Polyphasic Discrimination of Trichophyton tonsurans and T. equinum from Humans and Horses
The anthropophilic dermatophyte Trichophyton tonsurans and its zoophilic counterpart T. equinum are phylogenetically closely related. The barcoding marker rDNA internal transcribed spacer (ITS) shows limited variation between these two species. In the current study, we combined molecular approaches with phenotypic data to determine the species boundaries between T. tonsurans (n = 52) and T. equinum (n = 15) strains originating from humans (n = 40), horses (n = 26), and a mouse (n = 1). Culture characteristics and physiology on Trichophyton agar media 1 and 5 were evaluated. Multi-locus sequencing involving ITS, partial large rDNA subunit (LSU), β-tubulin (TUB), 60S ribosomal protein (RPB), and translation elongation factor-3 (TEF3) genes, and the mating-type (MAT) locus was performed. Amplified fragment length polymorphism data were added. None of the test results showed complete mutual correspondence. With the exception of strains from New Zealand, strains of equine origin required niacin for growth, whereas most strains from human origin did not show this dependence. It is concluded that T. tonsurans and T. equinum incompletely diverged from a common lineage relatively recently. MAT1-1 and MAT1-2 are the main distinguishing genes between the two species.
KeywordsAmplified fragment length polymorphism Multi-locus sequencing Biodiversity Mating type Physiology Trichophyton
HK was supported by a Grant from the Federation of European Microbiological Societies (FEMS-RG-2016-0067). The funders had no influence on the study design; on the collection, analysis, and interpretation of data; on the preparation of the manuscript; or the decision to publish.
Conflict of interest
The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of this paper.
This article does not contain any studies with human participants or animals performed by any of the authors.
- 1.Gruby D. Mémoire sur une végétation qui constitue la vraie teigne. C R Acad Sci. 1841;13:72–5.Google Scholar
- 3.Georg LK, Camp LB. Routine nutritional tests for the identification of dermatophytes. J Bacteriol. 1957;74(2):113–21.Google Scholar
- 12.Gedoelst L. Les champignons parasites de l’homme et des animaux domestiques. Lierre & Brussels: H. Lamertin, 1902:88–9.Google Scholar
- 15.Stros K, Krivanec K, Komárek J, Malinský B. Occurrence of an outbreak of horse dermatophytosis caused by the fungus Trichophyton equinum. Vet Med (Praha). 1978;23(3):175–84.Google Scholar
- 22.Gerrits van den Ende AHG, de Hoog GS. Variability and molecular diagnostics of the neurotropic species Cladophialophora bantiana. Stud Mycol. 1999;43:151–62.Google Scholar
- 27.Kathuria S, Sharma C, Singh PK, et al. Molecular epidemiology and in vitro antifungal susceptibility of Aspergillus terreus species complex isolates in Delhi, India: evidence of genetic diversity by amplified fragment length polymorphism and microsatellite typing. PLoS ONE. 2015;10(3):e0118997.CrossRefGoogle Scholar
- 32.Rebell G, Taplin D. Dermatophytes: their recognition and identification. Coral Gables, FL; University of Miami Press: 1979. pp. 45–6;52–3.Google Scholar
- 38.Dukik K, Freeke J, Jamalian A, et al. Ultra-High-Resolution Mass Spectrometry for identification of closely related dermatophytes with different clinical predilections. J Clin Microbiol. 2018;56(7):pii:e00102–18.Google Scholar
- 41.Summerbell R. Trichophyton, Microsporum, Epidermophyton, and agents of superficial mycoses. In: Versalovic J, Carroll K, Funke G, Jorgensen J, Landry M, Warnock D, editors. Manual of Clinical Microbiology. 10th ed. Washington DC: ASM Press; 2011. p. 1919–42.Google Scholar