Micro: Fungal and Parasites

Question 1

Name the 4 dimorph fungi.

Answer 1

Can Have Both Shapes

• Coccidiodes
• Histoplasma
• Blastomyces
• Sporothrix

Question 2

How are the dimorphs differentiated from one another?

Answer 2

unique characteristics of yeast form.

respiratory symptoms are very similar between all dimorphs

Question 3

Geography of Coccidiodes immitis.

Answer 3

Desert Southwest of U.S.

Question 4

Characteristic yeast form of C. immitis.

Answer 4

Spherule

Question 5

What lab test differentiates fungi and parasites from other microbes?

Answer 5

KOH prep

Question 6

Treatments and MOA for fungal infections.

Answer 6

Azoles (Fluconazole) is primary medication
-prevents synthesis of ergosterol

Amphotercin B: used in severe acute cases and pregnant patients because azoles are Teratogenic
-targets ergosterol creating a pore in the cell wall of fungal cells

Question 7

Characteric yeast form of Blastomyces dermatitidis.

Answer 7

Broad Based Budding yeast

Question 8

Pathogenesis of Histoplasma capsulatum.

Answer 8

Intracellular yeast: infects macrophages and plasma cells

Question 9

Source of Histoplasma.

Answer 9

Bird and bat dung

-spelunking in caves

Question 10

“Pilot’s Wheel” budding yeast.

Answer 10

Paracoccidiodomycosis

Paracoccidiodes brasiliensis

Question 11

Acute Angle budding hyphae in yeast

Answer 11

Aspergillus sp.

Question 12

Presentation of a patient with Farmer’s Lung and Tx.

Answer 12

Dry cough and chest tightness that occurs over and over again. Symptoms regress when taken away from offending agent. Alergic Aspergillosis sp. is a common cause.

Tx: for any Allergic Aspergillosis use oral corticosteroids

Question 13

Pathogenesis and Tx for Non-invasive Aspergillosis.

Answer 13

Fungus grows in a cavity in the lungs (fungal ball or aspergilloma). Only occurs after some other disease has occurred: TB, CF, chronic bronchitis.

Tx: surgical excision

Question 14

Risk factors for invasive Aspergillosis.

Answer 14

IC patients: transplant, leukemia, lymphoma, AIDS, corticosteroid therapy.

Question 15

Tx for invasive Aspergillosis

Answer 15

Voriconazole

Question 16

Disease caused by Zygomycosis sp. and characteristic of yeast for diagnosis.

Answer 16

Mucor

-90 degree branched hyphae

Question 17

Population most at risk for Mucor and unique clinical presentation.

Answer 17

Ketoacidotic Diabetics

-black pus from eyes, nose, and mouth

Question 18

Tx for Mucor.

Answer 18

Amphotercin B

Question 19

1 AIDS associated infection.

Answer 19

Pneumocystis jiroveci

-presents as atypical pneumonia

Question 20

How does Pneumocystis appear on Giemsa stain microscopy?

Answer 20

Dented Helmets

Question 21

Only lung parasite we need to know.

Answer 21

Paragonimus westermani (Lung Fluke)

Question 22

Intermediate host of the lung fluke.

Answer 22

Snail

Question 23

Presenting respiratory symptoms of lung fluke.

Answer 23

Rust colored sputum (or coffee ground sputum)

-often mistaken for TB

Question 24

How can a lung fluke be differentiated from TB?

Answer 24

Eggs found in sputum