4. Histoplasma
• H. capsulatum is a dimorphic fungi
• H. capsulatum causes histoplasmosis
– reticuloendothelial cytomycosis
– caver’s disease
– spelunker’s disease
–Darling’s disease
5. Histoplasma capsulatum
• Morphology
Macroscopic
Slow growth
White to dark tan
Woolly, cottony or granular
Microscopic
Microconidia small, one-celled,
round, smooth-walled
(2-5µm)
Tuberculated macroconidia w/
typical thick walls , fingerlike
projections (7-12µm)
6. Histoplasma capsulatum
• Infects RES – bone marrow specimen of
choice
• Primary focus pulmonary
• may be confused with Sepedonium
7. Histoplasma capsulatum
• Identification Techniques
1.
Wrights and Giemsa stain
yeast cells are commonly seen w/in monocyte
and macrophages
2. Sabourauds dextrose Agar
shows typical structure e.g. tuberculate
macroconidia
8. Histoplasma capsulatum
• MOT
endemic in Ohio, Missouri and Mississippi
river valleys
grows in soil, particularly if the soil is heavily
contaminated w/ bird droppings
Histoplamosis is acquired by the inhalation
of microconidia of H. capsulatum
9. Histoplasma capsulatum
• Prevention and Control
Asymptomatic or mild primary infection –
no therapy needed
With progressive lung lesion – oral
ketoconazole
In disseminated diseases – amphotericin B
There are no means of prevention except
avoiding exposure in endemic area
10. Histoplasma capsulatum
• Pathology
• Chronic pulmonary histoplasmosis in patients
w/ chronic obstructive pulmonary disease
may occur
» Other manifestations of the disease are
mediastinitis, pericarditis, and mucocutaneous
lesions.
12. Coccidiodes imitis
•
•
•
•
•
•
habitat-soil of many arid regions
infectious form- arthroconidia
MOT-inhalation
virulence- extracellular proteinase
Difficult to convert from mold to yeast phase
Endemic in desert southwest and semi rid
regions
19. Paracoccidioides brasiliensis
• Central and South America (Brazil,
Venezuela, Colombia)
• High humidity and temperature
MORPHOLOGY
• YEAST
• The yeast forms consists of Oval or
globose cells 2- 30 microns, in diameter,
with small buds attached by a narrow
neck encircling the parent cells.
• “Mariners Wheel”
•
MOLD
• Similar to Lollipop
forms
20. Pathology
• P. brasiliensis is the causative agent of
•
– Paracoccidiomycosis (South American
blastomycosis, Brazilian
blastomycosis, Lutz-SplendoreAlmeids disease and paracoccidiodal
granuloma)
– Is pulmonary and infection is usually
asymptomatic, subsequent
dessimenation leads to the formation
of ulcerative granulomatous lesions of
the buccal, nasal and occasionally
gastrointestinal mucosa.
Disease presentation:
–
–
–
Pneumonia
Disseminated infection
Extrapulmonary lesions on the face and oral
mucosa
• Lymphatic system spleen, Intestines,
Liver involvement
21. Mode of Transmission
• Transmitted by
inhalation of
the spores
• Restricted to South
and Central America
• Isolated in acidic soil
and its growth
requires increased
humidity
22. Identification techniques
• Endemic in Central and South
America (Brazil, Venezuela,
Colombia)
– In soil (High humidity and
temperature ~23°C.)
• Serological findings (detection of
specific antibodies)
• Microscopy – Sputum , Pus,
• Biopsy of glaucomatous lesions
• Direct histopathologic examination
of infected tissue
• Yeast
Multiple buds resembling “mariners
wheel”
These daughter cells are connected by
a narrow base, giving the appearance
of a “Mickey Mouse Cap”
23. Identification techniques
• Culture
– kept for 6 weeks
– 25 c moulds
– 37 c yeasts
– Saboraud’s agar
– At room temperature it grows a
non spore forming septate fungus
– Brain Heart Infusion at 35° C
– It produces yeast that is seen in
tissue
• Direct Microscopy
– 10-20% KOH
– 1-2 drops are used
– demonstration of multiple
budding yeast
• Others
– Paracoccidioidin skin test
– Complement fixation test
– Immunodiffusion test
24. Treatment and Prevention
• Amphotericin B
• Itraconazole
• Long term therapy is
required
• Prevent inhalation of
dust in endemic area
26. Morphology
• Yeast form:
– Large yeast cells
(8-12 µm)
– Blastoconidia
attached by broad
base
– Double contoured
wall
• Mold phase:
– Lollipop forms
27. Macroscopic Morphology
• Slow to moderate growth
– White to dark tan
• Young colonies
– Tenacious
• Older colonies
– Glabrous to wooly
• Oval ,pyriform, to globuse
smooth conidia borne on
short, lateral hyphalike
conidiophores
28. Mode of Transmission & Epidemiology
• Presumably owing to men’s greater
occupational and recreational exposure to the
soil
• It grows in moist soil rich in organic material,
forming hyphae with small pear-shaped
conidia
• Inhalation of the conidia *
29. Epidemiology
• North America and parts of Africa*
• Mississippi and Ohio River basins
– St. Lawrence River basin*
30. Identification Technique
• KOH (10%) or Calcofluor white –use to aid for
examination of yeast cell
• 22 C – colonies may be white tan or brown and
may be fluffy or glabrous
• Spicules- seen in the center of colonies
• 37 C (blood Agar) – broad base budding yeast cell
31. Prevention & Control
• Ketoconazole
• Surgical excision
• There are no means of prevention
32. Pathology
• Primary infection: Flulike symptoms
• Asymptomatic and cannot accuratety define
the time of onset
• Pulmonary disease (cough,weightloss, chest
pain and fever)
• Progressive pulmonary or invasive disease
may follow.(ulcerative lesions of bone and
skin)
33. • ** immunodeficient
patient : multiple organ
system
• Blastomycosis
- Gilchrist disease, North
American Blastomycosis
and chicago disease
- Occurs primarily: North
America and Parts of
Africa
34. • United States(endemic)- Mississipi , Ohio river
basins and St. Lawrence River basin
** Dogs and Horses
35.
36. Sporotrichosis
• Sporothrix schenckii
– Cutaneous inoculation of fungus from penetrating
injury with a spore or thorn (rose bush)
– Initial skin lesion w/wo ulceration
– Lymph-cutaneous spread – bone – systemic
– Pulmonary and CNS infections are rare but
reported
37. Starts as one ulcerative lesion and then chains
Up the lymphatics – can involve lymph nodes
and bone
38. Sporothrix schenckii
• Dimorphic fungus
• MOLD PHASE
– 30*˚C growth in 3 -5 days
– Turns brown to black over time
– Septate hyphae with conidia in daisy wheel
pattern
• YEAST PHASE
– At 37˚C small oval yeast cells,
elongated 2 – 5 µM, described as cigar bodies
39. Sporothrix schenckii
• Histology –
– Pyogenic – to – granulomatous inflammation
– Hard to find yeast in human tissue
– Asteroid body known as Splendore-Hoeppli
phenomenon can be seen – also seen in:
•
•
•
•
Zygomycetes (mucorales)
Aspergillus
Blastomycosis
Candida
