Systemic Mycoses Flashcards
Systemic Mycoses
Transmitted by inhalation of____ from_____ environments; fungi isolated from____ soil or in soil mixed with_____
conidia
humid
acidic
guano
SYSTEMIC MYCOSES
• Fungal infections that invade the____
• Predominantly affect_____ hosts
•_____ mycoses can cause disease in healthy individuals.
• Profound impact on human health
deep organs (endemic and opportunistic fungal pathogens)
immunocompromised hosts
Endemic
SYSTEMIC MYCOSES
• Increasing in morbidity and mortality due to increase in (4)
• Fungal pathogens have acquired the ability to overcome the____
• susceptible hosts
• international travel
• migration
• human encroachment on the environment
lung innate immune responses
Blastomycosis
Blastomyces dermatitidis ( species
complex)
Coccidioidomycosis
Coccidioides immitis/ C. posadasii
Histoplasmosis
Histoplasma capsulatum
Paracoccidioidomycosis
Paracoccidioides brasiliensis
Talaromycosis
Talaromyces (Penicillium) marneffei
Emergomycosis
Emergomyces (Emmonsia) spp.
USA (Midwest, SE, east, SC), Canada (Ontario, Quebec, Manitoba, Saskatchewan), Africa (east, south), India
Blastomycosis
Central Valley of California, eastern Washington state, Arizona, Texas, Utah, Mexico, Central & South America
Coccidiodomycosis
USA (Ohio, Mississippi River Valleys), Central & South America
Histoplasmosis
South America (Brazil, Venezuela, Columbia, Argentina, Paraguay, Ecuador)
Paracoccidiodomycosis
China (Guangxi province), Thailand, Hong Kong, India, Taiwan, Laos, Cambodia, Malaysia, Myanmar,
Indonesia, Vietnam
Talaromycosis
Asia, Europe, Africa, North America
Emergomycosis
_______is a systemic fungal infection caused by_______ spp, primarily______.
It is a thermally dimorphic fungus, existing as a mold in the environment and converting to yeast in human tissues upon inhalation.
The disease predominantly affects the lungs but can disseminate to the (3)
Blastomycosis
Blastomyces species
Blastomyces dermatitidis
skin
bones
CNS
Lung infections (79%, 25%-40% disseminated mycosis any organ), preferentially skin, bones, & CNS
Blastomycosis
• a.k.a.
North American …
Gilchrist disease
Chicago disease
Blastomycosis
BLASTOMYCOSIS
• T.C._____ discovery: budding yeast form in tissues and hyphal organisms in culture from a patient with skin disease in 1894.
• took ______to understand that cutaneous manifestation was associated with pulmonary involvement…
all cases of skin involvement resulted from dissemination from the lungs
Gilchrist’s
50 years
Blastomyces species belong to the phylum_____ and the family_____.
Ascomycota
Ajellomycetaceae
BLASTOMYCOSIS
•________– primary causative species.
•_______ (2013) – associated with outbreaks; part of the B. dermatitidis species complex.
Blastomyces dermatitidis
Blastomyces gilchristii
BLASTOMYCOSIS
•________– infects immunodeficient humans and domestic animals.
•________– found in Africa and the Middle East.
•________ – linked to extrapulmonary infections.
Blastomyces helicus (2017)
Blastomyces percursus (2017)
Blastomyces emzantsi (2020)
MOT of BLASTOMYCOSIS
• Inhalation of conidia* (spores) from soil or organic debris.
• Dermal contact with contaminated soil (rare).
• Possible sexual transmission (suggested but not confirmed).
Environmental Reservoir
•_______ thrives in wooded areas with damp soil, particularly near lakes, rivers, and waterways.
• Risk Factor: Soil disturbance (excavation, construction) in endemic areas.
Blastomyces
Infection Initiation
• Inhaled conidia transform into thick-walled, broad-based budding yeasts in the lungs.
• yeast form resists phagocytosis by alveolar macrophages, promoting survival and dissemination.
Blastomyces
Conidia are inhaled and phagocytosed by alveolar macrophages, where they convert to intracellular yeasts.
