Trichophyton mentagrophytes - Pathogenesis, Host Immunity, Risk factors, Epidemiology, Reservoir, Transmission, Treatment
Pathogenesis of Trichophyton mentagrophytes
Trichophyton mentagrophytes infection is typically restricted to the upper layers of the epidermis but in some cases, deeper infections may occur. Trichophyton mentagrophytes grow down into the stratum corneum where it is able to invade keratin.
Dermatophytes such as Trichophyton mentagrophytes, grow within the dead, keratinized tissue of its human host. Trichophyton mentagrophytes are able to produce keratinolytic protease enzyme (keratinase) in vivo which aids the fungi to penetrate into living cells and use keratin as a source of nutrition. This results in wedge-shaped perforation on the infected hair.
In humans, males are more often infected than females.
Host Immunity against Trichophyton mentagrophytes
Trichophyton mentagrophytes infection does not elicit strong inflammatory responses. The fungi are able to suppress cellular immune responses including lymphocytes (particularly T cells).
A pathologically important fungal cell wall component is mannan, which also suppresses host immune responses. However, the exact mechanism remains undiscovered.
The fungi have been associated with the induction of an id reaction in which acute dermatitis develops for days or weeks at skin locations that are distant from the infectious site or initial inflammatory area.
Risk factors of Trichophyton mentagrophytes
Risk factors of Trichophyton mentagrophytes include diabetes, humid environment, high blood pressure, weak immune system, excessive sweating, cracks in feet, and recurrent hand trauma.
The profession and gender of an individual also determine fungal infection. Farmworkers, machine operators, mechanics, people who work with chemicals, electricity workers, gas workers, and pet owners have a higher incidence of infection while on the basis of gender, more males are infected than females.
Epidemiology of Trichophyton mentagrophytes
Trichophyton mentagrophytes are zoophilic and worldwide in distribution.
The profession and gender of an individual also determine fungal infection. Farmworkers, machine operators, mechanics, people who work with chemicals, electricity workers, gas workers, and pet owners have a higher incidence of infection while on the basis of gender, more males are infected than females.
Reservoir, Source of Trichophyton mentagrophytes
Humans and animals are natural reservoirs for Trichophyton mentagrophytes, which is Zoophilic. Companion animals such as cats, dogs, rabbits, and rodents (including guinea pigs) are the main source, natural reservoirs of Trichophyton mentagrophytes.
Human-to-human transmission occurs by some genetic variants e.g. Type VII and Type VIII. Distinct geographical ranges have a particular genetic variant.
Transmission of Trichophyton mentagrophytes
Infected companion animals transmit Trichophyton mentagrophytes to humans due to close proximity living.
Trichophyton mentagrophytes can be transmitted via contact with infected skin or hairs. Fomites such as combs, towels, brushes, barber shop clippers, or scissors are responsible for the transmission of Trichophyton mentagrophytes from one person to another.
Use of unhygienic common showers, dressing rooms, and swimming pools where desquamated skin is a source of Trichophyton mentagrophytes infection is responsible for the transmission of athlete’s foot.
Treatment of Trichophyton mentagrophytes
Miconazole, Clotrimazole, and Tolnaffate - creams are used for the treatment of mild Trichophyton mentagrophytes infection.
Griseofulvin – oral administration in severe infections for a severe skin infection (4 to 6 weeks) and severe nail infection (1 year).
Prevention, Control of Trichophyton mentagrophytes
Trichophyton mentagrophytes can be prevented/controlled by following steps:
avoid moisture build-up in vulnerable areas such as the groin
avoid tight clothing
lose weight if the infected individual is obese
not sharing towels or other fomites
proper cleaning/sanitizing of public showers, bathrooms, dressing rooms, and swimming pools
proper and complete treatment of infected individuals including pets