OPPORTUNISTIC MYCOSES @ Fail to induce disease in most normal persons but may do so in those with impaired host defenses (AIDS). @ They include: # Candida.

OPPORTUNISTIC MYCOSES

@ Fail to induce disease in most normal persons but may do so in those with impaired host defenses (AIDS).

@ They include: # Candida # Cryptococcus # Aspergillus # Mucor and Rhizopus

CANDIDA

@ C. albicans causes thrush, vaginitis, and chronic mucocutaneous candidiasis.

Properties:

@ C albicans is an oval yeast-like fungus with a single bud

@ Part of normal flora of URT, GIT and female genital tracts.

@ In tissues appears as yeasts or as pseudohyphae-not true hyphae.

@ Sugar fermentation differentiate it from C. tropicalis, C. krusei, and C. glabrata.

Transmission :

@ As a member of normal flora, it is not transmitted.

Diseases:

@ C. albicans produces:

* Mouth : white patches (thrush).

* Vulva and vagina: itching & vaginal discharge, favored by high pH, diabetes, or antibiotics.

* Fingers & nails: causes paronychia

* Drug abusers: causes endocarditis

Laboratory Diagnosis:

@ In exudates or tissues, budding and pseudohyphae are seen microscopically.

@ Such specimens grow yeast cells when cultured on Sabouraud's medium

@ Germ tubes form in serum at 37ºC, distinguish C. albicans from most other Candida species .

@ Chlamydospores are formed by C. albicans only .

@ Serologic testing is rarely helpful.

@ Skin tests are positive in normal adults & used as an indicator of good cellular immunity.

@ A person who does not respond to Candida antigens in skin test has deficient cell-mediated immunity.

Treatment & Prevention:

@ Candida infections are treated by fluconazole, nystatin, or ketoconazole, @ Amphotericin B is given for severe Candida infections

@ Thrush is prevented by nystatin .

@ There is no vaccine.