A simple and minimally-invasive device for skin sampling and molecular detection in cutaneous fungal infections

Skin fungal infections present a significant global disease burden worldwide and are difficult to treat due to their frequent recurrence. To date, we have witnessed significant advancements in the fungi detection using molecular methods; yet little attention has been given to the standard clinical practice of sample collection via skin scraping, which is operator and skill-dependent, and only limited to the surface. In this study, we evaluated the clinical utility of a previously reported sampling tool - microprojection array (MPA) as a minimally invasive sampling approach for molecular detection of fungi in patients with suspected skin infections. Skin samples collected using scrapes was similarly processed in comparison. Detection using pan-fungal qPCR enabled differentiation between samples infected with Trichophyton and Candida , whereas metagenomic sequencing analysis provided more detailed species-level identification—particularly for Candida albicans —and demonstrated greater sensitivity than microscopy and culture. Among clinically positive samples, both sampling methods showed comparable relative abundance profiles. Nevertheless, we observed variations in the detection of certain species between the two sampling approaches which suggests possible differences in the spatial distribution of these fungi. Overall the findings demonstrated the feasibility of combining MPA-based transepidermal sampling with established molecular detection methods to facilitate clinical fungal diagnosis.