[2] Microbiology of Fungi and Opportunistic Pathogens

Question 1

Distribution of Candida spp.

Answer 1

Saprophytes in Humans nad Animals

Question 2

Candida exists in what form in body tissue?

Answer 2

Yeast and Mold Form (Pseudohyphae)

Question 3

What is the typical agar used to culture Candida?

Answer 3

Sabaroud Dextrose Agar

Question 4

Color of Candida colonies?

Answer 4

White to Cream Colored with a smooth, waxy surface

Question 5

[Treatment]

Candida: Superficial Infections

Answer 5

Topical nystatin and Azoles

Question 6

[Treatment]

Candida albicans

Answer 6

Oral Fluconazole

Question 7

[Treatment]

Candida: other groups

Answer 7

Amphotericin B

Question 8

Important feature to distinguish Cryptocococcus gattii from C. neoformans

Answer 8

Formation of Cryptococcomas
Higher mortality
Longer treatment period

Question 9

Cryptocococcus neoformans is usually found in?

Answer 9

Pigeon droppings

Question 10

Cryptocococcus gattii is usually found in?

Answer 10

Eucalyptus trees (but is found worldwide, go figure)

Question 11

Pathway of Pathogenesis of Cryptococcus

Answer 11

Inhaled Yeast -> Primary Pulmonary Infection -> Asymptomatic Dormant -> Brain (Most common site of dissemination)

Question 12

[Characteristics]

Cryptococcus

Answer 12

Encapsulated, yeast-like

Reproduce by budding

Question 13

[Laboratory Diagnosis: Microscopic Examination]

Cryptococcus

Answer 13

India Ink Mount

Question 14

[Laboratory Diagnosis: Culture]

Cryptococcus

Answer 14

Sabouraud Agar without Cyclohexidine (it can kill the organism and prevent growth)

Question 15

[Laboratory Diagnosis: Definitive Test]

Cryptococcus

Answer 15

(+) CSF Culture

Question 16

[Treatment]

Cryptococcus: Mild to Moderate CNS Infections

Answer 16

Fluconazole

Question 17

[Treatment]

Cryptococcus: Meningitis

Answer 17

Amphotericin B in combination with Flucytosine or Fluconazole

Question 18

Most common species of Aspergillus causing invasive disease

Answer 18

Aspergillus fumigates

Aspergillus flavus

Question 19

Most common species of Aspergillus causing allergic disease

Answer 19

Aspergillus fumigates

Aspergillus clavatus

Question 20

Most common route of infection of Aspergillus

Answer 20

Respiratory Tract (Paranasal Sinus and Lungs)

Question 21

Species of Aspergillus linked to production of aflatoxin

Answer 21

Aspergillus flavus (Commonly found in peanuts)

Question 22

[Identify]

Septate hyphae
Dichotomous hyphae
Spores
Acute angle branching

Answer 22

Aspergillus

Question 23

[Laboratory Diagnosis: Microscopic Examination]

Aspergillus

Answer 23

10% KOH and Parker Ink

Question 24

[Laboratory Diagnosis: Culture]

Aspergillus

Answer 24

Sabouraud Agar

Question 25

[Laboratory Diagnosis: Serology] Aspergillus: Allergy

Answer 25

Detection of specific IgE in Serum: RAST

Question 26

[Laboratory Diagnosis: Serology] Aspergillus: Invasive Infection

Answer 26

Detection of Galactomannan Antigen in Serum: ELISA

Question 27

Etiologic Agents of Systemic Zygomycosis (Mucormycosis)

Answer 27

Zygomycetes

Question 28

[Laboratory Diagnosis: Microscopic Examination] Zygomycetes

Answer 28

10% KOH

Question 29

[Identify] Broad, irregularly shaped, non-septated Hyphae Right angle branching

Answer 29

Zygomycetes

Question 30

[Laboratory Diagnosis: Culture] Zygomycetes

Answer 30

Sabouraud's Agar without Cyclohexamide

Question 31

[Treatment] Zygomycetes

Answer 31

Surgery + Antifungals 1. Drainage and debridement 2. Amphotericin B

Question 32

Most common opportunistic mycoses in HIV

Answer 32

Pneumocystis carinii

Question 33

Most common fungal meningitis in HIV

Answer 33

Cryptococcosis

Question 34

[Laboratory Diagnosis: Culture] Pneumocystis carinii

Answer 34

Has not yet been cultured in labs

Question 35

3 Distinct Morphologic Stages of Pneumocystis carinii

Answer 35

Trophozoite Sporozoite Cyst

Question 36

[Pathogenesis] Pneumocystis carinii

Answer 36

Inhaled spores are deposited in alveoli -> Increase in number -> Pneumocystis carinii Pneumonia -> Acute Respiratory Distress Syndrome

Question 37

[Treatment] Pneumocystis carinii

Answer 37

Trimethoprim

Question 38

[Identification] Dichotomous septate hyphae Asexual fruiting structure

Answer 38

Aspergillosis

Question 39

[Identification] India Ink: Encapsulated Yeast

Answer 39

Cryptococcus

Question 40

[Identification] Budding yeast Septate hyphae Pseudohyphae

Answer 40

Candida