The Fungi

Types of macroscopic fungi

Mushrooms, puffballs, gill fungi

Types of Microscopic fungi

Molds, yeasts

Types of fungal forms

Yeast cell, Hyphae, Dimorphic, Pleomorphic

Thermally Dimorphic

A mold when growing saprophytically at 25 to 30° C and as a yeast at 37° C in animal tissue

Yeast Cell

Round/Oval shape that goes through asexual reproduction

Hyphae

Long threadlike cells found in filamentous

Dimorphic

Some fungi can take either yeast cell or hyphae forms

Pleomorphic

Can alter size or shape according to the environment

Mycelium

Woven, intertwining mass of hyphae which makes up body or colony of mold

Septa

Hyphae divided into segments or cross wall

Spores

Fungal reproductive bodies

Fungi cell envelope

Have cell walls containing chitin polysaccharides

Asexual Reproduction (cloning)

• Haploid stage

• Growth of existing hyphae

• Fragmentation: separated piece of mycelium

• Forms new colony

Sexual Reproduction

• Brief diploid stage

• Spore formation

Mycoses

Fungal infection

Disease Mechanisms

1. Allergic responses

2. Mycotoxins

3. Mycoses (superficial, subcutaneous, systemic)

Superficial Myocoses

Colonize hair, skin, nails (only surface areas)

Subcutaneous Mycoses

Colonize deeper layers of skin usually from implantation into skin through trauma

Systemic Mycoses

Infection by inhaling spores which can cause growth on internal organs and skin lesions (Completely Opportunistic)

Keratinophibic

Feeds on keratin in hair, skin, and nails

Candida albicans

1. Normal gut flora, nosocomial

2. Pleomorphic

   • Outside body: Yeast like

   • Inside body: mold like

3. Candidiasis: fungal infection caused by yeast (Thrush)

4. Superficial

Trichophyton spp

1. Contract with spores through direct or indirect contact

2. Keratinaphobic mold

3. Multiple species

   1. Tinea pedis (Athletes Foot)

      • Dermatophytosis

      • Indirect human to human

   2. Tinea corporis (Ringworm)

      • On body

   3. Tinea cruris (Jock Itch)

      • Highly opportunistic

4. Superficial

Sporathrix schenckii

1. Contact with spores into skin

2. Thermally dimorphic

3. Sporotrichosis (Rose Gardeners Disease)

4. Subcutaneus

Fonsecaea pedrosoi

1. Implantation of spores usually through thorns or splinters

2. Mold

3. Chromoblastomycosis: skin ulceration

4. Subcutaneous

Histoplama capsulatum

1. Breath in spores from dried bird/bat poop

2. Thermally dimorphic

3. Histoplasmosis: skin lesions (upper lip), cough, flu-like symptoms

4. Systemic

Coccidioides immitis

1. Soil disrupted by rain, wind, construction

2. Thermally dimorphic

3. Coccidiomycosis (Vally fever): lesions, bronchitis or pneumonia, fever

Cryptococcus neoformans

1. Soil

   • Breathing it in

   • Cutaneous

2. Thermally dimorphic

3. Cryptococcosis: meningitis