Abstract | BACKGROUND:
Onychomycosis is estimated to occur in approximately 10% of the global population, with most cases caused by Trichophyton rubrum. Some persistent onychomycosis is caused by mixed infections of T rubrum and one or more co-infecting nondermatophyte molds ( NDMs). In onychomycosis, T rubrum strain types may naturally switch and may also be triggered to switch in response to antifungal therapy. T rubrum strain types in mixed infections of onychomycosis have not been characterized. METHODS: T rubrum DNA strains in mixed infections of onychomycosis containing co-infecting NDMs were compared with a baseline North American population through polymerase chain reaction amplification of ribosomal DNA tandemly repetitive subelements (TRSs) 1 and 2. The baseline DNA strain types were determined from 102 clinical isolates of T rubrum. The T rubrum DNA strain types from mixed infections were determined from 63 repeated toenail samples from 15 patients. RESULTS: Two unique TRS-2 types among the clinical isolates contributed to four unique TRS-1 and TRS-2 strain types. Six TRS-1 and TRS-2 strain types represented 92% of the clinical isolates of T rubrum. Four TRS-1 and TRS-2 strain types accounted for 100% of the T rubrum within mixed infections. CONCLUSIONS: Four unique North American T rubrum strains were identified. In support of a shared ancestry, the T rubrum DNA strain types found in mixed infections with NDMs were among the most abundant types. A population of T rubrum strains in mixed infections of onychomycosis has been characterized, with more than one strain detected in some nails. The presence of a co-infecting NDM in mixed infections may contribute to failed therapy by stabilizing the T rubrum strain type, possibly preventing the antifungal therapy-induced strain type switching observed with infections caused by T rubrum alone.
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Authors | Aditya K Gupta, Kerry-Ann Nakrieko |
Journal | Journal of the American Podiatric Medical Association
(J Am Podiatr Med Assoc)
Vol. 110
Issue 6
(Nov 01 2020)
ISSN: 1930-8264 [Electronic] United States |
PMID | 32810210
(Publication Type: Journal Article)
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Chemical References |
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Topics |
- Arthrodermataceae
(genetics, isolation & purification)
- Coinfection
- DNA, Fungal
(genetics)
- Humans
- Onychomycosis
(diagnosis)
- Polymerase Chain Reaction
- Trichophyton
(genetics, isolation & purification)
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