Trichophyton is the name for a genus of filamentous fungi. This can cause diseases of the skin and hair.
What is trichophyton?
Various dermatophytes are grouped under the name Trichophyton. They are also part of the Arthrodermataceae family. Trichophytes form a genus of filamentous fungi and belong to the Fungi imperfecti (imperfect fungi). These are representatives of higher fungi, such as yoke fungi, stand fungi and tube fungi. Reproduction of these fungal species is purely vegetative or by spores that are formed asexually. In addition, the trichophytes are responsible for the development of trichophytia. In this case, fungal diseases occur on the skin and hair of humans and animals. Not infrequently, a zoonosis between humans and animals takes place.
Occurrence, distribution and characteristics
Trichophyton species are found in the soil. However, they can also colonize the bodies of humans and animals. In addition to zoophilic trichophytes, anthropophilic as well as geophilic species also exist. While some species are found all over the world, others thrive only in certain regions. One of these is Trichophyton concentricum. This fungus lives exclusively in Central America, the Pacific Islands and Southeast Asia. Together with the trichophytes, two other genera are capable of causing dermatophytes. These are the epidermophytes and the Microsporum. All three species belong to the filamentous fungi and obtain the energy for their growth from the decomposition of carbohydrates and keratin, which is carried out by the enzyme keratinase. The three fungal species can be differentiated by morphological differences. There are 26 species of Trichophyton known to science. These include above all Trichophyton mentagrophytes, which affects cats, dogs and rodents as well as humans, Trichophyton rubrum, which can affect horses and cattle as well as humans, and Trichophyton verrucosum. This species of Trichophyton is restricted to cattle and horses. The most common Trichophyton species also include Trichophyton tonsurans, Trichophyton schoenleinii, and Trichophyton violaceum. The colonies of the trichophytes have a cotton wool-like and velvety surface with a white-brownish coloration. In their taplin agar, there is a discoloration from orange-yellow to red. With the aid of a microscope, rounded club-shaped macroconidia can be seen on the fungi. However, not every Trichophyton species is equipped with these macroconidia. If they are present, they have one to twelve septa that have a thin smooth cell wall. They are usually solitary or in clusters. They may be cylindrical, club-spindle shaped, or elongatedly pointed. The size of the macroconidia varies greatly. Microconidia are present more frequently than macroconidia. They are stalked or sessile and have the shape of a club or pear. They arise on the hyphal sides either in racemose clusters or singly. Some can sporulate only on suitable media. The main nutritional component of trichophytes is keratin, which is found in the hair and nails of humans and animals. Trichophytes live parasitically, which is why they are classified as dermatophytes. While Trichophyton rubrum and Trichophyton tonsurans settle parasitically on human hair, nails and skin, Trichophyton verrucosum and Trichophyton equinum thrive on the skin and fur of mammals. Rather rarely parasitic are trichophytes such as Trichophyton ajelloi, whose habitat is the soil or fallen fur. Transmission of Trichophyton fungi can occur directly from person to person. In addition, infection with the fungus is also possible through contact with infected animals or contaminated soil. In this case, the skin, hair, and nails of humans are infected.
Diseases and symptoms
Trichophytes are the main cause of fungal infections of hair, skin, and nails. The virulence factors of the fungal species are formed by several enzymes such as elastase and proteinase. In addition to infection by other people or animals, the affected person can also contract the fungus from objects such as carpets or clothing, as well as dust or moisture in swimming pools or showers. The genus Trichophyton has the property to cause dermatomycoses. This primarily includes skin mycosis (tinea coporis). The affected persons suffer from scaly reddish efflorescences.These start in the center of the body and then spread further to the outer areas. The main causative agent of tinea corporis is Trichophyton mentagrophytes. Also caused by trichophytes is nail mycosis (tinea unguium). Besides Trichophyton mentagrophytes, Trichophyton rubrum is also one of the most frequent triggers. Furthermore, hair mycosis (tinea capitis) can occur, for which Trichophyton tonsurans is mostly responsible. Hair mycosis is noticeable by brittle hair. A subtype of hair mycosis is tinea barbae, in which the facial beard hairs are affected by trichophytes. Trichophyton mentagrophytes and Trichophyton rubrum are responsible for this. If a fungal infection by trichophytes occurs due to transmission by an animal, the disease usually takes a more severe course than by infection from person to person. A possible complication is a bacterial superinfection. In order to make a diagnosis and detect the pathogen in question, the examining physician removes a few scales from the edge of the damaged skin regions. Likewise, parts of nails or hairs of the patient can serve as examination material. The trichophytes are detected by preparing a fungal culture and microscopic examination. Trichophyton can be effectively controlled by the use of antifungal agents such as ketoconazole, itraconazole, fluconazole, amorolfine, naftifine, terbinafine, or clotrimazole.
