Translation elongation factor ۱-alpha gene as a marker for diagnosing of candidal onychomycosis

Background and Purpose: Culture-based identification methods have been the gold standard for the diagnosis of candidal onychomycosis. Molecular technologies, such as polymerase chain reaction (PCR) assays, can provide an alternative for the rapid detection of Candida species. The present study was conducted to investigate a pan-Candida PCR assay based on the translation elongation factor ۱-alpha (TEF-۱α) gene for the detection of the most prevalent pathogenic Candida species. Materials and Methods: For the purpose of the study, an optimized pan-Candida PCR primer pair was designed, and the target was amplified and sequenced. The analytical and clinical diagnostic performance of the designed primers was tested using ۱۷ reference strains, ۱۳۷ nail scrapings suspected of onychomycosis, and ۱۰ healthy nail specimens. Results: The use of the universal pan-Candida primers designed on TEF-۱α gene resulted in the successful amplification of a ۲۷۰-base pair fragment in all Candida species tested, except for C. glabrata, and reacted neither with other fungi nor with E. coli. The sequence difference count matrix showed poor insertion/deletion differences (۰-۲ nt) among Candida species. Among ۱۳۷ nail specimens, ۳۵% (n=۴۸), ۳۰.۷% (n=۴۲), and ۴۰.۱% (n=۵۵) of the samples were found to be positive by direct microscopy, culture, and pan-Candida PCR, respectively. Conclusion: Based on the findings, the PCR-based detection targeting the DNA TEF-۱α gene is a rapid and simple procedure for the diagnosis of candidal onychomycosis directly from nail sample.

کلیدواژه ها:

Candidal onychomycosis ، Pan-Candida PCR assay ، Translation elongation factor ۱-alpha