Trichophyton mentagrophytes is a species in the fungal genusTrichophyton,[1] and the type species of theTrichophyton mentagrophytes complex[2]. It is one of three common fungi which causeringworm incompanion animals. It is also the second-most commonly isolated fungus causingtinea infections in humans, and the most common or one of the most common fungi that causezoonotic skin disease.Trichophyton mentagrophytes is frequently isolated from dogs, cats, rabbits,guinea pigs and other rodents,[3][4][5] though at least some genetic variants possess the potential ofhuman-to-human transmission, e.g. Type VII[6] and Type VIII.[7] As of 2024 it is an emergingSTD inmen who have sex with men and insex workers of all genders.[8]
Along with closely relatedT. interdigitale, the species has been traditionally treated as a part ofpolyphyletic assemblage, named "T. mentagrophytes sensu lato".[9][10] From 1999 to 2017 the two species have been collectively referred to asT. interdigitale, while the name "T. mentagrophytes" has been used for currentT. quinckeanum.[1][11][12]Trichophyton interdigitale seems to be strictlyanthropophilic,[13][10] and is associated with foot and nail infections.[14]
Trichophyton mentagrophytes is capable ofmating.[15] This species is also able to undergomeiosis.[16] Thehaploidchromosome complement ofT. mentagrophytes is four. The fusion of haploid nuclei (karyogamy) preceding meiosis occurs in thepenultimate cell of a typicalcrozier, an anatomical feature of the sexual phase of many fungi in the Division Ascomycota.
Trichophyton mentagrophytes is one of three common fungi which causeringworm incompanion animals and frequently isolated from dogs, cats, rabbits,guinea pigs and other rodents.[3][4][5]
It is the most common or one of the most common fungi that causezoonotic skin disease (i.e., transmission ofmycotic skin disease from species to species).[3][4][5]
While it is considered azoophilic species, it is also the second-most commonly isolated fungus causingtinea infections in humans, and at least some genetic variants possess the potential of human-to-human transmission, e.g. Type VII[6] and Type VIII.[7]
Since 2002 cases were reported in Nigerian sex workers, in 2021 inmen who have sex with men in France and as of 2024 in New York City.[17]
Out of all species considered to be a part of theTrichophyton mentagrophytes complex,T. mentagrophytes causes the most severe form of symptoms in humans, including pustules, abscesses and ulceration, and induces a stronginflammatory response in the infected tissue.[18] It causes infections mostly on the trunk, legs and arms (tinea corporis) or on the scalp (tinea capitis), where it mainly targets thekeratinocytes of theepidermis.
T. mentagrophytes induces robustcell death in keratinocytes, more so than the other species in the complex.[18] It causes these effects through different components: necrosis mainly through itshyphae, and apoptosis through its supernatant. The apoptotic effect of the supernatant is attributed toSN-38, a compound best known as an active metabolite ofirinotecan used as a cancer medicine.[18][19]
Particular genetic variants of the fungus have distinct geographic ranges.[14]
For studies on theepidemiology ofT. mentagrophytes, two molecularstrain typing techniques are available. The first one is based upon amplification of nontranscribed spacer ofribosomal DNA,[20] and the second one involves a comparison ofinternal transcribed spacer sequences within defined boundaries.[14]
InT. mentagrophytes, antifungal drug resistance is mainly associated with Type VIII isolates. Drug-resistantT. mentagrophytes strains have been found in many places acrossAsia andEurope.India is the most affected country, with the rate of microbiological resistance toterbinafine estimated at 11.4%.[21] There are also reports on terbinafine-resistant Type II isolates fromJapan andDenmark.[citation needed]
^abcCafarchia C, Weigl S, Figueredo LA, Otranto D (2012). "Molecular identification and phylogenesis of dermatophytes isolated from rabbit farms and rabbit farm workers".Veterinary Microbiology.154 (3–4):395–402.doi:10.1016/j.vetmic.2011.07.021.PMID21840652.
^abcMesquita JR, Vasconcelos-Nóbrega C, Oliveira J, et al. (2016). "Epizootic and epidemic dermatophytose outbreaks caused byTrichophyton mentagrophytes from rabbits in Portugal, 2015".Mycoses.59 (10):668–673.doi:10.1111/myc.12513.hdl:10400.19/3518.PMID27292309.S2CID206200544.
^abLarionov MD, Chilina GA, Bogdanova TV, Pchelin IM (2017). "Rare clinical case of tinea corporis and tinea cruris due toTrichophyton mentagrophytes of exotic genotype".Problemy Medicinskoj Mikologii.19 (2): 95.
^Nenoff P, Herrmann J, Gräser Y (2007). "Trichophyton mentagrophytes sive interdigitale? A dermatophyte in the course of time".Journal der Deutschen Dermatologischen Gesellschaft.5 (3):198–202.doi:10.1111/j.1610-0387.2007.06180.x.PMID17338794.S2CID24939746.
^abHeidemann S, Monod M, Gräser Y (2010). "Signature polymorphisms in the internal transcribed spacer region relevant for the differentiation of zoophilic and anthropophilic strains ofTrichophyton interdigitale and other species ofT. mentagrophytes sensu lato".British Journal of Dermatology.162 (2):282–295.doi:10.1111/j.1365-2133.2009.09494.x.PMID19886885.S2CID31375222.
^abcTaghipour S, Pchelin IM, Zarei Mahmoudabadi A, et al. (2019). "Trichophyton mentagrophytes andT interdigitale genotypes are associated with particular geographic areas and clinical manifestations".Mycoses.62 (11):1084–91.doi:10.1111/myc.12993.PMID31444823.S2CID201631215.
^Weitzman, I.; Allderdice, P. W.; Silva-Hutner, M.; Miller, O. J. (1968). "Meiosis in Arthroderma benhamiae (=Trichophyton mentagrophytes)".Sabouraudia.6 (3):232–237.doi:10.1080/00362176885190441.PMID5679669.
