Comparative analysis of onychomycosis in Puerto Rico using molecular and conventional approaches

Onychomycosis is the most prevalent nail ailment in adults, accounting for 50% of all nail infections. Derma-tophyte fungi are the primary cause, but non-dermatophyte molds (NDM) and yeasts can also cause onycho-mycosis. It remains important to precisely determine the fungal cause of onychomycosis since the response to current treatments may vary between fungal classes. Real-time polymerase chain reaction (qPCR) has become a widespread tool for detecting fungal organisms for diagnosis due to its sensitivity and ability to detect down to the species level. This retrospective study aims to evaluate the qPCR Onycho+ test for derma-tophyte detection using remnants of toenails from a cohort of patients from Puerto Rico. Two hundred forty-two toenail samples submitted for histological examination via Periodic acid Schiff (PAS) staining for sus-pected onychomycosis were analyzed by the Onycho+ test and Sanger sequencing of the internal transcribed spacer (ITS-2). Compared to the gold standard Sanger sequencing method, the Onycho+ test reported an agreement of 91.39%, a sensitivity of 100% and a specificity of 84.5% in detecting dermatophytes, superior to the histology method which had a 69.53% agreement, 85.1% sensitivity and 57.1% specificity. The distribution of fungal organisms detected in this cohort shows a dermatophyte majority but a higher-than-expected pro -portion of NDMs. Nails negative for the Onycho+ test and positive for histology were mostly NDMs. This study demonstrates that the clinical performance of the Onycho+ test is superior to histology in detecting dermatophytes and that a combination of Onycho+ and histology can result in a higher clinical accuracy.& COPY; 2023 The Authors. Published by Elsevier Masson SAS on behalf of SFMM. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)