(ÖGDV Jahrestagung 2023 - Posterpreis)
I. Indikova, K. Schwarz, M. Sharifi, K. Loydl, N.Hasanbegovic Tandir, C. Heller-Vitouch, A. Stary
Outpatients Centre for Diagnosis of Infectious Venero-dermatological Diseases, Vienna, Austria
Objectives and aim:
DNA amplification is a sensitive method for identifying infections. Although fungal culture is a well-established method for diagnosing fungi, the PCR is a highly sensitive molecular technology and provides results in short time. The study's objective was to compare multiplex qPCR and culture using patient samples from various cutaneous regions and nail scrapings.
Patients and Methods:
A total of 971 samples (402 from men, 569 from women) from the skin (255; 26.3%) and nails (716; 73.7%) were examined. Samples from patients referred to the Outpatients Centre (849; 87.4%) or mailed (122; 12.6%) were simultaneously analysed by cultivation in fungal culture media (Sabouraud agar at 28°C for 21 days), KOH direct tests and by multiplex qPCR (DermaGenius, Pathonostic).
Results:
qPCR demonstrated the presence of dermatophyte DNA in 359 (37%) of 971 samples from nails (72.7%) and skin (27.3%). Of the qPCR-positive samples, growth of the dermatophyte was observed in 30.9% for nails and 18.1% for skin scrapings. Both technologies yielded positive results in 176 (18.1%) of all samples tested, leaving 183 infections (51%) missed by culture. The most common species was T. rubrum, detected in 11.3% by culture and 25.7% by qPCR.
Conclusion:
Our results demonstrate the high sensitivity of qPCR. It overcomes cumbersome culture methods. Importantly, one half of dermatophyte infections were detected only by qPCR. The rapid and accurate performance of qPCR allows timely and appropriate treatment allocation. Cultivation methods remain important for antifungal resistance testing and non-dermatophyte diagnosis.
