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1. Fungi Causing Systemic Mycoses
= majority causes inapparent infection
= causative organism are dimorphic fungi
1. Blastomyces dermatitides
Characteristics:
= dimorphic can exist as:
mold in soil, yeast in tissue
Yeast form is round-shaped with a thick
refractile wall and single broad-based bud
= natural habitat Is soil rich in organic material

2. Disease: Blastomycosis (Gilchrist’s Dse, North
American)
Blastomycosis
= a chronic infection characterized by formation of
suppurative and granulomatous lesion found
mainly in the lungs and disseminate
throughout the body
MOT = inhalation of airborne spore (conidia)
Pathogenesis: = infection occurs mainly in the
respiratory tract
= inhaled conidia differentiate into yeast
cell which initially cause abscesses
followed by formation of granuloma
= dissemination rare, but when it occurs
skin and bone are the most commonly
involved.

3. Laboratory Diagnosis:
1. Direct microscopic examination of sputum or skin
scrapping (KOH mount)/Tissue biopsy:
= demonstrate charac. thick walled “yeast cell with
single broad-based bud”
2. Culture - SDA
= grows as fluffy, brownish to white fungus which
produces pyriform spores
3. Hypersensitivity test – Blastomycin test
= Serological test not useful
Treatment: Itraconazole (drug of choice)
Amphotericin B - used to treat severe cases
Surgical excision helpful
Prevention: No vaccine or prophylactic drug available

4. 2. Coccidiodes immitis
Characteristics:
= dimorphic fungus that exist as:
spherules in tissues containing endospores
mold at 250
C in soil which forms hyphae with
alternating arthrospores
= natural habitat is soil
Disease: Coccidiodomycosis (San Joaquin Valley Fever,)
Dessert Fever
= disease simulate pneumonia wherein large part of the
lung becomes consolidated
MOT: inhalation of airborne arthrospores
Pathogenesis: Arthrospores inhaled →to the lungs →
forms spherules filled with endospore → rupture →
endospore release → forms new spherules → disseminate
throughout the body

5. Septate hyphae
Arthroconidia
Septate hyphae

6. Laboratory Diagnosis:
A) Microscopic examination of tissue scrapping or sputum
(KOH mount) = demonstrate the characteristic
spherules containing endospores
B) Culture
Sabouraud medium – presence of hyphae containing
arthrospores.
C) Serological test
Precipitin test– demonstrate a rising titer of IgM Ab
(indicates recent infection)
CF test - a rising titer IgG antibody indicates
dissemination of infection
D) Skin test – Coccidioidin test – using mycelial extract or
spherulin (an extract from spherules) as
antigen
= (+) test indicate prior infection but not necessarily
active disease
= useful in determining whether patient has been

7. Treatment: Ketoconazole (for primary infection)
Amphotericin B/Itraconazole (for disseminated infection)
Fluconazole - drug of choice in cases of meningitis
Prevention: No vaccine and Prophylactic drug available

8. 3. Paracoccidiodes braziliensis
Characteristics:
= dimorphic fungus exist as: mold in soil
yeast in tissue
(yeast form is thick walled with multiple buds)
resembling a ship steering-wheel
= habitat - soil
Disease: Paracoccidioidomycosis
(South American Blastomycosis)
= chronic granulomatous disease of the skin,mucous
membrane, lymph node and internal organs.
MOT : inhalation of airborne conidia
Pathogenesis: = spores are inhaled an early lesion
occurs
ion the lungs which disseminate to other organ
= asymptomatic infection common

9. Laboratory Diagnosis:
A) Direct microscopic examination from pus or
tissues (KOH mount)
= presence of large yeast cell w/multiple
buds
B) Culture
Sabourauds agar – presence of septate hyphae
with microconidia
C) Skin test not useful
D) Serological: CF/Immunodiffusion test - rise in AB
titer significant
Treatment: Itraconazole
Prevention: No vaccine available, Prophylactic drug
available

10. 4) Histoplasma capsulatum
= dimorphic fungus that exist as:
yeast cell in tissue w/c forms 2types of asexual spore
a) Tuberculate macroconidia
(thick-walled finger like projection)
b) Microconidia- thin, small, smooth-walled
mold in soil enriched with bird droppings
Disease: Histoplasmosis (Darling’s Disease)
= acute, benign pulmonary disease acquired by
inhalation of airborne spores (microconidia)
which are present from dropping of birds
= inhaled spore are engulfed by macrophages which
developed in to yeast form
= in tissue the organism occurs as oval body yeast
cell inside macrophages which spread
throughout the body especially liver and spleen

12. Laboratory Diagnosis:
A. Microscopic examination of sputum, tissue biopsy, bone
marrow aspirate
= oval yeast cell within macrophages
B. Culture
Sabourauds agar = presence of septate hyphae with
tuberculate chlamydospore in culture at 250
C is
diagnostic
BHIA – presence of fusiform blastospores with large
vacuole giving a characteristic cresent-shaped
appearance
C. Skin test – Histoplasmin test
-using mycelial extract as antigen
-useful for epidemiologic determination of incidence
of infection
-not use to diagnose actual disease
Treatment: Amphotericin B – for disseminated infection
Itraconazole - for pulmonary infection
Prevention: None (no vaccine available)

