Systemic Mycoses

Question 1

What are the types of opportunistic pathogens that cause systemic mycoses?

Answer 1

1) Candida–>most common (yeast)
2) Cryptococcus neoformans (yeast)
3) Aspergillus (mold)
4) Pneumocystis jiroveci

Question 2

What type of pathogen can become an opportunistic pathogen?

Answer 2

Zygomycetes

Question 3

What are the species of Candida?

Answer 3

1) Candida albicans
2) C.tropicalis
3) C. parapsilosis
4) C. glabrata (cannot form pseudohyphae or true hyphae)

Question 4

Which species of Candida cannot form pseudohyphae or true hyphae?

Answer 4

C. glabrata

Question 5

What is used to differentiate C. albicans from all other yeasts?

Answer 5

Germ tubes that are formed at normal body temp (37 celcius)

Question 6

What medium is used to identify Candida species?

Answer 6

Chrome agar

Question 7

Candida Epidemiology

Answer 7

• Grows everywhere
• Major source of nosocomial infections
• Grows very well on plastics

Question 8

Candida Risk Factors

Answer 8

• Hematological malignancy
• Neutropenia
• GI surgery
• Extremes of age
• Exposures

Question 9

Candida Pathogenesis

Answer 9

Use adhesins like Fibronectin to attach to the cell surface and then use proteases that sit on hyphae and germ tubes to burrow inside

Question 10

Immunity to Candida

Answer 10

Neutrophils and a working Th1 response is critical

Question 11

What are some clinical manifestations of Candida?

Answer 11

• Diaper Rash
• Oropharyngeal Infection (Thrush)
• Vulvovaginitis (Yeast infection)
• Cutaneous disease…can affect scrotum, nails, in between digits

Question 12

How would you treat a mucosal or cutaneous Candida infection?

Answer 12

Topical nystatin or oral azoles

Question 13

How would you treat a deep-seated Candida infection?

Answer 13

Oral or IV azoles or Echinocandin

Question 14

How would you treat C. galbrata?

Answer 14

Amphotericin B plus Echinocandin

-It is resistant to Azoles

Question 15

What are the species of Aspergillus?

Answer 15

1) Flavus
2) Niger
3) Terreus

Question 16

What kind of patients are highly susceptible to Aspergillus infections?

Answer 16

Patients with previous lung problems.

Question 17

What are the species of Zygomyces?

Answer 17

1) Rhizopus

2) Mucor

Question 18

Zygomyces Morphology

Answer 18

Asexual conidia found within sporangium
Sparsely septated hyphae
-Rhizoids are present

Question 19

Which species of Rhizopus is the most common cause of human disease?

Answer 19

Rhizopus arrhizus

Question 20

What are the zygomycoses mentioned in class?

Answer 20

Rhinocerebral zygomycoses, Pulmonary zygomycoses, cutaneous zygomycoses

Question 21

What is the major organism that causes Pneumocystosis?

Answer 21

Pneumocystis jiroveci

Question 22

What can Pneumocystis jiroveci cause?

Answer 22

• Pneumocystis jiroveci pneumonia (PJP)
• Penumocystis carinii pneumonia (PCP)
• Interstitial pneumonitis

Question 23

How is Pneumocystosis diagnosed?

Answer 23

“Crushed Ping-Pong balls”

Question 24

How is Pneumocystosis treated?

Answer 24

Trimethoprim-Sulfamethoxazole (Anti-biotic)

Pentamidine (anti-parasitic)

Question 25

Morphology of Cryptococcus neoformans

Answer 25

Budding from a narrow/thin base

Question 26

Cryptococcus neoformans is associated with...

Answer 26

Soil contaminated by pigeons

Question 27

Cryptococcus gatti is found...

Answer 27

In the Pacific Northwest, associated with trees

Question 28

In immunocompromised patients, C. neoformans and C. gatti cause what disease?

