1. The Major Mycoses and Causative Fungi
Type of Mycosis Causative Fungal Mycosis
Agents
Endemic Paracoccidioidomycosis
Paracoccidioides brasiliensis
(primary, systemic)
Coccidioides immitis, C Coccidioidomycosis
posadasii
Histoplasma capsulatum Histoplasmosis
Blastomyces dermatitidis Blastomycosis
Opportunistic Candida albicans and other Systemic candidiasis
Candida species
Cryptococcus neoformans Cryptococcosis
Aspergillus fumigatus and other Aspergillosis
Aspergillus species
Species of Rhizopus, Absidia, Mucormycosis (zygomycosis)
Mucor, and other zygomycetes
Penicillium marneffei Penicilliosis

2. Systemic vs. Opportunisic
Mycoses
MYCOSES SYSTEMIC OPPORTUNISTIC
FORMS Dimorphic Monomorphic
GEOGRAPHICAL Environment Normal flora
PORTAL OF ENTRY Lungs Variable
HOST Immunocompetent Immunocompromised
RECOVERY Good prognosis Poor prognosis

3. SYSTEMIC MYCOSES
 North American Blastomycosis
 South American Blastomycosis
 Darling’s Disease
 San Joaquin Valley Fever

4. Coccidioidomycosis
Etiology Coccidioides immitis, C posadasii
Ecology Soil
Geographic Semiarid regions of southwestern
distribution United States, Mexico, Central and
South America
Conidia (< 35 °C) Hyaline septate hyphae and
arthroconidia, 3 x 6 m
Tissue form Spherules 37⁰C, 10–80 m or larger,
containing endospores, 2–4 m

5. Branched hyphae w/ alternating
arthrospores and empty cells

6. Cultural Characteristics
• Sabaraud’s Agar incubated at 20-30C
• Colony: white, gray or brownish color with
powdery, wooly or cottony texture ( extreme
caution should be exercised)
• Spherules- produced on a complex medioum
under 40C 20% CO2

11. Coccidioides immitis
(SW USA, Latin America)
Diseases
Coccidiomycosis- mild lung infection
– asymptomatic or mild pneumonia
– Dissemination leads to bone granulomas or
meningitis.
• Erythema nodosum (red tender nodules on
extensor surfaces, indicated DTH rxn to fungal
antigens – NO organisms in lesions
• Arthragias- “valley fever”, “desert rheumatism”

12. Habitat/Trans
• Endemic in arid parts of SW USA, Latin America.
Pathogenesis
• Arthrospores are inhaled.
• Arthrospores make spherules w/ doubly
refractive wall filled with endospores.
• On rupture, endospores released to form
new spherules which spread by direct
extension or via blood.

13. Diagnosis
• Skin tests w/ coccidiodin or spherulin
Treatment
• Amphotericin B
• Itraconazole

14. Histoplasmosis
Etiology Histoplasma capsulatum, Darling’s Disease
Ecology Bat and avian habitats (guano); alkaline soil
Geographic Worldwide, but endemic to Ohio, Mississippi
distribution river valleys. (Think OHIstOplama) ; central Africa
(var duboisii)
Conidia (< 35 °C) non encapsulated, Hyaline septate hyphae
Two kinds of asexual Mold: Tuberculate macroconidia,
spores: macroconidia, 8–16 m, and small oval or
pyriform (pear shaped) microconidia, 3–5 m
Tissue form Oval yeasts, 2 x 4 m, intracellular in macrophages
sexual stage : **** EXOANTIGEN TEST
Emmonsiella H. capsulatum : H and M bands
capsulata

15. • Giemsa and gram staining do not “take” on
the cellwalls of H. capsulatum
• cells often appear to be surrounded by an
empty areola
• which was incorrectly taken to be a capsule
• + H.capsulatum

16. Histoplasma capsulatum
(Ohio and Mississippi river valleys)

20. *NOTE: Sepedonium- a fungi characterized by
tuberculate macroconidia
Difference:
no microconidia and it is a monomorphic fungi
**NOTE: Leishmania species
Difference: Leishmania do not stain w/ fungal
stain and it has a central nuclear body

21. Pathogenesis
• Inhaled microconidia develop into yeasts
within macrophages.
• (Histoplasma Hides in macrophages) Spreads
quickly, calcified granulomas.

22. Diagnosis
• Suitable material for diagnostic analysis:
Bronchial secretion
Urine
scrapings from infection foci
• For microscopic examination:
Giemsa or Wright staining is applied and yeast cells are
looked for inside the macrophages and
polymorphonuclear leukocytes.
 Cultures on blood
Sabouraud agar must be incubated for several weeks.
Antibodies are detected using the complement fixation
test and agar gel precipitation.
The diagnostic value of positive or negative findings in a
histoplasmin scratch test is doubtful.

