This document summarizes several systemic fungal infections. It describes histoplasmosis caused by Histoplasma capsulatum, which can infect the reticuloendothelial system and cause disseminated lesions. Blastomycosis by Blastomyces dermatitidis typically causes chronic lung infection but can disseminate, sometimes appearing as cutaneous lesions. Paracoccidiomycosis involves Paracoccidioides brasiliensis and can cause ulcerative granulomas. Coccidioidomycosis is caused by Coccidioides immitis and may manifest as primary pulmonary infection or disseminated disease. Cryptococcosis, often affecting immunocompromised individuals, is caused by

1. Systemic Mycoses
By Dr. Rakesh Prasad Sah
Assistant Professor, Microbiology

2. Introduction
• Systemic mycoses are fungal infections affecting internal
organs.
• Fungi enter the body via lungs, through the gut, para-nasal
sinuses or skin
• Then spread via bloodstream to multiple organs including the
skin

3. • Can cause a tremendous variety of health problems
including digestive difficulties, skin problems , asthma,
breathing difficulties etc.
• Often causing multiple organs to fail and eventually
resulting in the death of the patient

4. Classification of systemic mycosis

5. Histoplasmosis
• Causative agent  Histoplasma capsulatum
• Ds of R.E. system
• Is an intracellular parasite
• ds worldwide in distribution but is most common in America
• Source of Infection 
– spores +nt in soil enriched with excreta of birds or bats
– Inhalation of spores

6. Clinical features-
• Infection is asymptomatic.
• Some individual develop pulmonary disease which resembles
tuberculosis.
• Disseminated histoplasmosis develope in infected individuals.
• Involvement of reticuloendothelial system results in
lymphadenopathy, hepatosplenomegaly,fever, anaemia and
high fatality rate.
• Granulomatous and ulcerative lesion develop on skin and
mucosa.

7. Lab diagnosis-
• Sputum
• Bone marrow aspirate
• Peripheral blood
• Scrapping from dermal or mucosal ulcer
• Biopsis of lymph nodes.
1) Direct examination-smear stained with Giemsa stain or wright
stains, it shows small oval yeast cells.
2) Culture- SDA or brain heart infusion with cycloheximide &
chloramphenical.The yeast phase is formed at 37˚c .white cottony
mycelial growth contain large, thick walled, spherical spores with
tubercles or finger like projections at 250
C.

8. H.capsulatum-mycelial form.

9. Serological tests-
• Latex agglutination,precipitation and complement fixation test
is positive two weeks after infection.
• Increase in titre of antibodies shows progessive disease
•
• Histoplasmin test-delayed hypersensitivity test.it is similar to
tuberculin test bt antigen histoplasmin is used.Histoplasmin is
filterate antigen of H.capsulatum.
 Treatment- Amphoterin B.
 AFRICAN HISTOPLASMOSIS-causative agent-
H.duboisii..involve skin & subcutaneous tissues.

10. H.capsulatum-yeast cells in
macrophages.

11. Blastomycosis
• Causative agent- Blastomyces dermatitidis (dimorphic fungi)
• Chronic infection of the lungs but may spread to other tissues,
particularly skin, bone & genitourinary tract.
• Sources of infection -inhalation of conidia of fungus.
• Clinical features-
• Asymptomatic
• Mild primary pulmonary disease.
• Disseminated disease.
• Disseminated lesions found in AIDS.
• Cutaneous blastomycosis observe on skin of face.
– Initial lesion is a papule  around this secondary nodules develop
and colaesce  large elevated ulcerative lesions

12. MORPHOLOGY
• Appear spherical or oval budding yeast cells with thick walls
at 370
C, at 250
C , culture is filamentous with septate and oval
conidia.
 Lab diagnosis-
• Sputum
• Pus
• Scraping from skin lesion.
• Direct microscopy-10% KOH mount-thick walled yeast cells
with a single broad based bud.
• H&E and PAS show yeast cells.

