Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia

Toenail onychomycosis causes significant problems in public health and is more common among the elderly and immune-compromised populations. A previous culture-based survey of communal finely ground toenails from the east coast of Australia isolated 125 <i>T. interdigitale</i> but only on...

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Main Authors: Anjana C. Santosh, Danilla Grando, Ann C. Lawrie
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Journal of Fungi
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Online Access:https://www.mdpi.com/2309-608X/11/7/520
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author Anjana C. Santosh
Danilla Grando
Ann C. Lawrie
author_facet Anjana C. Santosh
Danilla Grando
Ann C. Lawrie
author_sort Anjana C. Santosh
collection DOAJ
description Toenail onychomycosis causes significant problems in public health and is more common among the elderly and immune-compromised populations. A previous culture-based survey of communal finely ground toenails from the east coast of Australia isolated 125 <i>T. interdigitale</i> but only one <i>T. rubrum</i>. This paucity of <i>T. rubrum</i> was surprising because it is one of the most common dermatophytes isolated worldwide. Our aim was to find out if <i>T. rubrum</i> was present but not cultured. DNA was extracted from ground toenails from the same samples. New specific primers were designed for the ITS region of <i>T. rubrum</i> that excluded <i>T. interdigitale</i> and vice versa. PCR with these new primers found <i>T. rubrum</i> as well as <i>T. interdigitale</i> in all ground toenail samples. This suggests that <i>T. rubrum</i> was present and common in the ground toenails. It was possibly missed by culture because it grows slowly and was overgrown by <i>T. interdigitale</i> and non-dermatophyte moulds. Alternatively, its viability may have declined earlier, during collection, treatment, or storage of the ground toenails. This has implications for studies of clinical materials, especially nails, as infection by <i>T. rubrum</i> (the most common dermatophyte) may be missed by culture, the main method used in pathology laboratories.
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spelling doaj-art-d80e85f6c432442fbc729344347e5eb42025-08-20T03:58:30ZengMDPI AGJournal of Fungi2309-608X2025-07-0111752010.3390/jof11070520Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern AustraliaAnjana C. Santosh0Danilla Grando1Ann C. Lawrie2School of Science, RMIT University, Bundoora, Melbourne 3083, AustraliaSchool of Science, RMIT University, Bundoora, Melbourne 3083, AustraliaSchool of Science, RMIT University, Bundoora, Melbourne 3083, AustraliaToenail onychomycosis causes significant problems in public health and is more common among the elderly and immune-compromised populations. A previous culture-based survey of communal finely ground toenails from the east coast of Australia isolated 125 <i>T. interdigitale</i> but only one <i>T. rubrum</i>. This paucity of <i>T. rubrum</i> was surprising because it is one of the most common dermatophytes isolated worldwide. Our aim was to find out if <i>T. rubrum</i> was present but not cultured. DNA was extracted from ground toenails from the same samples. New specific primers were designed for the ITS region of <i>T. rubrum</i> that excluded <i>T. interdigitale</i> and vice versa. PCR with these new primers found <i>T. rubrum</i> as well as <i>T. interdigitale</i> in all ground toenail samples. This suggests that <i>T. rubrum</i> was present and common in the ground toenails. It was possibly missed by culture because it grows slowly and was overgrown by <i>T. interdigitale</i> and non-dermatophyte moulds. Alternatively, its viability may have declined earlier, during collection, treatment, or storage of the ground toenails. This has implications for studies of clinical materials, especially nails, as infection by <i>T. rubrum</i> (the most common dermatophyte) may be missed by culture, the main method used in pathology laboratories.https://www.mdpi.com/2309-608X/11/7/520Onychomycosistinea unguiumtinea pedisdermatophytes<i>Trichophyton interdigitale</i><i>Trichophyton rubrum</i>
spellingShingle Anjana C. Santosh
Danilla Grando
Ann C. Lawrie
Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
Journal of Fungi
Onychomycosis
tinea unguium
tinea pedis
dermatophytes
<i>Trichophyton interdigitale</i>
<i>Trichophyton rubrum</i>
title Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
title_full Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
title_fullStr Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
title_full_unstemmed Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
title_short Specific Primers and Nested PCR Find <i>Trichophyton rubrum</i> Missed by Culture of Ground Toenails from Onychomycosis in Podiatric Patients in Eastern Australia
title_sort specific primers and nested pcr find i trichophyton rubrum i missed by culture of ground toenails from onychomycosis in podiatric patients in eastern australia
topic Onychomycosis
tinea unguium
tinea pedis
dermatophytes
<i>Trichophyton interdigitale</i>
<i>Trichophyton rubrum</i>
url https://www.mdpi.com/2309-608X/11/7/520
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