[Do the new molecular assays-microarray and realtime polymerase chain reaction-for dermatophyte detection keep what they promise?]

Abstract

In this study, a novel real-time polymerase chain reaction (PCR) assay (DermaGenius®2.0, PathoNostics BV, Maastricht, The Netherlands) and a recently developed microarray test (EUROArray Dermatomycosis, Euroimmun, Lübeck, Germany) were evaluated regarding their diagnostic specificity to identify dermatophyte DNA. The tests were compared to conventional methods and sequencing. The microarray Dermatomycosis test allows the detection of 50 dermatophytes and definitive identification of 23 dermatophyte species, 6 yeasts and moulds combined in one test. In comparison, real-time PCR is able to identify 11 dermatophytes and one yeast at the species level. Using the EUROArray, 22 out of 24 dermatophyte species were correctly identified. Using real-time PCR, 9 out of the 11 different dermatophytes included in the test kit were correctly identified. Both molecular tests for detection and differentiation of dermatophytes are useful tools for daily clinical practice. The real-time PCR test does not detect as many species, and specificity is slightly lower. However, real-time PCR is a very fast and easy to perform test, especially since no post-PCR step is necessary. Real-time PCR detects the most frequent dermatophytes like T. rubrum, T. interdigitale, and M. canis without any problems. The EUROArray is more elaborate to perform in the lab, due to the hybridization step. However, the EUROArray shows higher specificity and can detect a much broader range of causative agents, including rare species, in dermatomycology.

Keywords: Diagnostics; Fungal pathogen detection; Microsporum ferrugineum; Trichophyton rubrum; Trichophyton soudanense.