8.4-PNEUMOCYSTIS PNEUMONIA+PENICILLIOSIS+OTHER OPPORTUNISTIC MYCOSES

Question 1

What organism causes Pneumocystis pneumonia (PCP)?

Answer 1

Pneumocystis jiroveci (formerly P. carinii)

Question 2

What type of patients does P. jiroveci primarily affect?

Answer 2

Immunocompromised patients

Question 3

How common is dissemination of P. jiroveci?

Answer 3

Rare

Question 4

Before the AIDS epidemic, what was the main population affected by P. jiroveci?

Answer 4

Malnourished infants and immunosuppressed patients

Question 5

Before effective prophylaxis, what was a major cause of death in AIDS patients?

Answer 5

Pneumocystis pneumonia (PCP)

Question 6

What organs can P. jiroveci affect apart from the lungs?

Answer 6

Spleen, lymph nodes, bone marrow

Question 7

What are the major stages in the life cycle of P. jiroveci?

Answer 7

Trophozoite → Precyst → Cyst → Sporozoites → Trophozoites

Question 8

What is the function of trophozoites in P. jiroveci?

Answer 8

Feeding stage

Question 9

Is P. jiroveci an intracellular or extracellular pathogen?

Answer 9

Extracellular

Question 10

Where does P. jiroveci grow in the lung?

Answer 10

Surfactant layer above alveolar epithelium

Question 11

What are the two morphologically distinct forms of P. jiroveci?

Answer 11

Thin-walled trophozoites and thick-walled cysts

Question 12

What are the characteristics of the cysts?

Answer 12

Thick-walled, spherical to elliptical (4–6 µm), containing 4–8 nuclei

Question 13

What surface marker is found in P. jiroveci and can be detected in sera?

Answer 13

Surface glycoprotein

Question 14

What is the ideal specimen for diagnosing Pneumocystis pneumonia?

Answer 14

Bronchoalveolar lavage (BAL)

Question 15

What other specimens can be used?

Answer 15

Lung biopsy tissue, induced sputum

Question 16

What stains are appropriate for detecting P. jiroveci?

Answer 16

Giemsa, toluidine blue, methenamine silver, calcofluor white

Question 17

Can P. jiroveci be cultured?

Answer 17

No

Question 18

Does P. jiroveci cause disease in immunocompetent individuals?

Answer 18

No

Question 19

Has a natural reservoir for P. jiroveci been identified?

Answer 19

No

Question 20

What is known about the mode of infection for P. jiroveci?

Answer 20

Unclear

Question 21

When are most individuals infected with P. jiroveci?

Answer 21

Early childhood

Question 22

What is the global distribution of P. jiroveci?

Answer 22

Worldwide

Question 23

What type of immunity plays a dominant role in resistance to disease?

Answer 23

Cell-mediated immunity

Question 24

At what CD4 count does Pneumocystis pneumonia usually appear in AIDS patients?

Answer 24

Below 400 cells/µL

Question 25

What are the two main treatment options for Pneumocystis pneumonia?

Answer 25

Trimethoprim-sulfamethoxazole or pentamidine isethionate

Question 26

How can prophylaxis be achieved?

Answer 26

Daily trimethoprim-sulfamethoxazole or aerosolized pentamidine

Question 27

What organism causes Penicilliosis?

Answer 27

Penicillium marneffei (Talaromyces marneffei)

Question 28

What type of infection does P. marneffei cause?

Answer 28

Systemic infection in immunocompromised patients

Question 29

How has P. marneffei emerged as a pathogen?

Answer 29

As an endemic, opportunistic pathogen

Question 30

In which regions is P. marneffei endemic?

Answer 30

Southeast Asia, including China, Thailand, Vietnam, Indonesia, Hong Kong, Taiwan, Manipur (India)

Question 31

Where is P. marneffei commonly isolated from?

Answer 31

Soil, especially soil associated with bamboo rats and their habitats

Question 32

What is the colonial appearance of P. marneffei in mold form?

Answer 32

Green-yellow colony with diffusible reddish pigment

Question 33

What is the microscopic appearance of P. marneffei in mold form?