23. Diagnosis
• ID budding yeasts WITHIN macrophages.
• DTH skin test w/ histoplasmin
Treatment
• Amphotericin B
• Itraconazole

25. Blastomycosis
Etiology Blastomyces dermatidis
Ecology Unknown (riverbanks?)
Geographic distribution Endemic along Mississippi, Ohio, and St.
Lawrence River Valleys and in Southeastern
United States
Conidia (< 35 °C) YEAST FORM : Round yeast w/ doubly
refractive wall, single broad based bud
MOLD FORM : Branched hyphae w/ small
conidia bearing single globose to piriform
conidia, 2–10 m
Tissue form Thick-walled yeasts with broad-based, usually
single buds, 8–15 m

26. North American Blastomycosis/
Gilchrist’s disease
• RT: Mold: lollipop conidia
• 37C: Yeast: yeast cell w/ broad based single budding
· ****EXOANTIGEN TEST
Test for:
• systemic fungi (immunodiffusion)
• B. dermatitidis : appearance of spc. A band
Treatment
• Amphotericin B
• Itraconazole

27. Blastomyces dermatitidis
A: In tissue or culture at 37 °C.

28. B: In culture at 30 °C on Sabouraud's agar

30. Budding yeast cells of Blastomyces Mould form of Blastomyces dermatitidis in
dermatitidis in culture. When cultures are culture. The lollipop appearance of the
incubated at 37°C, large, broad-based conidium on a conidiophore is characteristic
budding yeast with a double-contoured all
of the environmental mould form for this
are detected which are characteristic for
dimorphic fungus. (Lactophenol cotton blue
the yeast phase of this dimorphic fungus.
(Lactophenol cotton blue stain; ×400) stain; ×400)

32. Paracoccidioidomycosis
Etiology Paracoccidioides brasiliensis
Ecology Soil fungus
Geographic distribution Central and South America
Latin America
Conidia (< 35 °C) Hyaline, branched septate hyphae and rare
globose conidia and chlamydospores
Round yeast w/ thick wall and
YEAST FORM multiple buds
Hyaline, septate hyphae and rare globose
Tissue form conidia and chlamydospores

33. South American Blastomycosis
Paracoccidioides brasillensis
• Dimorphic fungi
• RT: Mold: Chlamydoconidia
• 37C: Yeast: yeast cell w/ multiple buds
PILOT WHEEL/ MARINER’s SHIP WHEEL
• ****EXOANTIGEN TEST:
• P. brasilliensis : bands 1, 2, 3
Treatment
• Amphotericin B
• Itraconazole

35. OPPORTUNISTIC MYCOSES
Infections due to fungi of low virulence in
patients who are immunologically
compromised
All Monomorphic

36. Candida
YEAST FORM : Oval yeast w/ single bud and
“psuedohyphae”
C. albicans germ tubes w/ chamydospores at
37’C
MOLD FORM : NONE

43. Characteristics:
Oval yeast w/ single
bud. Can appear as “pseudohyphae” w/in tissue
Habitat/Trans:
 Normal flora of
upper respiratory, GI, female GU, so NO person-
person transmission.
NEVER in the blood

44. Infections with Candida usually occur
when there is some alteration in:
• Cellular immunity
• Normal Flora
• Physiology

45. Oral Thrush

46. Diseases
Vulvovaginitis- vaginal itching/discharge, favored by
high pH, diabetes, antibiotics, oral contraceptives,
menses, pregnancy
Cutaneous candidiasis- skin invasion favored by
warmth, moisture: inframammary folds, groin
• Oral thrush- white exudate in immunocompromised
• Esophogeal candidiasis- AIDS defining illness w/
substernal chest pain, dysphagia
• Disseminated candidiasis- Immunocompromised
and IVDA

47. Diagnosis
C.albicans
differentiated from other Candida by germ
tubes in serum at 37’C and chlamydospores.
Skin tests are positive in normal adults, indicator
of good cellular immunity.

48. Treatment
• Skin infections w/ topical clotrimazole
• vaginitis w/ imidazole suppositories
• oral thrush w/ “swish ‘n swallow” nystatin
• systemic candidiasis w/ amphotericin B

49. Cryptococcus
YEAST FORM: Oval budding yeast w/
polysccharide capsule
MOLD FORM: NONE

50. Habitat/Trans
Soil w/ pigeon crap
(Think: cryptoCOCCUS= pigeon CACA)
Pathogenesis:
• Humans inhale Yeast

51. Cryptococcus neoformans
Diseases
• Usually asymptomatic, can cause pneumonia,
bone/skin granulomas.
Dissemination causes
• cryptococcal meningitis, subacute.