13. Budding yeast cell
inside macrophages

14. Fungi Causing Opportunistic Mycoses
= produce disease in those individual with impaired host
defenses
1. Candida albicans
Characteristics:
= is an oval yeast cell with a single bud
= part of the normal flora of the mucous membrane
of the upper respiratory tract, gastrointestinal
and female genital tract
= in tissues can appear as yeast cell or as
psuedohyphae (which are elongated yeast that
visually resembles hyphae but are not true hyphae)
= CHO fermentation reaction differentiate C-albicans
from other specie of Candida

15. MOT: - part of the normal of the skin, mucous membrane
and gastrointestinal tract of human
= no person to person transmission
Pathogenesis: Opportunistic pathogen
= disease may results when host defenses are
impaired
Diseases:
1. Thrush (Moniliasis)
2. Vulvovaginitis
3. Infection of the Nail (Paronychia)
4. Skin lesion occurs frequently in moisture-damage
skin
5. Systemic Candidiasis (disseminated form)

16. Laboratory Diagnosis:
A. Direct microscopic examination (KOH mount)
= presence of budding yeast cell w/pseudohyphae
B. Culture
SDA – presence of yeast cell, pseudohyphae
and large chlamydospore
Germ tube form in serum at 370
C differentiate
albicans from other species
C. Skin test with candida antigen
= (+) among immunocompetent adult and
are used as indicator that a person can mount
a cellular immune response

17. Treatment: Nystatin / Miconazole oral/topical
for skin and mucous membrane disease
Amphotericin B - disseminated infection
Ketoconazole – for chronic mucocutaneous
candidiasis
Prevention: No vaccine available
= predisposing factors should be reduced or
eliminated
= Clotrimazole trochis / Nystatin–used for
prevention of oral thrush

19. 2. Aspergillus fumigatus/Aspergillus flavus/Aspergillus
niger
Characteristics:
= exist only as mold with septate hyphae that branch
at a V-shaped angle
= monomorphic
= organism is normally found in soil
Diseases: 1. Aspergillosis (major disease)
= a granulomatous necrotizing disease of the lung
which often disseminates hematogenously to
various organs of the body
= involving the skin, eyes, ear, and other vital organ
= acquired by inhalation by airborne conidia
= can colonize and invade abraded skin and paranasal
sinuses causing fungal sinusitis
2. Allergic bronchopulmonary aspergillosis

21. Pathogenesis:
= opportunistic pathogen
= produce invasive disease among immunocompromised
individual
= organism can invade bloodvessels causing thrombosis
and infarction
= patient with lung cavity (tuberculosis) may develop
fungal ball (Aspergilloma)
= allergic patient with bronchial asthma can develop
allergic bronhopulmonary aspergillosis
Laboratory Diagnosis:
A. Microscopic examination (KOH mount) = presence of
hyaline septate hyphae, dichotomously branched
B. Culture – SDA – shows colonies with characteristic
radiating chain of conidia
C. Serological – detect IgG precipitin in patient with
aspergilloma and IgE antibody in patient with
bronchopulmonary aspergillosis

22. Treatment: Amphotericin B – for invasive aspergillosis
Surgical removal – for aspergilloma (fungus ball)
Steroid – recommended for allergic
bronchopulmonary aspergillosis
Prevention: No vaccine / Prophylactic drug available

23. 3. Rhizopus/Mucor
Characteristic:
= mold with non-septate hyphae w/ sporangiospore
that typically branch at 90O
angle
= monomorphic
= habitat in soil
MOT: inhalation of airborne spores
Disease: Mucormycoses (Zygomycoses;
Phycomycoses)
= is a systemic disease cause by saprophytic mold
(Mucor, Rhizopus and Absidia) found widely
in the environment
= acquired by inhalation of airborne asexual spore

24. Laboratory Diagnosis:
1. Microscopic examination of tissue (KOH mount)
= presence of non-septate hyphae that branch at
wide right angle
2. Culture – SDA - large hyaline coenocytic hyphae with
spores found inside sporangium
3. Serologic test – not available
Treatment: Amphotericin B
Prevention: No vaccine / Prophylaxis drug available

25. 4. Cryptococcus neoformans
= is an oval yeast-like budding cell surrounded by a
wide polysaccharide capsule
= not dimorphic
= habitat soil enriched with pigeon droppings
Disease: Cryptococcosis(Torulosis, European
Blastomycosis)
= most common life-threatening fungal disease in
AIDS patient
MOT: inhalation of airborne yeast cell
= no human to human transmission
Pathogenesis:
= lung infection as a result of inhalation is often
asymptomatic or may produce pneumonia
= disease occurs in patient with altered cell
mediated immunity especially AIDS patient
= spread via blood stream to the CNS and result to

26. Laboratory Diagnosis:
= Direct visualization of the encapsulated yeast-like
budding cell from spinal fluid by India Ink staining
(yeast cell surrounded by a wide unstained capsule)
= Culture (spinal fluid/sputum) SDA – presence of
encapsulated yeast cell.
= Serological – Latex particle agglutination test
- detects polysaccharide capsular antigen in
spinal fluid
Treatment: Amphotericin B plus Flucytosine for
meningitis
Prevention: No vaccine
= Cryptococcal meningitis can be prevented in AIDS
patient by oral Fluconazole

27. Capsule
Budding
yeast