Dermatophytes Overview

Dermatophytes belong to the phylum Ascomycota, class Eurotiomycetes, order Onygenales, and family Arthrodermataceae.

Dermatophyte colonies can be powdery, velvety, cottony, or fluffy, and exhibit varying colors depending on the species.

Dermatophytes feature specialized structures such as chlamydoconidia and spiral hyphae.

<p>Keratinase is a virulence factor that allows dermatophytes to break down keratin, facilitating their growth and invasion.</p> Signup and view all the answers

<p>Dermatophytes are responsible for skin infections known as 'ringworm' or tinea.</p> Signup and view all the answers

<p>Dermatophytes typically exhibit septate hyphae, macroconidia, and microconidia.</p> Signup and view all the answers

<p>'Keratinophilic' refers to dermatophytes' affinity for keratin, as they thrive on keratin-containing tissues.</p> Signup and view all the answers

<p>Dermatophytes primarily inhabit the skin, hair, and nails of humans and animals.</p> Signup and view all the answers

<p>The genome sizes range from 2.25 Mb to 24.1 Mb.</p> Signup and view all the answers

<p>E.floccosum has haploid conidia that are uninucleated and multinucleated hyphae.</p> Signup and view all the answers

<p>Anthropophilic dermatophytes live on humans.</p> Signup and view all the answers

<p>E.floccosum colonies are greenish-brown or khaki, have a suede-like surface, and may develop white tufts as they age.</p> Signup and view all the answers

<p>E.floccosum is known to cause Tinea pedis, Tinea cruris, Tinea corporis, and Onychomycosis.</p> Signup and view all the answers

<p>The macroconidia of E.floccosum are smooth and have thick walls.</p> Signup and view all the answers

<p>The reverse pigments of E.floccosum colonies generally display a yellowish-brown color.</p> Signup and view all the answers

<p>Unlike other dermatophytes, E.floccosum does not invade hair in vivo.</p> Signup and view all the answers

<p>Chlamydospores are survival structures formed in older cultures that help Epidermophyton floccosum withstand adverse conditions.</p> Signup and view all the answers

<p>The primary symptom was nail lesions, particularly affecting the left big toe, which showed mild inflammation and thickening of the nail bed.</p> Signup and view all the answers

<p>Diagnostic methods included scraping scales from the affected nail for microscopic examination with 20% KOH and culturing samples on Sabouraud dextrose agar.</p> Signup and view all the answers

<p>The colonies developed beige, velvety appearances, and microscopic analysis revealed septate hyphae and club-shaped macroconidia.</p> Signup and view all the answers

<p>20% potassium hydroxide (KOH) is used to clear keratin in nail samples, allowing for the visualization of fungal elements under a microscope.</p> Signup and view all the answers

<p>Treatment included topical antifungals such as 8% ciclopirox and oral terbinafine at 250 mg as first-line therapy.</p> Signup and view all the answers

<p>The absence of microconidia indicates a specific morphological characteristic that differentiates E. floccosum from other dermatophytes.</p> Signup and view all the answers

<p>Prolonged use of closed shoes creates a warm and damp environment that promotes fungal growth, increasing the risk of tinea corporis.</p> Signup and view all the answers

<p>Colonies appear yellowish to brownish with a granular to cottony surface.</p> Signup and view all the answers

<p>Macroconidia are multiseptate with thick rough cell walls, typically clavate, fusiform, or spindle-shaped.</p> Signup and view all the answers

<p>Numerous annular erythematous plaques developed across her body, especially on the face, neck, and trunk.</p> Signup and view all the answers

<p>Direct microscopic examination and fungal cultures confirmed the presence of Microsporum canis.</p> Signup and view all the answers

<p>The family was treated with itraconazole (200 mg/d) for 1 month.</p> Signup and view all the answers

<p>It suggests that pets may also be infected with Microsporum canis, contributing to the outbreak.</p> Signup and view all the answers

<p>RAPD analysis confirmed that the five isolated strains were the same fungal species.</p> Signup and view all the answers

<p>The lesions resolved three months after the completion of treatment.</p> Signup and view all the answers

<p>The common skin lesions include inflammatory, eczematous lesions with erythema and scaling.</p> Signup and view all the answers

<p>Trichophyton spp. colonies appear white to cream in color, with a powdery to granular texture, and a reverse pigment that ranges from yellow-brown to reddish-brown.</p> Signup and view all the answers

<p>Macroconidia in Trichophyton spp. are thin- or thick-walled, clavate to fusiform in shape, and may be borne laterally directly on the hyphae or on short pedicels.</p> Signup and view all the answers

<p>The presence of microconidia is a distinguishing feature of Trichophyton, as Epidermophyton lacks these structures.</p> Signup and view all the answers

<p>The girl exhibited an itchy, erythematous, and annular plaque on her right face.</p> Signup and view all the answers

<p>Sabouraud's dextrose agar (SDA) was used for culturing the suspected Trichophyton infection.</p> Signup and view all the answers

<p>Lactophenol cotton blue staining revealed the filamentous and spiral hyphae.</p> Signup and view all the answers

<p>Microconidia of Trichophyton mentagrophytes were observed in a grape-like arrangement, inserting laterally and terminally at the hyphae.</p> Signup and view all the answers

<p>The tinea faciei was caused by the fungus Trichophyton benhamiae.</p> Signup and view all the answers

<p>Terbinafine (oral 125 mg/d) and sertaconazole nitrate cream (topical, twice daily) were the treatments given.</p> Signup and view all the answers

<p>There was significant improvement in the skin lesions, with complete resolution of the plaque and residual erythema.</p> Signup and view all the answers

<p>The diagnosis was established through molecular sequencing tests that were consistent with reference strains of T.benhamiae.</p> Signup and view all the answers

<p>The annular plaque measured approximately 3 cm × 5 cm.</p> Signup and view all the answers

<p>The symptoms included an annular plaque with erythema covered with scales and crusts.</p> Signup and view all the answers

<p>The case was first reported in China.</p> Signup and view all the answers

<p>The oral treatment was 125 mg/d of terbinafine, and the topical treatment was sertaconazole nitrate cream applied twice daily.</p> Signup and view all the answers