13. B.dermititidis-yeast forms.

15. Culture
• SDA & Blood agar.
• Mycelial phase-25˚C
• Yeast phase-37˚C
• Culture incubate for 6 weeks.
Treatment-Amphoterin B.

16. Paracoccidiomycosis.
• Causative agent- Paracoccidioides brasiliences.
• Chronic granulomatous- lungs, mucosa,skin & lymphatic drainage.
• Source of infection-Inhalation of spores.
• Clinical features-
• Primary pulmonary infections spread by mucous membrane of
nose,mouth,lymph nodes,produce chronic granulomatous reaction.
• Ulcerative granulomas of buccal and nasal mucosa.

17. Morphology
• Yeast phase-37˚C with multiple buds in tissue.
• Mycelial phase-25˚C.
 Lab diagnosis-
• Specimens-pus,sputum,biopsis from granulomatous lesions.
 Direct microscopy-
• Examination in KOH mount show yeast cells with multiple
bud.
• Tissue stain with H&E and PAS stains.
• Culture-
• Mycelial phase-on SDA at 25˚C
• Yeast phase – on BHI at 37˚c.
• Treatment- Amphotericin B.

18. P.Brasiliensis : yeast form.

20. Coccidioidomycosis.
• Causative fungus- Coccidioides immitis.
• Primary infections of the lungs.
• Source of infections -inhalation of
arthrospores.
• Clinical features-
• Asymptomatic
• Primary pulmonary diseases-influenza like
fever(valley fever),severe pneumonia.
• Disseminated disease-CNS,skin,& bones.

21. • Mophology-
• It is spherule with thick doubly refratile wall with
endospores.
• Mycelial phase contains pseudohyphae which is
highly infectious.
• Laboratory diagnosis-
• Specimens-sputum,pus,biopsy material.
• Direct microscopy –detect mature spherules
• Culture-
• Use SDA medium.
• Petri dish not used.
• Incubate 25˚c for 3 weeks.
Skin test -coccidiodin antigen is used.
• Positive test-between 3-21 days of symptoms.

22. Coccidioides immitis

24. CRYPTOCOCCOSIS.
• Causative agent - Cryptococcus neoformans.
• Abundant in faeces of pigeons.
• MORPHOLOGY –
• Spherical budding cell, have capsule.
• True yeast.
• Capsule can be demonstrated by india ink preparation.
• SOURCE OF INFECTION –
• Inhalation of dust containing yeast cells.

26. Pathogenesis -
• Pathogenic in humans & animals.
• Occurs in immuno compromised host.
• Asymptomatic.
• Pulmonary cryptococcosis – leads to pneumonitis
• Cryptococcal meningitis occurs by haematogenous
spread, mostly seen in AIDS patients.

27. • Skin,lymph-nodes,bones & other organs alse gets to
affected.
• Cutaneous cryptococcus varies from small ulcers to
large granulomas.
• Visceral forms of cryptococcal infection stimulate
tuberculosis and cancer clinically

28. Lab diagnosis
• Specimen - CSF, sputum ,pus, brain tissue.
• Direct microscopy-
1) Specimen mixed with drop of india ink-round budding yeast
cells.
2) Gram staining –gram positive yeast cells.

29. • Culture
• On SDA, it shows
smooth, mucoid, cream
colored colonies.
• NIGER SEED AGAR is
differential medium for
presumptive
identification.  Brown
colonies at 300
C within 1
week.
Phenoloxidase
Caffeic acid
Melanin

30. • Latex agglutination test .
• Animal inoculation test – intracerebral or intraperitoneal
inoculation.
• Other tests – C. neoformans hydrolyses urea.

31. Differentiation of C.neoformans from other
non-pathogenic cryptococci –
C.neoformans has ability to –
– Grow at 37˚C.
– Hydrolyse urea
– Produce brown colonies on niger seed agar.
– Produce disease in mice.

32. C.neoformans – India ink
preparation.

33. C.neoformans.