Histoplasma capsulatum

1
Histoplasma capsulatum
Inside Tissue Phagocytes
2
Histoplasma capsulatum
Methenamine Silver Stained Lung Tissue
3
(No Transcript)
4
H. capsulatum fluorescent Ab stain lung tissue
5
Histoplasmosis

• Laboratory confirmation
• H.capsulatum is a slow-growing mould on primary
  isolation media not containing blood or other
  enrichments incubated at 30oC
• Colonies are white to brownish pigment mainly
  seen on bottom of colony
• Produces macroconidia that are one-celled, round
  (7-12? m) with knobby projections (tuberculate)

6
Histoplasma capsulatum
Reverse
Front
Sabourauds Dextrose Agar Room Temperature
7
Histoplasmosis

• Laboratory confirmation
• Microconidia are often produced that are one-cell
  round and smooth (2-5? m )
• Sepedonium species are saprobic fungi that
  closely resemble H. capsulatum microscopically
• However, Sepedonium grows much more rapidly than
  H. capsulatum, is not dimorphic, and gives a
  negative exoantigen test (no soluble Ag).

8
Histoplasma capsulatum
Tuberculate Microconidium
Microconidia
Slide culture Potato Dextrose Agar Room
Temperature
9
Sepedonium Species
Slide Culture Potato Dextrose Agar Room
Temperature
10
Blastomycosis

• Etiology Blastomyces dermatitidis
• Epidemiology
• World wide distribution, but predominates in
  North America N.A. blastomycosis
• USA Mississippi, Ohio, and Missouri River
  Valleys, Great Lakes area, and the mid-Atlantic
  coastal regions
• Largely overlaps H. capsulatum endemic areas