Systemic Mycoses Lecture Notes PDF

MT 6322: MYCOLOGY AND VIROLOGY LECTURE Course Instructors: Assoc. Prof. Jocelyn D. Domingo, RMT, MSc A.Y. 2024-2025, Term 1...

MT 6322: MYCOLOGY AND VIROLOGY LECTURE Course Instructors: Assoc. Prof. Jocelyn D. Domingo, RMT, MSc A.Y. 2024-2025, Term 1 SYSTEMIC MYCOSES ✄ Usually enter the body via the respiratory tract and primarily cause pneumonia, but all can become systemic and produce secondary skin or mucosal lesions through hematogenous spread. AGENTS OF SYSTEMIC MYCOSES Blastomyces dermatitidis Coccidioides spp. (C. immitis, C. posadasii) Histoplasma capsulatum Paracoccidioides brasiliensis LEGEND BLASTOMYCOSIS BOOK / RESOURCES OTHER FACTS & DETAILS TO NOTE Causative: Blastomyces dermatitidis ✄ The skin is the most common extrapulmonary site ✄ ✎ of Blastomyces infection. ○ Well-circumscribed tender nodules, ulcers, PRE-TEST or plaques can occur anywhere on the body, often on the exposed areas of the head, TRUE OR FALSE neck, or extremities. 1. Any fungus, in an immunocompromised host, has the potential to become invasive and disseminate to sites far removed from the portal of entry. 2. The teleomorph of H. capsulatum is named Ajellomyces dermatitidis. 3. Histoplasmosis is also known as Spelunker's Disease 4. People get paracoccidioidomycosis after breathing in the fungus Paracoccidioides from the environment in certain parts of Central and South America. MOT: Inhalation 5. Vaccine is already available for Valley fever. ○ Causes Blastomycosis – a chronic infection with granulomatous and suppurative SYSTEMIC MYCOSES lesions that is initiated in the lungs Fungal infections which can overcome the ○ Most prevalent in middle-aged men physiological and cellular defenses of the normal ○ Symptoms are often similar to flu human host Infection occurs by inhalation of airborne conidia PATHOGENESIS Fungal infection of internal organs S/S: fever, malaise, night sweats, cough, myalgias ✄ They are known as dimorphic fungi because they When dissemination occurs, skin lesions on the exhibit different morphologies at different exposed surfaces → ulcerated granulomas with temperatures, existing as molds in the environment advancing border and central scarring → border at 22C to 30C but as yeats at body temperature. with abscesses and sharp, sloping edge 1  RISK AND PREVENTION 1. Who gets blastomycosis? 2. Is blastomycosis contagious? 3. Can my pets get blastomycosis? 4. How can I prevent blastomycosis? TREATMENT Amphotericin B Itraconazole CLINICAL TYPES OF BLASTOMYCOSIS 1. Pulmonary 2. Cutaneous 3. Disseminated Branching hyphae bearing spherical, ovoid, or piriform conidia (3–5 μm in diameter) on slender terminal or lateral conidiophores LABORATORY DIAGNOSIS Specimen: Sputum, Pus, Exudates, Urine, Biopsies from Lesion 1. Microscopic: - Round, multinucleated, budding cells with double refractile wall 2. Cultivation in SDA ✄ Silver and periodic acid–Schiff stains Image: cutaneous abscess are helpful in identifying the organisms that will also grow on SDA. Microscopic exam: broadly attached buds on ✄ Occationally cultures of Blastomyces thick-walled yeast cells (sputum, pus, exudates, and H. capsulatum are recovered in as urine) short a time as 2 to 5 days when many organisms are present in the clinical specimen. - White or brownish colonies 3. Cultivation in Enriched BAP - Wrinkled, waxy and soft colonies 4. Serological tests - CFT, immunodiffusion tests Left: mold form Right: Yeast form (broad base budding yeast) 2  COCCIDIOIDOMYCOSIS Causative agents: Coccidioides immitis, Coccidioides posadasii ○ C. immitis - more common among the two spp. ✄ Lesions can be maculopapular verrucous, ulcerated, or fluctuant abscesses. ✄ Coccidioides is highy contagious, so the laboratory should be notified that it might be present when clinical material is sent for cuture. CLINICAL FEATURES OF COCCIDIODOMYCOSIS Many develop influenza like fever Allergic manifestations