From Big Medical Encyclopedia

DERMATOMITSETA (Dermatomyces, singular; grech, derma, dermat[os] skin + mykes, myket[os] mushroom; synonym dermatophytes) — extensive group of the pathogenic fungi which are activators of dermatomycoses of animals and the person. Activators of dermatomycoses (see. Fungus diseases of skin) are Microsporums, trikhofitona and epidermofitona.

Affect skin and its appendages; are characterized expressed keratinofilnostyo, morfobiol. dimorphism (distinction of fabric and cultural forms) and pathogenicity of fabric forms.

The general morfol, D.'s signs is the septirovanny branchy mycelium to dia. 1 — 10 microns. At some D. the mycelium comes to an end with thin short moustaches, curls and spirals or short branchings, at others — on the ends of a mycelium club-shaped swellings to dia are located. 10 — 15 microns.

Sporogenesis at D. is carried out by the round or pear-shaped microconidiums (aleyriya) which are located odinochno, couples or clusters on each side or on the ends of a mycelium; the sizes vary them from 2 —-3 to 5 — 7 microns. Macroconidiums — multicellular, spindle-shaped, the large size, from 5 — 7 to 40 long — 50 microns, 3 — 15 microns wide; hl meet. obr. in cultures of Microsporums.

Many D. roundish intercalary (intermediate) and trailer chlamydospores are inherent to dia. 15 — 20 microns and the rectangular or slightly extended artrospor (3х6 microns). To Sporonosheniye D. clearly it is expressed in mature cultures; chlamydospores meet in old colonies more often.

Morphology of the fabric forms D. which are found in patol, the material taken from patients from the centers of defeat, quite uniform. In D.'s scales meet in the form of the septirovanny mycelium which is breaking up to rectangular or roundish cells.

In the hair affected with D. there is a large number round a dispute, the hair (endothrix) which are located entirely filling and out of it (ectoendothrix, neoendothrix), and for some fungi — only outside of a hair (ectothrix). The sizes D.'s dispute in a hair various; smaller to dia. 2 — 3 microns are inherent to Microsporums. Trikhofitona by the sizes a dispute in a hair are subdivided into large and sporous (megaspores) with disputes to dia. 4 — 6 microns and smaller to dia. 2 — 3,5 microns (microides).

For implementation in D.'s hair form the special bodies of a penetration (implementation) of various form and the size which are easily revealed at crops on sterile horse and children's hair in Petri dishes at t ° 35 °.

— aerobes, well grow on dense and liquid mediums with carbohydrates (Saburo's circle, a must, synthetic environments). D.'s cultures reach a maturity to 15 — to the 20th day of cultivation at t ° 28 — 30 °. On intensity of growth some D. (e.g., Microsporum canis) are subdivided into two types: evgonichesky, quickly and magnificently growing, with plentiful sporogenesis, both d and sgon and chesky, characterized by the slowed-down growth, scanty fructification and atypical colonies.

On the nature of growth on agar mediums (Saburo's circle, a must) distinguish leathery, fluffy, velvety, mealy and wax-like and wrinkled types of colonies of cultures of.

Leathery colonies — smooth, sometimes brilliant, in the center small - looped or folded, closely soldered to substrate. They consist of a chetkoobrazny mycelium, chains from roundish and many-sided a dispute; in them quite large intercalary and trailer chlamydospores meet. Leathery cultures are inherent to Trichophyton violaceum, Tr. glabrum, Tr. verrucosum.

Fluffy — quickly growing cultures of whitish color with a magnificent air mycelium; surface of colonies equal. They consist from septirovanny, at some D. bambukovidny, a mycelium with abundance of large spindle-shaped multicellular (6 — 12) macroconidiums; chlamydospores and microconidiums meet seldom. Fluffy cultures are inherent to Microsporum canis, M. to audouinii, Tr. niveum.

Velvety colonies of culture have a dense short air mycelium; develop quickly enough, are densely soldered to a surface of the environment, offsprings in depth of substrate sometimes have. A surface of cultures of an ischerchen of various depth grooves and folds with cracks at tops. Under a microscope in them the branchy mycelium, pear-shaped microconidiums, sometimes short spindle-shaped macroconidiums are visible. Velvety colonies are inherent to various Tr options. tonsurans, var. crateri .forme, cerebriforme, exsiccatum, Tr. quinckeanum.

