MYCOLOGY MCQs — Complete Bank

================================================================ MEDICAL MICROBIOLOGY — MEDICAL MYCOLOGY Mount Kenya University MBMM 3300 School of Health Sciences ================================================================ This guide covers all examined topics in Medical Mycology as tested across MKU past papers and CATs from 2017/2018 to 2021/2022. Each section is organised by topic, with the exact exam question followed by concise point-form answers structured for quick revision. Papers referenced: 2021/2022 2018/2019 2017/2018 Main Exams Medical Mycology CATs ================================================================ TOPICS COVERED ================================================================ 1. True Pathogenic Fungi vs Opportunistic Fungi 2. Disease Name Matching 3. Risk Factors for Fungal Infections 4. Virulence Factors of Fungi 5. Eumycetoma vs Actinomycetoma 6. Histoplasmosis 7. Cryptococcosis 8. Dimorphism in Systemic Fungi 9. Paracoccidioidomycosis 10. Tinea Versicolor 11. Tinea Nigra Palmaris 12. Five Types of Dermatophytoses 13. Epidermophyton and Microsporum 14. Modes of Action of Antifungals 15. Candidiasis 16. Mycetoma 17. Systemic Mycoses — Laboratory Diagnosis 18. Characteristics of Systemic Mycoses 19. Classes of Fungi Based on Reproduction 20. Fungi with Special Characteristics ================================================================ CONTENT ================================================================ ---------------------------------------------------------------- 1. TRUE PATHOGENIC FUNGI VS OPPORTUNISTIC FUNGI ---------------------------------------------------------------- Question: In what respect do mycoses caused by true pathogenic fungi differ from mycoses caused by fungi associated with opportunistic infections? What are the general consequences of these infections to the human host? True pathogens infect HEALTHY, IMMUNOCOMPETENT individuals with normal host defenses Opportunistic fungi only cause disease in IMMUNOCOMPROMISED hosts — HIV/AIDS, transplant recipients, diabetics, patients on steroids True pathogens are GEOGRAPHICALLY RESTRICTED e.g. Histoplasma capsulatum, Coccidioides immitis Opportunistic fungi are UBIQUITOUS in the environment e.g. Candida, Aspergillus, Cryptococcus True pathogens have defined virulence mechanisms independent of host immune status CONSEQUENCES: chronic pulmonary disease, disseminated infection, CNS involvement, septicaemia, death in severe cases ---------------------------------------------------------------- 2. DISEASE NAME MATCHING ---------------------------------------------------------------- Question: Match the common name of the disease with the clinical name Darling's disease -- Histoplasmosis Valley fever -- Coccidioidomycosis South American/Brazilian Blastomycosis -- Paracoccidioidomycosis Mycotic Mycetoma -- Pseudoallescheriasis Balanitis -- Candidiasis of the penis ---------------------------------------------------------------- 3. RISK FACTORS FOR FUNGAL INFECTIONS ---------------------------------------------------------------- Question: Outline risk factors to fungal infections HIV/AIDS and other immunodeficiencies Prolonged or broad-spectrum antibiotic use — disrupts normal protective flora Corticosteroid or immunosuppressive therapy Diabetes mellitus — impairs phagocyte function Haematological malignancies e.g. leukaemia, lymphoma Organ or bone marrow transplantation Indwelling catheters and prosthetic devices Extremes of age — neonates and elderly Malnutrition and chronic illness ---------------------------------------------------------------- 4. VIRULENCE FACTORS OF FUNGI ---------------------------------------------------------------- Question: Explain any two virulence factors used by fungi to cause diseases in the host 1. CAPSULE PRODUCTION — e.g. Cryptococcus neoformans Polysaccharide capsule resists phagocytosis Inhibits complement activation Suppresses T-cell mediated immunity 2. DIMORPHISM Switch between mould (environmental) and yeast (tissue) form Yeast form resists host defenses and persists inside macrophages e.g. Histoplasma, Blastomyces, Coccidioides Other virulence factors: Melanin production — protects against oxidative killing by phagocytes Enzyme secretion — proteases and lipases break down host tissue Biofilm formation — protects Candida from antifungals and immune attack ---------------------------------------------------------------- 5. EUMYCETOMA VS ACTINOMYCETOMA ---------------------------------------------------------------- Question: Compare Eumycetoma and Actinomycetoma FEATURE EUMYCETOMA ACTINOMYCETOMA ------------------+-------------------------+--------------------- Causative agent True fungi e.g. Filamentous bacteria Madurella mycetomatis e.g. Nocardia, Actinomadura Grain colour Black or white White, yellow, or red Grain texture Hard, compact Soft, friable Treatment Antifungals — Antibiotics — ketoconazole, TMP-SMX, voriconazole streptomycin Response Poor Better response --