52. Characteristics
Oval budding yeast w/ wide polysaccardide
capsule (India ink stain)
• Virulence factors
1. Anti-phagocytic polysaccharide capsule
2. Antioxidant melanin
3. Ability to grow at 37°C

53. Cryptococcus neoformans in India ink
preparation of spinal fluid. The large capsule is
visible

55. Colonies of Cryptococcus neoformans usually appear
mucoid when first isolated. Some strains are poorly
encapsulated and lack the mucoid appearance.
(Sabouraud dextrose agar)

56. Clinical Findings
Chronic meningitis
 Cerebrospinal fluid pressure- elevated
 protein -elevated
 cell count -elevated
 glucose -normal or low
Patients may complain
 headache
 neck stiffness
 Disorientation
 lesions in skin, lungs, or other organs
• The course of cryptococcal meningitis may fluctuate over long
periods, but all untreated cases are ultimately fatal.

57. Diagnostic Laboratory Tests
Specimens
spinal fluid
tissue
Exudates
Sputum
 blood
urine
Spinal fluid is centrifuged before microscopic
examination and culture.
• Microscopic Examination
– wet mounts, both directly and after mixing with India ink, which
delineates the capsule.

58. Diagnostic Laboratory Tests
Culture
 Cycloheximide inhibits C. neoformanns
 growth at 37 °C + urease.
 colonies : brown pigment
Serology
 Tests for capsular antigen can be performed on cerebrospinal fluid and
serum
 latex slide agglutination test - + cryptococcal antigen
 Indirect fluorescent antibody
Treatment
 Combination therapy of amphotericin B
 Fluconazole offers excellent penetration of the central nervous system
 Highly Active Antiretroviral Therapy (HAART) better prognosis for
HIV/AIDS

60. Aspergillus
YEAST FORM: NONE
MOLD FORM: V-shaped septate hyphae w/
radiating chains of conidia

62. Aspergillus fumigatus
Invasive necrotizing pneumonia in AIDS, Molds
grow in pulmonary cavities and produce
Aspergilloma (FUNGUS BALL), requiring surgery.
Allergic bronchopulmonary
aspergillosis, type I hypersensitivity reaction like
asthma.
A.flavus- grows on cereal or nuts produces
aflatoxins (toxic, carcinogenic to liver)

70. Characteristics
• Septate hyphae, V-shaped branches
• Conidia form radiating chains. (compare w/
mucor/rhizopus)

71. Habitat/Trans
• Saprophytic molds
• EVERYWHERE!
Pathogenesis:
• Transmission by airborne conidia colonize and
invade abraded skin, wounds, burns, ear,
cornea

72. Diagnostic Laboratory Tests
Specimens
 Sputum
 other respiratory tract specimens
 lung biopsy tissue
Microscopic Examination
 KOH or calcofluor white
 histologic sections
• +hyaline, septate, and uniform in width (about 4 m) and
branch dichotomously
Culture
room temperature - + CONIDIA

73. Diagnostic Laboratory Tests
Serology
• precipitins positive aspergilloma or allergic forms of aspergillosis
• circulating cell wall galactomannan is diagnostic.
Treatment
Aspergilloma
-itraconazole
- amphotericin B and surgery
Less severe chronic necrotizing pulmonary disease
-voriconazole
- itraconazole
Allergic forms of aspergillosis
-corticosteroids
-disodium chromoglycate

75. Mucor/Rhizopus
YEAST FORM: NONE
MOLD FORM: Right-
angle branched
nonseptate Gray to brown to black colony filling a Petri
dish in 2 to 3 days.
hyphae w/ sporangium

79. Characteristics
• Nonseptate hyphae w/ broad irregular walls
and right angle branches (compare w/
aspergillus)
• Endospores inside of sporangium

80. Diseases
• Rhinocerebral mucormycosis- associated w/
diabetes, caused by infection of nasal mucosa
with invasion of sinuses/orbit. Molds
proliferate in walls of blood vessels.
• (Think MUCOR/Rhizopus invades MUCOSA)
• Important in immunocompromized patients
paricularly leukemic patients

81. Habitat/Trans
• Saprophytic molds
• EVERYWHERE!
Diagnosis:
Biopsy
Treatment:
Amphotericin B,
Surgical resection

85. Penicillium marneffei
• A dimorphic fungus grow as mold at 25 °C
and as arthroconidia at 37 °C
• causes tuberculosis-like disease in AIDS
patients
• Drug of choice is amphotericin B
• Produces a red pigment