Systemic mycoses
 Systemic mycoses - fungal infections
that affect internal organs & tissues.
Acquired via inhalation of fungal spores.
 Caused by dimorphic fungi which exist
as molds (in environment) & transform
into yeast or spherules (in human
tissues)
 Important systemic mycoses are
1.Histoplasmosis
2.Blastomycosis
3.Coccidioidomycosis
4.Paracoccidioidomycosis
5. Talaromycosis (formerly penicilliosis)
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Histoplasmosis
 Caused by Histoplasma capsulatum
 Found in soil contaminated with bird or bat droppings,
endemic in the Ohio & Mississippi River valleys (USA) & parts of
Latin America.
Clinical features: Pulmonary infections
(Acute, chronic & Disseminated)
Acute: flu-like symptoms, fever, cough.
Chronic: similar to tuberculosis.
Disseminated: affects the liver, spleen, and bone marrow,
especially in immunocompromised patients.
 Treatment: Itraconazole (localized infection);Amphotericin B
followed by Itraconazole (severe / disseminated infection)
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Blastomycosis
 Caused by Blastomyces dermatitidis
 Endemic in North America,
particularly the Great Lakes, Ohio, &
Mississippi River valleys
Clinical features:
 Pneumonia-like lung infection.
 Cutaneous involvement with
ulcerative skin lesions.
 Bone & CNS involvement in
disseminated disease
 Treatment:
 Itraconazole
(localized
infection);
Amphotericin
B
followed
by
Itraconazole (severe / disseminated
infection)
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Coccidioidomycosis (Valley Fever)
 Caused by Coccidioides immitis & C. posadasii
 Found in desert regions of the
southwestern USA, Mexico, & South
America
Clinical features:
Flu-like symptoms with fever, cough,
& arthralgia.
Severe cases: meningitis, skin nodules,
bone involvement.
Treatment: Fluconazole
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Paracoccidioidomycosis
 Caused by Paracoccidioides brasiliensis
 Restricted to Central & South America,
particularly Brazil.
 Clinical features:
Chronic progressive lung infection.
Mucocutaneous lesions, lymphadenopathy.
Infection may disseminate to liver, spleen, & CNS.
Treatment: Itraconazole (localized infection);
Amphotericin B followed by Itraconazole (severe /
disseminated infection)
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Talaromycosis (formerly penicilliosis)
 Caused by Talaromyces marneffei
 Found in Southeast Asia & South
China, primarily affecting HIV/AIDS
patients
 Clinical features:
Opportunistic infection in HIV/AIDS
patients. Fever, weight loss,
lymphadenopathy, skin lesions.
 Treatment: Amphotericin B followed by itraconazole
Systemic mycoses - pathogenesis
1. Inhalation of spores –inhalation of
fungal spores from soil or airborne
particles is the primary mode of infection.
2. Transformation to pathogenic form –
Dimorphic fungi converts to yeast (or
spherules in the case of Coccidioides) in
the host’s tissues.
3. Immune evasion – Fungi resist the
phagocytosis & modulate the immune
response.
4. Dissemination – Fungi spread to
multiple organs (lungs, skin, bones & CNS)
in immunocompromised individuals
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Systemic mycoses - diagnosis
Direct examination of skin scrapings
1. Microscopy & Staining: Direct examination
using potassium hydroxide (KOH), Giemsa, or
Periodic acid–Schiff (PAS) stains.
2.Culture: Growth on SDA.
3.Serology: Detection of specific fungal
antigens (e.g., histoplasmin, coccidioidin).
Skin lesion, Fungal growth on SDA
4.Molecular Tests: PCR for rapid detection.
5.Histopathology: Tissue biopsy with fungal
stains such as Gomori methenamine silver
Histopathological microscopic examination
(GMS) or PAS.
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Systemic mycoses – prevention & control
Avoid exposure to endemic areas
(e.g., caves, bird roosts, soil disturbances).
1.
2. Use of masks in high-risk areas.
3. Prophylactic antifungals in severely
immunocompromised patients
(e.g., HIV/AIDS, transplant recipients).
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Opportunistic Mycoses
 Opportunistic mycoses are
Important opportunistic mycoses
are
infections caused by nonpathogenic fungi that take
advantage of weakened host
1.Candidiasis
defenses.
 Occurs in individuals with
2.Cryptococcosis
compromised immune
3.Aspergillosis
systems (HIV / AIDS patients,
Cancer, Organ transplants, 4.Mucormycosis
diabetes) & those
undergoing
immunosuppressive therapy. 5.Pneumocystis Pneumonia
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candidiasis
Caused by Candida albicans (most
common), C. glabrata, C. tropicalis,
etc.,
Clinical manifestations: Candidiasis –
Oropharyngeal (thrush), Esophageal,
Vaginal & Invasive (affects internal
organs – liver, spleen & kidney) and
candidemia.
Risk Factors: Antibiotic use, diabetes,
immunosuppression, central venous
catheters
Diagnosis: KOH mount, Gram stain,
culture, PCR, β-D-glucan test
Treatment: Fluconazole,
Echinocandins (caspofungin),
Amphotericin B
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Cryptococcosis
Caused by Cryptococcus neoformans &
C. gattii.
Clinical manifestations: Meningitis (in AIDS
patients), Pulmonary cryptococcosis
Risk Factors: HIV/AIDS, organ transplant,
chronic steroid use
Diagnosis: India ink staining, Cryptococcal
antigen test, CSF culture
Treatment: Amphotericin B + flucytosine,
followed by fluconazole
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Aspergillosis
Caused by Aspergillus fumigatus (most
common), A. flavus, A. niger
Clinical manifestations: Aspergillosis
(Allergic bronchopulmonary & Invasive) &
Aspergilloma (fungus ball in lungs)
Risk Factors: Neutropenia, lung disease,
stem cell transplant
Diagnosis: Galactomannan assay, fungal
culture, chest CT scan
Treatment: Voriconazole, amphotericin B,
echinocandins
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Mucormycosis
Caused by Mucor spp., Rhizopus spp.,
Clinical manifestations: Mucormycosis –
(Rhinocerebral, Pulmonary, Gastrointestinal
& cutaneous)
Risk Factors: Uncontrolled diabetes
(especially ketoacidosis), neutropenia, iron
overload
Diagnosis: Direct microscopy (KOH), culture,
histopathology
Treatment: Amphotericin B, surgical
debridement, posaconazole or isavuconazole
for maintenance
Rhino cerebral mucormycosis
Cutaneous mucormycosis
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Pneumocystis Pneumonia - PCP
Caused by Pneumocystis jirovecii.
Clinical manifestations: Severe pneumonia
in immunocompromised individuals.
Risk Factors: AIDS
(CD4 <200 cells/mm³), chemotherapy, organ
transplant.
Diagnosis: Giemsa or silver stain, PCR,
bronchoalveolar lavage (BAL).
Treatment: Trimethoprim-sulfamethoxazole
(TMP-SMX), pentamidine (alternative).
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Opportunistic mycosis - prevention
1. Antifungal prophylaxis in high-risk patients.
2. Personal Hygiene & infection control in hospitals.
3. Avoid fungal exposure.
4. Diabetes control.
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