Trichophyton mentagrophytes (1)

My name is Shelly Meier and I am a graduate student at Western Illinois University. As a Master’s student I have enjoyed taking various classes, including Mycology and Medical Mycology. These classes sparked my interest in fungi and I have really enjoyed learning about all of the different infections and illnesses that can be caused by fungi that are present all around us. The Trichophyton fungi are rather common and hopefully as interesting to you as they are to me.

 

Taxonomy (3)

 

Kingdom: Fungi

Phylum: Ascomycota

Class: Eurotiomycetes

Order: Onygenales

Family: Arthrodermataceae

Background

Trichophyton fungi are part of the Ascomycota phylum and can be characterized by the presence of microconidia and macroconidida (2) (See pictures of macro and microconidia). Trichophyton causes a wide variety of hair, skin, and nail infections. This fungus can be found in the soil as well as on humans and animals (1). It can be considered a cosmopolitan fungus, but some species can only be found in certain areas(1).

Macroconidia of Trichophyton tonsurans (4)    

Microconidia of Trichophyton rubrum (4)

Trichophyton is a keratinophilic, filamentous fungus and is one of the main causes of dermatophytosis in humans and animals. Dermatophytosis is simply an infection caused by a dermatophyte, which is a fungus that survives by using the keratin in substrates as its food source.                        

The following chart is a list of some common species and their habitats, as well as how often they cause an infection

Species	Natural habitat	Incidence
Trichophyton rubrum	Humans	Very Common
Trichophyton interdigitale	Humans	Very Common
Trichophyton tonsurans	Humans	Common
Trichophyton violaceum	Humans	Less Common
Trichophyton concentricum	Humans	Rare*
Trichophyton schoenleinii	Humans	Rare*
Trichophyton soudanense	Humans	Rare*
Trichophyton mentagrophytes	Mice, rodents	Common
Trichophyton equinum	Horses	Rare
Trichophyton erinacei	Hedgehogs	Rare*
Trichophyton verrucosum	Cattle	Rare

The cultures of Trichophyton spp. can have a waxy, to cottony texture and be white to bright yellowish beige or red violet on the front, and pale yellowish, brown or reddish brown on the reverse side (1).

Trichophyton tonsurans culture (2)

Front side of culture Trichophyton tonsurans (2).

Clinical Cases

Trichophyton mentagrophytes var. erinacei transmitted from a hedgehog to a human.

A 21 year old female had a scaly, red, itchy plaque on the tip of her nose. She had been bitten by her pet hedgehog 2 weeks prior to the first appearance of symptoms. The plaque was determined to be Tinea faciei, caused by Trichophyton mentagrophytes var. erinacei. The young woman was treated with topical and systemic terbinafine 250mg/day for eight weeks (5). 

For more information and the entire case study visit: http://web.ebscohost.com/ehost/detail?vid=3&hid=14&sid=874459a6-0b6f-495a-a884-6f411b90d0af%40sessionmgr4&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=aph&AN=71839143

Invasive cutaneous Trichophyton schoenleinii infection in an immunosuppressed patient

A 65 year old man experiences asymptomatic red papules on his upper and lower limbs as well as his forehead. The man had undergone a kidney transplant 3 months prior to the papules appearing. The papules were swabbed and the culture grew what turned out to be Trichophyton schoenleinii. The man was treated with intraconazoles and the papules soon went away (6). 

For more information and the entire case study visit: http://web.ebscohost.com/ehost/detail?vid=5&hid=14&sid=874459a6-0b6f-495a-a884-6f411b90d0af%40sessionmgr4&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=aph&AN=65804040

The following pictures are of some infections caused by Trichophyton species. Some may not look bad, but if left untreated, they can get worse and sometimes spread throughout the body.

Tinea capitis due to Trichophyton tonsurans (8) 

"Clinical presentations of some frequently observed fungal infections: (a) Tinea capitis due to Trichophyton tonsurans; (b) onychomycosis due to Trichophyton rubrum; (c) chronic oral candidiasis; (d) chromoblastomycosis; (e) histopathological appearance of an aspergilloma. (f) Cutaneous lesions in a patient with disseminate candidiasis"(9).

Prevention and Treatment

While a Trichopyton infection can be treated, it is much easier and healthier to just prevent the fungus from entering your body. Some prevention methods include: 

• Daily bathing 
• Making sure to dry off completely when done showering or swimming 
• Be very cautious in public areas and always wear footwear
• Don't share items like brushes, combs, and nail clippers 
• Good hand washing- frequently
• Any you should always practice all around good hygiene 

This fungus can be treated rather easily, depending on the infection. Most cases of cutaneous infections topical treatments, such as intraconazole, or any azole can be used for treatment. If the infection is very severe Amphotericin B may be administered. 

Useful Websites

http://www.mycology.adelaide.edu.au/

http://www.doctorfungus.org

http://www.cdc.gov/fungal/dermatophytes/

References
1. http://www.doctorfungus.org/thefungi/trichophyton.php
2. http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Dermatophytes/Trichophyton/
3. http://www.speciesfungorum.org/names/Names.asp
4. http://labmed.ucsf.edu/education/residency/fung_morph/fungal_site/dermatpage.html
5. Concha M, Nicklas C, Fich F, et al. The first case of tinea faciei caused by Trichophyton mentagrophytes var. erinacei isolated in Chile.         International Journal Of Dermatology . March 2012;51(3):283-285.
6. Dan P, Rawi R, Hanna S, Reuven B. Invasive cutaneous Trichophyton shoenleinii infection in an immunosuppressed patient.         International Journal Of Dermatology . October 2011;50(10):1266-1269. 7. Larone, Davise Honig, (2002). Medically important fungi: a guide to identification. ASM Press. 8.http://www.google.com/imgres?hl=en&sa=X&biw=1024&bih=629&tbm=isch&prmd=imvns&tbnid=Z4Mk0zg1UCUqQM:&imgrefurl= http://reference.medscape.com/features/slideshow/tinea&docid=2zwW4ZbFt67ttM&imgurl=http://img.medscape.com/pi/features/ slideshow-slide/tinea/fig4.jpg&w=522&h=355&ei=K9KiT6G_HuLZ0QG_0IXVDA&zoom=1&iact=hc&vpx=109&vpy=161&dur=301&hovh=133
9.Jain, Akansha, Shubham Jain, and Swati Rawat (2010). Emerging Fungal Infections among Children:  A Review on Its Clinical Manifestations, Diagnosis, and Prevention. Journal of Pharmacy and Bioallied Sciences 2.4: 314.