The mealy type of colonies is characterized by rapid growth, a plentiful mealy plaque is white about vatozheltovaty color, entirely or the star-shaped centers covering nutritious substrate; growing of a mycelium on Wednesday is changeable. In mealy cultures roundish microconidiums, short fragments of a mycelium prevail; in young cultures curls and spirals, spindle-shaped 4 — 6 - cellular macroconidiums meet. Mealy cultures are inherent to various representatives from the Tr group. mentagrophytes, M. gypseum.

Wax-like and wrinkled cultures of yellowish-whitish color, a kroshkovaty consistence, sometimes with offsprings in depth or at the edges of colony; the centers barkhatisto y mealiness meet changeably. Under a microscope short fragments of the granular mycelium sometimes branching in the form of candelabrums, numerous club-shaped trailer and roundish iiterkalyarny chlamydospores, and also large (15 — 25 microns) blunt-pointed rudiments of macroconidiums without partitions are visible. Microconidiums meet only in velvety and mealy sectors of colonies. Wax-like and wrinkled cultures are characteristic of Tr. schoenleinii, Tr. ferrugineum.

Almost all D., especially in the conditions of long-term museum storage, are exposed to the pleomorfichesky degeneration which is followed by permanent loss of a sporonosheniye, decrease in karbolitichesky activity and pathogenicity. Such cultures consist of the thin, deprived a dispute («sterile») mycelium. Recovery of a typical type of cultures and a characteristic sporonosheniye is reached with great difficulty in passages on agar mediums with aqueous extracts (1: 10) from the hothouse garden earth.

Biochemical, D.'s activity is quite various also a labilna concerning carbohydrates. Keratolytic activity is inherent to almost all D., intensity a cut is most expressed at geofilny D. and, in particular, M. have gypseum, Keratinomyces ajelloi.

Antigenic properties D. do not differ in high specificity; group antigens, the general various D. come to light that is fair also for allergens. More accurate distinctions are found in a precipitation test and RSK, results of allergy skin tests are less specific.

D.'s identification serol, methods and differentiation on biochemical, activities need further researches.

In the attitude towards parasitic activity of D. are subdivided on anthropophilous, striking almost only the person (Tr. violaceum, Tr. tonsurans, Tr. schoenleinii, Tr. rubrum), zoophilous, or zooanthropophilous, striking preferential animal, and also the person (M. canis — cats, dogs and the person; Tr. mentagrophytes — rats, mice, sheep, is much more rare than the person; Tr. verrucosum — cattle and the person), and geofilny, saprophytes of the soil, sometimes defiant diseases at animal (rodents) and is even more rare than the person (M. of gypseum).

In the soil the separate group of keratinofilny fungi comes to light. The most frequent representative of this group D. — Keratinomyces ajelloi; its pathogenic activity is studied insufficiently.

Vanbreyzegem (R. Vanbreuseghem, 1952) showed a possibility of cultivation of D. in the soil and on soil substrates, especially at addition of keratinosoderzhashchy substances.

The soil can be a habital of many D.; their development depends on a complex of factors there: physical. - chemical structure of the soil, a degree of wetness and reaction (pH) of the environment, a temperature schedule of e of insolation, and also the nature of processing of the soil. Value of the soil in epidemiology of dermatomycoses finally is not found out.

In soils of various geographical zones of the USSR Tr are found. terrestre, Tr. ajelloi, Tr. mentagropiiytes, Tr. georgiae, Tr. simii; M. cookei, M. gypseum; Keratinomyces ajelloi, and also perfect forms — Tr. mentagrophytes, Tr. simii, Tr. georgiae; Keratinomyces ajelloi.

Perfect forms of D. possess fruit bodies (kleystotetion) which contain bags with disputes, testimonial of their belonging to gimnoaskovy. For cultivation of perfect forms and geofilny D.' identification in the soil soil extracts of 20 g of the soil are used, 100 ml of water), to the Crimea add peptone or a keratin, grains of oats, barley, flax or corn.

See also Fungi parasitic .

Bibliography: Cat's P. N. Dermatomycoses (person and animals), L., 1967, bibliogr.; Fejer E., etc. A medical mycology and fungus diseases, the lane with Wenger., M., 1966, bibliogr.; And j e 1-1 about L. a. G h e n g S. L. The perfect state of trichophyton mentagrophytes, Sabourau-dia, y. 5, p. 230, 1967; De V r o e y G h. Contribution a l’etude des dermatophytes et d’autres gymnoascacees, Ann. Soc. beige Med. trop., t. 50, p. 1, 1970, bibliogr.; TakashioM. Etude des pher.o-menes de reproduction lies au vieillissement et au rajeunissement des cultures de champignons, ibid., t. 53, p. 427, 1973, bibliogr.

P.N. Kashkin.