Mycosis

Question 1

dimorphic fungi

Answer 1

two forms exist for one fungus species depending on temperature and conditions of environment

Question 2

2 forms of fungi

Answer 2

mycelial and yeast/yeast-like

Question 3

Dimorphic fungi capable of causing systemic infection

Answer 3

 Histoplasma capsulatum
 Blastomyces dermatitidis
 Coccidioides immitis
 Paracoccidioides brasiliensis
 Sporothrix schenckii

Question 4

Histoplasma capsulatum

Answer 4

-Associate with Bat guano (Spelunker) and bird
droppings
-Fungal Culture incubated at 30˚ C

Question 5

Histoplasmosis Disease

Answer 5

Reactivation disease can occur in elderly and
immunosuppressed (AIDS is a good example)
 Bone marrow exam is useful in diagnosing disseminated
infections
 Mucocutaneous lesions are common
and a site of dissemination

Question 6

yeast of Histoplasma capsulatum

Answer 6

prefer to
be intracellular and inhabit Macrophages.
Yeast are small 2 – 4 um, regular in size, and
oval to round. Yeast do not have a capsule,
this is just a staining artifact.

Question 7

Histoplasmosis rapid diagnosis

Answer 7

Antigen detection in urine
 Most useful for disseminated infection and chronic
pulmonary disease
 Antigen is detectable in >=85% of these infections
 Good for immune suppressed patients that do not
produce a detectable antibody response