Fungal Skin Infections: Trichophyton & Epidermophyton Species
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It is 2 of the three major genera on which they are responsible for dermatophytosis, hence they are called Dermatophytes. you can see here their basic background and different morphological characteristics. This presentation was derived from Microbiology 4 books. Bailley's Scott Mahon Alcamo Jaweitz
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Fungal Skin Infections: Trichophyton & Epidermophyton Species
- 1. Trichophyton & Epidermophyton • PRINCESS ALEN AGUILAR
- 2. CONTENTS • Trichophyton – With Conidia • T. mentagrophytes • T.rubrum • T. tonsurans – Only Hyphae • T. violaceum • T.shoenleinii • T. verrucosum • Epidermophyton floccosum
- 3. Trichophyton • Sexual stage Arthroderma under Ascomycota • Most important and common causes of infections of the feet and nails; • they may be responsible for tinea corporis, tinea capitis, tinea unguium, and tinea barbae. • Primarily in adults • Most cosmopolitan species are anthropophilic, or “human-loving”; few are zoophilic • No fluorescing hair under Wood's lamp
- 4. Trichophyton • produces bote micro/macroconidia • Few or no macroconidia – Thin ans smooth – fusiform or cylindrical with 2-12 cells per conidium – Elongated, few or absent This micrograph reveals both a macroconidium and some microconidia of the fungus Trichophyton rubrum var. rodhaini.
- 5. Trichophyton • Many Microconidia –Globose, pyriform or clavate –Borne on 2 patterns • En thryses: sleevelike arrangement around the hyphae • En grappe: in clusters (Branches of grapes) –Predominant than Macroconidia
- 6. Trichophyton mentagrophytes • rapidly growing and distributed worldwide • one of the most common species recovered in the lab • T. mentagrophytes perforates hair hence can be used as criterion when have difficulties in distiguishing it from T.rubrum • can produce both micro/marcoconidia • responsible for Tinea pedis, Tinea cruris, Tinea capitis, Tinea barbae and unguium
- 7. T. mentagrophytes morphology • Microconidia – globose but may appear tearshaped – are found primarily in grape like clusters, numerous, spiral nodular bodies – when it is abundant, it will produce granular colonies (Corn meal agar)
- 8. T. mentagrophytes morphology • Macroconidia – thin walled, smooth and cigar shaped, with 4-5 cells septated by parallel cross walls.
- 10. Produces two distinct colonial forms: • the downy variety recovered from patients with tinea pedis • and the granular variety recovered from lesions acquired by contact with animals. • Rose brown on reverse side of colony
- 11. Trichophyton rubrum • Has no specific nutritional requirements. It does not perforate hair in vitro or produce urease. • Ectothrix- hair shaft reveals sheaths of isolated chains of large (5 to 10 μm) spores surrounding the hair shaft • Responsible for Tinea corporis (ringworm), Tinea pedis (Athlete's foot), Tinea cruris (jock itch @groin) & Tinea unguiunum (onychomycosis @ nail)
- 13. T. rubrum macroconidia 3-8 celled cylindrical which is somewhat same size with T. mentagrophytes appear as thin-walled, smooth-walled, multicelled, cigarshaped conidia with three to eight septa.
- 14. T. rubrum microconidia • Clavate or pegshaped, tear shaped along hyphae • uncommon in most of the fluffy strains but are more common in the granular strains and occur as small, I'm invading nail cells
- 15. T. rubrum cultural characteristics • SDA media • is a slow-growing organism that produces a flat or heaped-up colony that is generally white to reddish with a cottony or velvety surface. • reaching maturity within 14 days at 25o to 30oC. •Corn Meal Dextrose Agar •The characteristic cherry-red color is best observed on the reverse side of the colony; however, this is produced only after 3 to 4 weeks of incubation.
- 16. Trichophyton tonsurans • causative agent of Tinea capitis in children in many parts of the world • Causes black dot ringworm (hair breaks off) • Endothrix-hyphae within the hair • A careful search for the embedded stub should be carried out by the physician with the use of a bright light since it did not fluoresce at Wood's Lamp • Anthropophilic (prefers humans to animals) however sources vary on its infectivity.
- 17. Trichophyton tonsurans morphology • MICROCONIDIA – Balloon shaped (cornmeal agar), numerous clavate varying in size (balloon forms and matchstick forms) if old – Chlamydoconidia (intercallary) are abundant in old cultures; swollen and fragmented hyphal cells resembling arthroconidia may be seen.
- 18. Trichophyton tonsurans morphology • MACROCONIDIA – rare T.tonsurans' macroconidia often show an irregular or wavy (undulating/ S-shaped) structure.
- 19. T. tonsurans cultural characteristics • grows poorly on media lacking enrichments (casein agar); however, growth is greatly enhanced by the presence of thiamine or inositol in casein agar. • No red pigment @ CmDA • increase growth in Trichophyton Agar 4 14 days of incubation • Buff to brown, wrinkled and suedelike in appearance. The colony surface shows radial folds and often develops a craterlike depression in the center, with deep fissures. The reverse side of the colony is yellowish to reddish brown.
