Antifungal+Lecture_24_25

Antifungal Infections

Dr. Kassim Adebambo

Learning Outcomes

  • Identify the structural features of fungi (therapeutic targets).

  • Gain an understanding of different types of fungi.

  • Explore examples of fungal infections.

  • Pharmacology of antifungal agents.

  • Clinical applications of antifungal drugs.

Major Features of Fungi

  • Characteristics:

    • Non-motile eukaryotic heterotrophes.

    • Cell wall composed of chitin.

    • Morphological characteristics include:

    • Hyphae

    • Mycelium

    • Co-exist with humans as commensals but may also be saprophytic/parasitic.

    • Approx. 50 species are pathogenic.

  • Cellular Structures:

    • Hyphae: Long, branching filamentous structures.

    • Mycelium: Networks formed by hyphae.

    • Spores: Asexual reproductive units.

    • Septa: Cross-walls in hyphae that divide them into compartments.

Structural Features of Fungi

  • Cell Wall Structure:

    • Layer composed of mannoproteins.

    • Layers of β\beta-glucans (specifically β\beta-1,3-glucan).

    • Layer of chitin.

    • Ergosterol in the cell membrane.

Types of Fungi and Related Infections

  • Yeasts (e.g., Cryptococcus neoformans):

    • Characteristics: Unicellular.

    • Infections: Meningitis.

    • Treatment: Amphotericin B + Flucytosine.

  • Yeast-like Fungi (e.g., Candida albicans):

    • Produce filaments resembling mycelium.

    • Infections:

    • Thrush (oral candidiasis).

      • Treatment: Azoles, Nystatin.

    • Systemic candidiasis.

      • Treatment: Amphotericin B, Azoles, Caspofungin.

  • Moulds (e.g., Aspergillus fumigatus, dermatophytes):

    • Characteristics: Filamentous, multicellular.