[Tinea caused by Trichophyton equinum].

The study reports the first case in Germany of a human infection by the Trichophyton equinum fungus, inherited from a pony, noting that human susceptibility to this infection may largely involve predisposing factors and close contact with infected horses.

Identification of Trichophyton equinum

• This particular fungus was identified in a 12-year old girl who got infected from a pony.
• Trichophyton equinum was recognized by its individual characteristics, such as its morphology, its dependency on nicotinic acid, and its ability to perforate hair and produce enzymes.
• Unique to this study, the researchers observed the development of white pleomorphic tufts on the surface of thalli grown on a potato-dextrose agar – a common nutrient medium used in laboratories.

The Tinea Infection

• The girl’s tinea, a skin infection caused by the fungus, was non-inflammatory and responded quickly to topical treatment.
• In contrast, the pony from which the girl got infected suffered from intense inflammatory lesions for several months.

The Pathogenic Potential of Trichophyton equinum

• The study authors measured enzyme patterns for Trichophyton equinum in cultures supplemented with different nutrients.
• They found these patterns to be similar to those of other more pathogenic species of dermatophytes (a group of fungi that cause skin diseases) for humans.
• Contrary to what might have been expected, the rarity of human infections with Trichophyton equinum doesn’t seem to be because of a lack of enzymes.

Predisposing Factors for Infection

• The researchers propose that certain predisposing factors in the host, combined with close contact to infected horses, might make one more susceptible to this particular infection.
• However, they stipulate that treatment of infected humans does not pose a major issue, as the human infection responds promptly to treatment.