Answer 28

Meningo-encephalitis. Results in increased intracranial pressure. Will be a chronic infection, and symptoms may wax and wane.

Question 29

Endemic fungi are of what morphology?

Answer 29

Dimorphic

Question 30

Endemic fungi are often found in...

Answer 30

soil and bat feces

Question 31

What is the morphology of Histoplasma capsulatum

Answer 31

Thermally dimorphic Room temp: Mold with thick-walled macroconidia and oval microcinidia Body temp (37 C): Intracellular thin-walled yeast

Question 32

Pathology of Histoplasma capsulatum

Answer 32

Microconidia are phagocytosed by macrophages and it germinates into yeast

Question 33

What regions is Histoplasma capsulatum endemic to?

Answer 33

Ohio and Mississippi river valleys, Mexico, Central and South America

Question 34

Symptoms of Histoplasmosis

Answer 34

Light antigen load--> no symptoms Heavy antigen load--> Flu-like symptoms Rare complications: ARDS, mediastinal fibrosis, pericarditis, arthritis

Question 35

1/100,000 people infected with Histoplasma capsulatum get?

Answer 35

Chronic pulmonary disease

Question 36

1/2,000 people infected with Histoplasma capsulatum get?

Answer 36

Disseminated infection. Chronic: weight loss, fatigue, oral ulcers, hepatosplenomegaly Subacute: Same as chronic but with fever, CNS probs, adrenals and heart valves Acute: Septic shock-like syndrome, oral&GI bleeding, meningitis, endocarditis

Question 37

Diagnosis of Histoplasma capsulatum

Answer 37

Serological test for histoplasmin antigen in serum or urine

Question 38

Treatment of Histoplasma capsulatum

Answer 38

Oral azoles and Amphotericin B..especially for chronic disseminated disease

Question 39

What is the morphology of Blastomyces Dermatitidis?

Answer 39

Room temp: White to tan mold with oval conidia found on terminal hyphae branches Body temp: Non-encapsulated yeast

Question 40

What is the distinctive feature of Blastomyces?

Answer 40

Broad-based budding

Question 41

Where is Blastomyces Dermatitidis found?

Answer 41

MS and Ohio River Valleys and Bogalusa, Louisiana | Conidia breathed in when soil and leaves are disturbed

Question 42

What are the symptoms of Pulmonary Blastomyces?

Answer 42

Acute: Spectrum of symptoms Chronic: Resembles cancer or TB

Question 43

What are the symptoms of Cutaneous Blastomyces?

Answer 43

Painless lesions that can resemble a squamous cell carcinoma in the skin and bones

Question 44

How do you diagnose Blastomyces Dermatitidis?

Answer 44

Broad-based budding in the tissue | Immunological test to look for antibodies

Question 45

Treatment for Blastomyces

Answer 45

Amphotericin B, Itraconazole, Fluconazole

Question 46

What is the morphology of Coccidiomycosis?

Answer 46

Room Temp: Barrel shaped arthrocondida | Body Temp: Anthrocondida become rounded spherules

Question 47

What is the epidemiology of Coccidiomycosis?

Answer 47

Endemic to SW USA, Northern Mexico, and South America | -Referred to as Valley Fever or San Joaquin Fever

Question 48

What kinds of infections do people with Coccidiomycoses get?

Answer 48

Primary infection: Asymptomatic pulmonary disease. 10% develop macular rash. Secondary infection: Symptomatic after 6 wks. Nodular cavitary disease in the lungs. Resembles military TB or disseminated TB.

Question 49

What are the risk factors for Coccidiomycoses?

Answer 49

HIV+ men of Filipino, African-American, Native American, or HIspanic origen -Mortality is 90% without treatment

Question 50

Diagnosis for Coccidiomycoses

Answer 50

Endosporulating spherules in sputum, exudates, or tissue | Most commonly made via biopsy

Question 51

Treatment of Coccidiomycoses

Answer 51

Amphotericin B, Itraconazole, Ketoconazole