Summary of Mycosis: Fungal Diseases of Humans

Mycosis - Fungal Diseases of Humans

Useful Properties of Fungi

  • Source of food (e.g., mushrooms)

  • Fermentation (e.g., Saccharomyces species)

  • Antibiotic production (e.g., Penicillin from Penicillium notatum)

Characteristics of Fungi

  • Over 100,000 known species, with about 100 being human/animal pathogens

  • Can be saprophytes, parasitic, or commensal organisms

Importance of Studying Fungal Pathogens

  • WHO fungal priority pathogens list includes critical and high priority pathogens like Cryptococcus neoformans and Aspergillus fumigatus.

  • ~6.5 million cases of invasive fungal infections with ~3.8 million deaths yearly.

  • Factors for increased infections: aging population, medical advances, antifungal resistance.

Learning Objectives

  • Understand types of fungal infections, virulence factors, and antifungal therapy targets (e.g., Candida albicans, Cryptococcus neoformans).

Fungi as Pathogens

  • Opportunistic Pathogens: E.g., Candida albicans, Aspergillus fumigatus.

  • Primary Pathogens: E.g., Histoplasma capsulatum, Coccidioides immitis.

Risk Factors for Fungal Infections

Immunologic Factors

  • HIV/AIDS (loss of CD4+ T cells)

  • Neutropenia

  • Immunosuppressive therapies

Non-Immunologic Factors

  • Disruption of skin barriers

  • Antibiotic use disrupting microbiota

  • Environmental exposure to fungal spores

  • Diabetes and hormonal factors

Fungal Pathogenesis

  • Virulence intensity and factors that increase virulence.

Specific Fungal Pathogens and Diseases

  • Candida albicans: Skin infections, systemic disease, nosocomial pathogen.

  • Aspergillus fumigatus: Causes aspergillosis.

  • Pneumocystis jirovecii: AIDS defining lung infection.

  • Histoplasma capsulatum: Causes histoplasmosis, endemic in Ohio River Valley.