Systemic Fungi

Question 1

Histoplasmosis

Answer 1

Caused by Histoplasma capsulatum
Most common systemic fungal disease

Question 2

Histoplasma capsulatum Location

Answer 2

Ohio, Mississippi, and Missouri River valleys

Question 3

Histoplasma capsulatum Clinical manifestations

Answer 3

Pulmonary disease
Disseminated disease

Question 4

Histoplasma capsulatum Pulmonary disease

Answer 4

Present with mild flu-like symptoms
Small calcifications remain in lungs and affected lymph glands

Question 5

Histoplasma capsulatum Disseminated disease

Answer 5

Chronic form may develop immediately or years later
Results in systemic dissemination to other organs
Characterized by ulcerating sores in mouth and nose, enlargement of spleen, liver and lymph node and severe infiltration of the lungs

Question 6

Histoplasma capsulatum Colony Morphology

Answer 6

25-30 C - white to brown, pinkish, with fine dense cottony texture
Reverse: White or yellow

35-37 C - moist, white, yeast-like colonies. Inhibited by cycloheximide

Question 7

Histplasma capsulatum Microscopic

Answer 7

25-30 C (mold phase) - septate hyphae with short lateral conidiophores, spherical to oval to pyriform microconidia “lollipop” pattern

35-37 C (yeast phase) - 7-10 days. Demonstrate spherical to oval budding yeast cells.

Question 8

Blastomycosis

Answer 8

Called Gilchrist’s Disease
Caused by Blastomyces dermatitidis
Usually only affects the skin but may invade the lungs, kidneys, CNS, and bones

Question 9

Blastomyces dermatitidis Location

Answer 9

Ohio, Mississippi, and Missouri River vally

Question 10

Blastomyces dermatitidis Clinical Manifestations

Answer 10

1) Respiratory infection acquired through inhalation
2) Chronic form may involve one or more organs - commonly lungs and followed by skin, GI tract, bone, or CNS

Question 11

Blastomyces dermatitidis Colony Morphology

Answer 11

25-30 C (mold phase) first yeast like, then fluffy, white colony

35-37 C (yeast phase) - yeast form grows as white to light brown, wrinkled colony
Yeast phase inhibited by cycloheximide

Question 12

Blastomyces dermatitidis Microscopic

Answer 12

25-30 C (mold phase) - septate hyphae bearing short terminal or lateral conidiophores that produce spherical, ovoid, or pyriform shaped conidia

35-37 C (yeast phase) - thick-walled, yeast-like cells budding on a broad base

Question 13

Paracoccidiomycosis brasiliensis

Answer 13

Chronic, occasionally fatal fungal disease
Beginning in the lungs and disseminating to the skin, mucous membranes, lymph nodes, and other internal organs

Question 14

Paracoccidioides brasiliensis Colony Morphology

Answer 14

25-30 C (mold phase) - various colony types (glabrous, brown colonies to wrinkled, floccose, beige, or white colonies)

35-37 C (yeast phase) - yeast form develops slowly, colony is folded, cream to tan, moist, soft, becoming waxy and yeast like

Question 15

Paracoccidioides brasiliensis Microscopic

Answer 15

25-30 C (mold phase) - Several weeks for conidia to develop, when present they appear laterally along the septate, branched hyphae. Intercalary and terminal chlamydoconidia may predominate

35-37 C (yeast phase) - large, round, thick-walled parent yeast cell with single and multiple budding attached by narrow connections
“Mariner’s wheel”

Question 16

Coccidiodiomycosis

Answer 16

Called San Joaquin Fever, Valley Fever
Caused by Coccidiodes immitis

Question 17

Coccidiodes immitis Location

Answer 17

Endemic to hot, dry regions of southwest United States
California, Arizona, Nevada, New Mexico, and Utah

Question 18

Coccidiodes immitis Clinical manifestations

Answer 18

Most virulent of the pathogenic fungi
1) Initial pulmonary infection
2) Pulmonary Complications
3) Extra pulmonary disease

Question 19

Coccidiodes immitis Initial infection

Answer 19

Characterized by symptoms resembling those of common cold or influenza
Immunocompromised patients may evolve into pulmonary nodules cavities, progressive pneumonia

Question 20

Coccidiodes immitis Colony Morphology

Answer 20

25 or 37 C - first moist, greyish and soon develops a white, cottony aerial mycelium. Becomes tan to brown with age
Reverse: White

Question 21

Coccidiodes immitis Microscopic

Answer 21

25-37 C (mold phase) - coarse, septate hyphae that produce thick-walled, barrel-shaped arthroconidia

Question 22

Coccidiodes immitis Tissue exams

Answer 22

Intact mature, spherules are thick-walled.
Spherules contain endospores which rupture and release the endospores