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Microsporum fungi.
- 1. Pathogenic Fungi : MICROSPORUM Presented by: Neha kausar Nasim sheikh
- 2. CONTENT • Introduction • Morphological characteristics • Pathogenesis • Laboratory diagnosis • Treatment
- 3. INTRODUCTION • Microsporum is the genus of fungi comes under Dermatophytes group • Dermatophytes- it is a group of three types of fungus i.e. Microsporum, Trichophyton and Epidermophyton that causes skin diseases in Humans and Animals. • Microsporum fungi infects only keratinized tissue like skin, hair and Nails. • They are restricted to non-viable skin because they are unable to grow at 37 degree Celsius. • Enzymes which helps the fungi are Proteases, Elastase, Keratinases. These are degradative enzymes which degrade keratinized tissue and serves as nutrients for the fungi. • Natural habitat of some microsporum spp. Is soil(geophilic) others primarily affect animals(zoophilic) or human(Anthropophilic). • The infection caused by Microsporum are known as ringworm or tinea , Though infections are not caused by worms but it appear as snake-like on skin, hence named ringworm infection.
- 4. MORPHOLOGICAL CHARECTERISTICS • Microsporum can be identified by their colonial appearance and microscopic morphology after growth for 2weeks at 25 degree Celsius on Sabouraud’s dextrose agar. • Microsporum species tend to produce distinctive multicellular machroconidia with echinulate walls. • Microsporum forms both Macroconidia and Microconidia on short conidiosphores(hyphae). MACROCONIDIA MICROCONIDIA Large asexual reproductive structure. Small asexual reproductive structure. Hyaline, Multi sepate(2- 15) Hyaline, single septate Spindal shaped Club shaped Rough and Thick walled Smooth and Thin walled 8 to 15 X 40 to 150 µ m 2 to 3 µ m
- 5. Microsporum canis • Colonies :- white cottony surface and deep yellow color on reverse, Thick walled. • On the rice grains, a deep yellow pigment is produced by M.canis which helps to differentiate it from M.audouinii • Macroconidia are abundant. Thick walled with many septa up to 15 . Macroconidia are often hooked or curved at ends. • Microconidia are small and club-shaped. • In-vitro hair perforation test :- Positive • M.canis causes tinea capitis and tinea corporis. Tinea barbae, tinea mannum.
- 6. Microsporum audouinii • Colonies :- dense fur like mat having radiating edges, Grayish white to salmon pink colored colonies. • Pectinate hyphae and rare macroconidia and microconidia. • Anthropophilic. • Hair and skin infected with M.auduinii gives fluorescence under wood’s UV light. • In-vitro hair perforation test :- Negative • It causes tinea capitis and tinea corporis
- 7. Microsporum gypseum • Colonies :- forms a tan, powdery colony, reverse colony often appear ragged around edges. • Macroconidia usually have 4-6 septa. • Microconidia are smaller than M.canis • Geophilic as well as Zoophilic (fur of rodents) • It causes Tinea capitis & Tinea corporis
- 8. Microsporum ferrugineum • Colonies:- slow growing , flat, glabrous, wrinkled, leathery to downy. • Pale yellow colonies on Lowenstein-Jensen medium differentiate it from others. • Septate hyphae usually deformed and no Macroconidia, Microconidia • In-vitro hair Perforation test :- Negative • Causes tinea capitis.
- 9. PATHOGENESIS Tinea Capitis:- Ringworm of scalp and hair • Hyphal invasion of skin of scalps • Spread to the keratinized wall of hair follicle • Hypha grow downward on nonliving portion of hair • As the hair grows upward the hyphae produce chain of spores that forms a sheath around hair shaft • The infection produce dull gray circular itchy patches.Tinea Corporis:- Ringworm infection of the body(smooth skin) • Fungal metabolites, Enzymes, Antigens diffuse through the viable layer of epidermis • Vesicle formation • Lesion expand centrifugally and active hyphal growth at periphery.
- 10. Tinea Manuum:- Ringworm of the hands. • Shows red itchy rash, burning, cracking and scaling • May be transmitted sexually or via scratching and touching. • It typically starts as a small patch than gradually becomes larger. Tinea Barbae:- Ringworm of the beard and moustache. • Same as tinea capitis. • Infection occur as a follicular inflammation. • Mostly caused by Trichophyton rarely caused by Microsporum spp.
- 11. SPECIES NATURAL RESERVOIR RINGWORM INFECTION Microsporum audouinii Anthropophilic Tinea corporis & Tinea capitis Microsporum canis Zoophilic (Cats and dogs) Tinea corporis,Tinea capitis,Tinea mannum, Tinea barbae Microsporum ferrugineum Anthropophilic Tinea capitis Microsporum gypseum Geophilic (also isolated from fur of rodents) Tinea corporis & Tinea capitis
- 12. 1. Nail clipping, skin scrapings, hair placed in a slide than 10- 20%KOH is added with Lactophenol blue stain and examine the sample with a microscope to determine presence of hyphae. 2. Wood's lamp examination (ultraviolet light) may be used to diagnose microsporum spp. that fluoresce. LABORATORY DIAGNOSIS Spores of microsporum spp. Impart greenish to silvery fluorescence when examined under Wood’s lamp.
- 13. M. canis :- Positive M. auduinii :- Negative 3. Fungal culture medium can be used for positive identification of the species i.e. Sabouraud’s dextrose Agar(SDA). 4. In-vitro hair perforation Test : Placing an organism in a petri-dish with water, yeast extract and hair sample. TREATMENT General Antifungal medications can be used to treat microsporum (ringworm) infections, • Topical medications :- clotrimazole, miconazole, econazole and terbinafine. • Oral medications :- Ketaconazole, griseofulvin, terbinafine, and itraconazole.
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