<i>Trichophyton mentagrophytes</i> ITS genotype VIII and <i>Trichophyton indotineae</i>: A terminological maze, or is it?

Nenoff, P.; Uhrlaß, Silke; Verma, Shyam; Panda, Saumya

doi:10.25259/ijdvl_112_2022

Cited by 11 publications

(6 citation statements)

References 26 publications

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“…interdigitale complex, five anthropophilic genotypes of T. interdigitale are currently known, as well as 24 zoophilic and partly anthropophilic genotypes within the species T. mentagrophytes. 18,35 The new genotype XXV of T. mentagrophytes fits in here. There is also an intermediate or mixed anthropophilic and/or zoophilic genotype II* of T. interdigitale, which we were able to isolate in our study in Cambodia, too.…”

Section: Con Clus Ionsupporting

confidence: 52%

Dermatophytes and skin dermatophytoses in Southeast Asia—First epidemiological survey from Cambodia

Uhrlaß,

Mey,

Koch

et al. 2024

Mycoses

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BackgroundDermatomycoses count to the most frequent dermatoses in Cambodia.ObjectivesThe aim of this survey was to investigate the occurrence of dermatophytes in this Southeast Asian country.MethodsFrom June 2017 to July 2018, skin scrapings were taken from 67 patients with superficial dermatophytosis for mycological diagnostics. Identification of dermatophytes was confirmed by sequencing of the ‘internal transcribed spacer’—(ITS) region of the rDNA, and the gene of the Translation Elongation Factor (TEF)‐1α.ResultsPatients were suffering from tinea corporis and tinea inguinalis/cruris 42/67 (63%), tinea capitis/faciei 14/67 (21%), tinea corporis/capitis/faciei 6/67 (9%), tinea manuum/pedis 2/67 (3%), tinea pedis 2/67 (3%) and tinea manuum 1/67 (1%). Both, by culture and/or PCR, a dermatophyte was detected in 52 (78%) out of 67 samples. Culture positive were 42 (81%) of 52, PCR positive were 50 (96%). The following dermatophytes were found: Trichophyton (T.) rubrum, 36/52 strains (69%, 29 by culture), T. mentagrophytes/T. interdigitale (TM/TI) 9/52 (17%, six by culture) and Microsporum (M.) canis 5/52 strains (10%, by culture). One strain of Nannizzia (N.) incurvata 1/52 (2%) and N. nana 1/52 (2%) was isolated. Based on sequencing, we demonstrated that two T. mentagrophytes strains out of the nine TM/TI represented the new ITS genotype XXV Cambodia. We found one T. mentagrophytes strain genotype VIII (now, reclassified as T. indotineae). This isolate was terbinafine resistant, and it exhibited the amino acid substitution Phe397Leu in the squalene epoxidase. Three strains of T. interdigitale genotype II* were isolated.ConclusionThis is the first survey on epidemiology of dermatophytes in Cambodia. Currently, T. rubrum represents the most frequent species in Cambodia. One Indian strain genotype VIII T. mentagrophytes was found. A highlight was the first description of the new T. mentagrophytes genotype XXV Cambodia.

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Section: Con Clus Ionsupporting

confidence: 52%

Dermatophytes and skin dermatophytoses in Southeast Asia—First epidemiological survey from Cambodia

Uhrlaß,

Mey,

Koch

et al. 2024

Mycoses

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“…3,17,56,70 To date, twentyplus mutations of the squalene epoxidase gene have been reported. 4,17,25,33,[71][72][73] PCR testing post-treatment may be a more sensitive indicator of a 'cure' than a negative culture; further investigation of negative PCR as a proxy for mycological cure is needed, with an eye to possible PCR utility in determining when an antifungal therapy can be stopped. 74 Molecular analysis methods are fast and specific compared to culture but have limitations: few methods (for example, only specialized quantitative PCR) can indicate a viable species; tests may only look for a limited number of species; and tests may capture contaminant species as well as causative agents.…”

Section: Molecular Identification Methodsmentioning

confidence: 99%

“…Gene sequencing can also demonstrate point mutations, missense mutations, frame shifts and gene copy number in the genes encoding antifungal drug targets such as squalene epoxidase 3,17,56,70 . To date, twenty‐plus mutations of the squalene epoxidase gene have been reported 4,17,25,33,71–73 . PCR testing post‐treatment may be a more sensitive indicator of a ‘cure’ than a negative culture; further investigation of negative PCR as a proxy for mycological cure is needed, with an eye to possible PCR utility in determining when an antifungal therapy can be stopped 74 .…”