- 20. Conidia is Absent, only Hyphae seen:
- 21. Trichophyton violaceum • Produces an infection of the scalp and body and is seen primarily in persons living in the Mediterranean region, the Middle and Far East, and Africa. • Hair invasion is of the endothrix type; the typical “black dot” type of tinea capitis is observed clinically
- 22. Trichophyton violaceum infection • Direct microscopic examination of the calcofluor white or potassium hydroxide preparation of the nonfluorescing hairs shows dark, thick hairs filled with masses of arthroconidia arranged in chains.
- 23. T. violaceum Microscopic Characteristics • Microconidia and macroconidia are generally not present; only sterile, distorted hyphae and chlamydoconidia are found. • Young hyphae usually stain well in lactophenol cotton blue, whereas older hyphae stain poorly and show small central fat globules and granules.
- 24. T. violaceum cultural characteristics • very slow growing, beginning as cone-shaped, creamcolored, glabrous colonies then will turn heaped up, verrucous (warty), violet to purple, and waxy in consistency. Colonies may often be described as being “port wine” in color. • The reverse side of the colony is purple or nonpigmented. • The growth of T. violaceum is enhanced on media containing thiamine and by Trichophyton Agar 4.
- 25. Trichophyton shoenleinii • causes a severe type of infection (tinea capitis) called favus, sometimes permanet alopeciacharacterized by the formation of yellowish cup-shaped crusts or scutulae. • Organism causes an endothrix-style growth, but without the arthrocondia. Instead, channels are formed within the hair shaft.
- 26. T. shoenleinii microscopic characteristics • In calcofluor white or potassium hydroxide preparations, bubbles maybe seen since the unfilled tunnels in the hair are filled with fluid • The hyphae tend to become knobby and club-shaped at the terminal ends or possessing Antler hyphae (favic chandelier) • Chlamydoconidia are generally numerous.
- 27. T. shoenleinii cultural characteristics • Is a slowly growing organism (30 days or longer) and produces a white to light gray colony that has a waxy surface. • The reverse side of the colony is usually tan or nonpigmented. • All strains of T. schoenleinii may be grown in a vitamin-free medium and grow equally well at room temperature or at 35° to 37° C. Sabouraud dextrose agar, 25℃, 62 days Potato dextrose agar , 25℃, 27 days.
- 28. Trichophyton verrucosum • causes a variety of lesions in cattle and in humans-The lesions are found chiefly on the beard, neck, wrist, and back of the hands
- 29. T. verrucosum morphology • chlamydoconidia in chains with septa appearing fission flakes and antler hyphae may be the only structures observed • Chlamydoconidia may be abundant at 35° to 37° C.
- 30. T. verrucosum morphology • Microconidia may be produced by some cultures if the medium is enriched with yeast extract or a vitamin • Macroconidia are rarely formed, vary considerably in size and shape, and are referred to as “rat tail” in appearance.
- 31. T. verrucosum cultural characteristics • grows slowly (14 to 30 days), and growth is enhanced at 35° to 37° C and also on media enriched with thiamine and inositol. • Kane and Smitka described a medium for the early detection and identification of T. verrucosum- The ingredients for this medium are 4% casein and 0.5% yeast extract. – The organism is recognized by its early hydrolysis of casein and very slow growth rate. Chains of chlamydoconidia are formed regularly at 37°C. • hence can be differentiated into T. shoenleinii
- 32. T. verrucosum cultural characteristics • Colonies are small, heaped, and folded, occasionally flat and disk-shaped. • Colonies range from gray and waxlike to a bright ochre. • The reverse of the colony is most often nonpigmented but may be yellow.
- 33. Epidermophyton • • • • • Is a common cause of tinea cruris and tinea pedis. This organism is susceptible to cold temperatures E. flocossum only specie never produces microconidia Macroconidia are describe as "Beaver tails", "Snow shoes" and "Paddle shaped"
- 34. E. flocossum morphology • Numerous smooth, thinwalled, club-shaped, multiseptate, which is 24 septa (2 to 4 μm) macro- conidia are seen – is useful in differentiating it from Microsporum species. •Spiral hyphae are rare, and chlamydoconidia are usually numerous.
- 35. E. flocossum cultural characteristics • grows slowly and growth appears as an olive-green to khaki color, with the periphery surrounded by a dull orangebrown color. • Colonies develop a cottony white aerial mycelium that completely overgrows the colony
- 36. Summary Table- w/ conidia Microconidia Macroconidia Colony reverse Special consideration T. mentagrophytes En grappe cigar shaped can have spiral hyphae downy star shaped rose brown Urease + in 2 days T. rubrum sleeve like cigar tear shaped shaped heaped-up that is white to reddish w/ a cottony surface cherry red Urease (-) T. tonsurans ballon shaped rare suedelike appearance; buffbronwn w/ crater yellowish- Intercallary reddish chlamydoco brown nidia Never produce Beaver tails, paddle shaped, snow shoes Olive green-khaki color surrounded by dull orange w/ aerial mycelium Specie Epidermophyton
- 37. Summary Table-only hyphae specie Chlamydoconidia Hyphae Colony Reverse T. violaceum none, instead arthroconidia in chains distorted "port wine" purple or nonpigmented T. shoenleinii numerous knobby & club shaped @ terminal ends appearing Antler white-gray waxy tan or pigmented T. verrucosum in chains; "fission flakes" Antler disk shaped; waxlike that is bright onchre non-pigmented or yellow