Histoplasmosis
• Severe disease: Chronic pneumonia (resembles TB), dissemination to liver, spleen, and bone marrow, causing hepatosplenomegaly, pancytopenia, and weight loss.
• Risk group: HIV/AIDS patients (disseminated histoplasmosis is an AIDS-defining illness).
Histoplasmosis
• Inhaled conidia transform into yeasts with multiple budding (“pilot’s wheel” appearance).
Paracoccidioidomycosis
• Severe cases: Chronic pulmonary infection, mucocutaneous ulcers, and lymphadenopathy.
• Endemic in South America, primarily affecting male agricultural workers (estrogen inhibits transformation of conidia into yeast, explaining male predominance).
Paracoccidioidomycosis
Inhaled conidia develop into intracellular yeasts that multiply within macrophages
Talaromycosis
• Disseminated disease: Fever, weight loss, skin lesions, hepatosplenomegaly, and pancytopenia.
• Occurs in immunocompromised hosts, especially HIV/AIDS patients in Southeast Asia.
Talaromycosis
Newly emerging systemic fungal infection, primarily affecting immunocompromised individuals.
Emergomycosis
• Causes disseminated disease with fever, skin lesions, pulmonary and bone marrow involvement.
• Endemic in multiple continents (Asia, Europe, Africa, North America)
Emergomycosis
Infection Initiation
• Inhaled conidia transform into thick-walled, broad-based budding yeasts in the lungs.
• yeast form resists phagocytosis by alveolar macrophages, promoting survival and dissemination.
Blastomycosis
• Often asymptomatic or self-limited.
• Mild cases: Flu-like symptoms (fever, chills, cough, myalgia).
• Severe cases: Chronic pneumonia with pulmonary infiltrates, cough, weight loss, and night sweats.
Pulmonary Blastomycosis (79% of cases)
Histopathology:
• Pyogranulomatous reaction (mixture of neutrophils and granulomas).
• Noncaseating granulomas (resembles sarcoidosis).
Pulmonary Blastomycosis (79% of cases)
Animal Susceptibility
• Dogs are highly susceptible, particularly Bluetick Coonhounds.
Blastomycosis
BLASTOMYCOSIS
Direct Microscopy (Specimen Examination)
• Samples:
• Stains:
• KOH prep, cytology, or histology (detect yeast).
• H&E stain (400× magnification):
• Large thick-walled yeasts (8–15 µm).
• Broad-based budding (bud enlarges to nearly the same size as parent yeast before detaching).
Sputum, BAL (bronchoalveolar lavage), abscess fluid, or biopsy from granulomatous nodules.
BLASTOMYCOSIS
Culture Identification
Mold Form (25-30°C) on WHAT AGAR???:
• Grows in_____(how long??)
• Color or colonies???
SDA (Sabouraud Dextrose Agar)
7–14 days
Cottony white to brownish mold colonies
Culture Identification
LPCB mount:
• Branching hyphae.
• Spherical, ovoid, or piriform-shaped conidia (3–5 µm) on thin stalks.
• Larger chlamydospores (7–18 µm) may also be present.
BLASTOMYCOSIS
BLASTOMYCOSIS
________(culture extract antigens) – used in skin tests, but lacks specificity.
• Complement Fixation (CF) Test:
• High titers (_____) in progressive or disseminated disease.
• Limited diagnostic value due to cross-reactivity.
Blastomycin
≥1:16
BLASTOMYCOSIS
________ of B. dermatitidis – more reliable in:
• Immunodiffusion (ID) test.
• Enzyme Immunoassay (EIA) – 92% specificity.
Antigen A
BLASTOMYCOSIS
• Highly sensitive, but ***cross-reacts with Histoplasma*** due to galactomannans in the cell wall.
Urine Antigen Testing (Blastomyces Ag Test):
BLASTOMYCOSIS
• Virulence factor. • Inhibits TNF (tumor necrosis factor) release, reducing immune response
BAD1 Protein (Blastomyces Adhesin 1):
