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Flashcards in Micro - Mycology Deck (48)
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1

Most fungal spores are _____ (sexual/asexual).

Asexual

2

Asexual fungal spores are also known as what?

Conidia

3

A gardener has an arm pustule with ascending lymphangitis. You biopsy it and see a fungus. What is it and how do you treat it?

Sporotrichosis ("rose gardener's disease") caused by Sporothrix schenckii; treatment is itraconazole or potassium iodide

4

A girl has hyperpigmented skin patches. You biopsy the skin and see "spaghetti and meatballs" on KOH prep. Diagnosis?

Tinea versicolor, caused by Malassezia furfur fungus

5

Name two systemic mycoses that are transmitted by inhalation of asexual spores.

Coccidioidomycosis and histoplasmosis

6

You see this fungus in the cerebrospinal fluid of an HIV-positive man with meningitis. What is it?

Candida albicans, yeasts with wide capsular halos that exhibit narrow-based budding

7

What do histoplasmosis, paracoccidioidomycosis, and blastomycosis have in common?

They are all systemic mycoses caused by dimorphic fungi (mold in soil, but yeast in tissue (remember: mold = cold; heat = yeast)

8

Histoplasmosis is endemic in what area of the United States?

The Mississippi and Ohio River valleys

9

Histoplasmosis is most commonly transmitted via what substance?

Bird or bat droppings

10

Blastomycosis is endemic in what areas of the United States?

The states east of the Mississippi River; it is also common in Central America

11

What is the characteristic microscopic appearance of blastomycosis?

Big, broad-based budding

12

A 40-year-old male from Central America presents with dyspnea and granulomatous skin nodules. What diagnosis do you expect?

Blastomycosis

13

Coccidioidomycosis is endemic in what area of the United States?

The southwestern United States, including California

14

What microscopic appearance distinguishes coccidioidomycosis from all other dimorphic fungi?

It is a spherule in tissue, not a yeast

15

What are two colloquial names for disease caused by coccidioidomycosis?

San Joaquin Valley fever and desert valley fever (desert bumps)

16

Paracoccidioidomycosis is endemic in what area?

Latin America

17

The yeast that causes paracoccidioidomycosis has what appearance on microscopy?

The "captains wheel" appearance

18

What is the treatment of choice for local infection with dimorphic fungi?

Fluconazole or ketoconazole

19

What is the treatment of choice for systemic infection with dimorphic fungi?

Amphotericin B

20

Systemic mycoses can mimic which other infectious disease with granuloma formation?

Tuberculosis

21

Histoplasmosis has what appearance under microscopy?

Macrophages filled with yeast (remember: Histo Hides in macrophages)

22

All systemic mycoses can cause what type of illness?

Pneumonia that can disseminate

23

In addition to pneumonia, what other illnesses can coccidioidomycosis cause?

Meningitis with dissemination to skin and bone

24

Describe the sizes of the four dimorphic fungi in relation to the size of a red blood cell.

Histoplasmosis: smaller; blastomycosis: same; coccidioidomycosis and paracoccidioidomycosis: larger

25

Tinea versicolor is caused by what organism?

Malassezia furfur

26

An athlete presents with hypopigmented macules on her upper back after a summer of exercising. What is your diagnosis and what is the treatment?

Tinea versicolor; treat with topical miconazole and selenium sulfide

27

What are the characteristic skin lesions of tinea pedis, cruris, corporis, and capitis?

Pruritic lesions with central clearing that resembles a ring (the infection is colloquially known as ringworm)

28

Tinea pedis, tinea cruris, tinea corporis, and tinea capitis are caused by what organisms?

Dermatophytes (ie, Microsporum, Trichophyton, Epidermophyton)

29

What animals are commonly reservoirs for Microsporum?

House pets

30

What is the typical microscopic appearance of the agent causing tinea versicolor on KOH prep?

"Spaghetti and meatballs" (Malassezia furfur)