Answer 33

Septate, branching hyphae, brushlike aerial conidiospores, phialides, and basipetal chains of conidia

Question 34

What is the microscopic appearance of P. marneffei in tissue form?

Answer 34

Unicellular yeast-like cells (2 × 6 µm) dividing by fission

Question 35

What are the major risk factors for Penicilliosis?

Answer 35

HIV/AIDS, tuberculosis, corticosteroid treatment, lymphoproliferative diseases

Question 36

What are the clinical manifestations of Penicilliosis?

Answer 36

Fungemia, skin lesions, systemic involvement (especially reticuloendothelial system)

Question 37

What are the signs and symptoms of Penicilliosis?

Answer 37

Cough, fever, fatigue, weight loss, lymphadenopathy, cutaneous/subcutaneous papules or rashes

Question 38

What specimens are used for diagnosing Penicilliosis?

Answer 38

Skin, blood, or tissue biopsies

Question 39

How is Penicilliosis diagnosed?

Answer 39

Microscopic observation of yeast-like cells and positive cultures

Question 40

What is the treatment for Penicilliosis?

Answer 40

Amphotericin B (initial course), Itraconazole (follow-up therapy)

Question 41

What are opportunistic mycoses?

Answer 41

Globally distributed fungal infections with high incidence, severity, and mortality

Question 42

What innate host defenses protect against systemic candidiasis, invasive aspergillosis, and mucormycosis?

Answer 42

Neutrophils & monocytes

Question 43

What types of patients are at high risk for opportunistic mycoses?

Answer 43

Those with hematologic dyscrasias, immunosuppressive or cytotoxic drug treatment

Question 44

What fungal infections commonly affect HIV/AIDS patients?

Answer 44

Mucosal candidiasis (e.g., thrush, esophagitis)

Question 45

Which fungal infections occur in AIDS patients with CD4 counts <100 cells/µL?

Answer 45

Cryptococcosis, Pneumocystis pneumonia, Aspergillosis, Penicilliosis, Endemic mycoses

Question 46

Why is invasive aspergillosis or candidiasis difficult to diagnose?

Answer 46

Blood cultures are negative in aspergillosis, <50% positive in systemic candidiasis

Question 47

What is the key to successful management of opportunistic mycoses?

Answer 47

Early diagnosis, rapid antifungal therapy, control of underlying disease

Question 48

What diseases does Geotrichum candidum cause?

Answer 48

Pulmonary disease, wound infections, and oral thrush

Question 49

What is the key microscopic feature of Geotrichum candidum?

Answer 49

Abundant arthroconidia due to fragmentation of hyphae

Question 50

What disease is Fusarium commonly associated with?

Answer 50

Mycotic keratitis

Question 51

What is the distinctive microscopic feature of Fusarium?

Answer 51

Banana- or canoe-shaped macroconidia clustered in mats (sporodochia)

Question 52

What is unique about Fusarium macroconidia?

Answer 52

Only mycoses with banana-/canoe-shaped macroconidia

Question 53

What are the colony colors of Fusarium?

Answer 53

Rose, mauve, purple, yellow

Question 54

What are opportunistic mycoses?

Answer 54

Globally distributed fungal infections that cause high morbidity and mortality in immunocompromised patients

Question 55

Which mycoses have the highest incidence, severity, and mortality?

Answer 55

Systemic opportunistic mycoses

Question 56

What innate host defenses protect against systemic opportunistic mycoses?

Answer 56

Neutrophils & monocytes

Question 57

What part of the immune system plays an additional role in defense?

Answer 57

Adaptive immune response, particularly cell-mediated immunity

Question 58

What patients are at high risk for opportunistic mycoses?

Answer 58

Patients with hematologic dyscrasias (e.g., leukemia, anemia) and immunosuppressive or cytotoxic drug treatment

Question 59

What fungal infection is common in most HIV/AIDS patients?

Answer 59

Mucosal candidiasis (thrush, esophagitis)

Question 60

Patients with CD4 counts <100 cells/µL are at risk for what infections?

Answer 60

Cryptococcosis, Pneumocystis pneumonia, Aspergillosis, Penicilliosis, Endemic mycoses, Other opportunistic fungal infections