allowed to keep cultures without special permission?

It is a bioterrorism alert!

38

Penicillium marneffei:
- pathogen or nonpathogen?

only real pathogen in penicillium family

39

Penicillium marneffei:
- Endemic area

SE Asia (AIDS patients)

40

Penicillium marneffei:
- Yeast appearance

may resemble Histoplasma

41

Penicillium marneffei:
- mold appearance

Green to reddish-green aerial hyphae

42

Penicillium marneffei:
- Colony morphology

RED DIFFUSIBLE PIGMENT