Section: Diagnosismentioning

confidence: 99%

Combatting antifungal resistance: Paradigm shift in the diagnosis and management of onychomycosis and dermatomycosis

Gupta

Talukder

Carviel

et al. 2023

Acad Dermatol Venereol

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Antifungal resistance has become prevalent worldwide. Understanding the factors involved in spread of resistance allows the formulation of strategies to slow resistance development and likewise identify solutions for the treatment of highly recalcitrant fungal infections. To investigate the recent explosion of resistant strains, a literature review was performed focusing on four main areas: mechanisms of resistance to antifungal agents, diagnosis of superficial fungal infections, management, and stewardship. The use of traditional diagnostic tools such as culture, KOH analysis and minimum inhibitory concentration values on treatment were investigated and compared to the newer techniques such as molecular methods including whole genome sequencing, and polymerase chain reaction. The management of terbinafine‐resistant strains is discussed. We have emphasized the need for antifungal stewardship including increasing surveillance for resistant infection.

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“…Species belonging to the Trichophyton mentagrophytes complex ( T. mentagrophytes, T. interdigitale and T. indotineae ) present the same morphological characteristics in laboratory culture media and are thus difficult to distinguish by phenotypic methods [ 1 ]. From 2008 to 2016, the mycology community dropped the distinction between Trichophyton interdigitale and T. mentagrophytes , and the only distinction made was between the origin of the isolate, which was either anthropophilic or zoophilic [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

“…After its emergence in India, T. indotineae spread into many countries, with cases reported in Japan [ 11 ], Canada [ 14 ], and in European countries such as Germany [ 15 ], Switzerland [ 5 ], Greece [ 16 ], Denmark [ 17 ], and France [ 9 , 18 ]. Facing the impressive development of this dermatophytosis agent in India, and later on in other countries, mycologists proposed to include this disease in the list of emerging infectious diseases [ 1 ]. The spread of this new species makes it necessary to develop diagnostic tools capable of accurately differentiating it from the other species belonging to the T. mentagrophytes complex which are also responsible for tinea cruris and tinea corporis.…”

Section: Introductionmentioning

confidence: 99%

MALDI-TOF Mass Spectrometry Online Identification of Trichophyton indotineae Using the MSI-2 Application

Normand

Moreno-Sabater

Jabet

et al. 2022

JoF

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Trichophyton indotineae is an emerging pathogen which recently spread from India to Europe and that is more prone than other species of the Trichophyton mentagrophytes complex to show resistance to terbinafine, resulting in the necessity of rapid identification. Here, we improved the online MSI-2 MALDI-TOF identification tool in order to identify T. indotineae. By multiplying the culture conditions (2 culture media and 6 stages of growth) prior to protein extractions for both test isolates and reference strains, we added 142 references corresponding to 12 strains inside the T. mentagrophytes complex in the online MSI-2 database, of which 3 are T. indotineae strains. The resulting database was tested with 1566 spectra of 67 isolates from the T. mentagrophytes complex, including 16 T. indotineae isolates. Using the newly improved MSI-2 database, we increased the identification rate of T. indotineae from 5% to 96%, with a sensitivity of 99.6%. We also identified specific peaks (6834/6845 daltons and 10,634/10,680 daltons) allowing for the distinction of T. indotineae from the other species of the complex. Our improved version of the MSI-2 application allows for the identification of T. indotineae. This will improve the epidemiological knowledge of the spread of this species throughout the world and will help to improve patient care.

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Trichophyton mentagrophytes ITS genotype VIII and Trichophyton indotineae: A terminological maze, or is it?

Cited by 11 publications

References 26 publications

Dermatophytes and skin dermatophytoses in Southeast Asia—First epidemiological survey from Cambodia

Dermatophytes and skin dermatophytoses in Southeast Asia—First epidemiological survey from Cambodia

Combatting antifungal resistance: Paradigm shift in the diagnosis and management of onychomycosis and dermatomycosis

MALDI-TOF Mass Spectrometry Online Identification of Trichophyton indotineae Using the MSI-2 Application

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