Dermatophytes, Medically Important Yeasts, and Mucorales

Flashcards covering the taxonomy, clinical manifestations, diagnosis, and treatment of dermatophytes, medically important yeasts (Candida, Cryptococcus), and Mucorales based on the lecture notes.

Anthropophilic

A category of dermatophyte characterized by a human reservoir.

Zoophilic

A category of dermatophyte characterized by an animal reservoir.

Geophilic

A category of dermatophyte characterized by a soil or environmental reservoir.

Arthroderma

The genus to which most teleomorph (sexual) forms of dermatophytes belong.

Tinea pedis

The clinical term for a dermatophyte infection of the foot, commonly known as athlete’s foot.

Tinea unguium (Onychomycosis)

A dermatophyte infection of the nails.

Arthroconidia

Fungal spores formed during the fourth phase of dermatophyte pathogenicity for onward infection.

Wood’s lamp

A diagnostic tool used to identify certain dermatophyte infections by looking for characteristic blue-green fluorescence.

Trichophyton indotineae

An emerging anthropophilic dermatophyte (genotype VIII) endemic across Asia and increasing in the UK, noted for high resistance to terbinafine (75% of UK isolates).

Trichophyton mentagrophytes genotype VII

An emerging dermatophyte associated with sexual transmission and more severe, rapidly spreading inflammatory plaques or ulcers.

Candida auris

An emergent nosocomial pathogen first reported in Japan in 2009; it is often multidrug resistant, lacks hyphal forms, and is historically difficult to identify using biochemical tests.

Candidalysin

A factor contributing to host cell damage during Candida pathogenesis.

Beta-D-glucan assay

A non-specific test used to detect invasive Candida infections, though it is not effective for detecting Cryptococcus (very low levels) or Mucorales (does not produce it).

Cryptococcus neoformans

A globally dominant basidiomycete yeast often associated with avian excreta and serious meningitis in immunocompromised patients.

Neurotropism

The tendency of a pathogen, such as Cryptococcus, to disseminate to and infect the central nervous system.

CrAg test

A rapid cryptococcal antigen test performed on serum or CSF, used as the first test for high-clinical suspicion of infection.

India ink test

A diagnostic method used to visualize the polysaccharide capsule of Cryptococcus in CSF or culture.

CGB media

A specialized medium used to differentiate Cryptococcus gattii (which triggers a deep blue color) from Cryptococcus neoformans.

Mucorales

An order of thermotolerant, rapidly growing fungi (including Rhizopus and Mucor) that are primarily opportunistic pathogens and cause severe infections like rhinocerebral mucormycosis.

Lid lifters

A descriptive term for Mucorales cultures in a petri dish due to their rapid growth and expansive aerial mycelia invading the air-space.

Deferoxamine

An iron chelator that acts as an extrinsic risk factor for mucormycosis by increasing iron availability for the fungus.

Angioinvasion

The process by which Mucorales hyphae adhere to and invade blood vessels, blocking them and leading to tissue necrosis.

Calcofluor white

A stain used in direct microscopy to identify broad, infrequently septate hyphae branching at $90^\circ$ in mucoraceous mould infections.

Rhizoids

Root-like microscopic features found in some Mucorales; in Rhizopus spp., they are often pigmented.