Reference : Validation of the DermaGenius Nail plus multiplex assay, a new commercial PCR assay d...
Scientific congresses and symposiums : Paper published in a journal
Human health sciences : Immunology & infectious disease
Human health sciences : Laboratory medicine & medical technology
http://hdl.handle.net/2268/189859
Validation of the DermaGenius Nail plus multiplex assay, a new commercial PCR assay developed for the detection and identification of dermatophyte and Candida in nails
English
[fr] Validation du kit dermagenius Nail plus, un nouveau kit commercial pour la détection et identification des dermatophytes et Candida dans les ongles
Hayette, Marie-Pierre mailto [Université de Liège > Département des sciences biomédicales et précliniques > Bactériologie, mycologie, parasitologie, virologie >]
GRAIDE, Hélène [Centre Hospitalier Universitaire de Liège - CHU > > Microbiologie clinique >]
ADJETEY BAHUN, Akolé mailto [Centre Hospitalier Universitaire de Liège - CHU > > Microbiologie clinique >]
Arrese Estrada, Jorge mailto [Université de Liège > Département des sciences biomédicales et précliniques > Anatomie et cytologie pathologiques >]
Gaajetaan, Giel mailto []
Van Tegelen, Dennis []
Kamperman, Tim []
Simons, Guus mailto []
Dingemans, Gijs mailto []
Oct-2015
Mycoses
Blackwell Publishing
58
suppl 4
abstract book, 7th Trends in Medical Mycology Organised under the auspices of EORTC-IDG and ECMM 9–12 October 2015, Lisbon, Portugal
223
Yes (verified by ORBi)
No
International
0933-7407
1439-0507
Berlin
Germany
7th Trend in Medical Mycology (TIMM)
9-12 october 2015
Joint meeting of European Confederation of Medical Mycology and EORTC Infectious Diseases Group
Lisbon
Portugal
[en] Nails ; PCR ; commercial kit ; dermagenius ; clinical validation
[en] Objectives
Superficial dermatophytosis is the most common fungal infection in humans. Diagnosis of dermatophytosis is currently based on microscopy or histology associated with culture on specific agar media. However, direct microscopy lacks specificity and culturing has a long turn-around-time of 2-4 weeks. These limitations can be prevented by the use of molecular diagnostics. The DermaGenius (DG) multiplex kit (PathoNostics, The Netherlands) is a new commercial realtime-PCR kit, which can differentiate various dermatophytes species including the nail pathogens T. rubrum, T. mentagrophytes, T. interdigitale and 2 Candida species (C. albicans and C. parapsilosis). This study aimed at the validation of the kit on nails clippings. Results were compared with histology and culture data.
Methods
A set of 76 nail clippings was collected from 76 patients attending the dermatology consultation at the University Hospital of Liege on suspicion of onychomycosis. All nails were divided in three pieces for histology, culture and the PCR multiplex assay. Histologic preparations were stained with PAS staining. Cultures were performed on 2 different Sabouraud agar medium slants (bioMérieux). The DNA extraction protocol used a proteinase K pre-treatment followed by an automated DNA-extraction (EasyMag, bioMérieux). An Internal Control (IC) was included to monitor for PCR inhibition or manual errors. The realtime-PCR amplification was performed with the DG kit on a Rotor-Gene Q instrument (Qiagen) by using quantitative amplification and melting curve analysis.
Results
In total, 35 of 76 cases (46%) were classified as confirmed onychomycosis based on positive microscopy (M+) with or without positive culture (C+) or just by positive culture of a confirmed pathogen. Based on negative microscopy (M-) and negative culture of a confirmed pathogen, 41 cases (54%) were reported as non-fungal onychodystrophy. Agreement between DermaGenius (DG) and culture was found in 52% of the cases while 86% agreement was reported when comparing positive DG with confirmed onychomycosis. Three positive cultures (microscopy negative) were not detected by DG (2 T. rubrum, 1 C. albicans). However, DG could detect 7 additional infections (9%). Eleven discrepancies DG+/C+ were determined which could be positively confirmed in favour of DG result by ITS sequence analysis. Most discrepancies could be explained by fungal/yeast species overgrowing the agar slant, including species of Candida, Fusarium, Trichosporon, which were not considered as the source of infection.
Conclusion
The DermaGenius Nail plus multiplex was able to detect the most prevalent pathogenic dermatophytes species in clinical nail specimens and proved to be more sensitive and specific than culture and direct microscopy. The DNA extraction procedure has been shown to work efficiently in diagnostics which enables the physician in charge of the patient to start a dedicated treatment rapidly.
National reference center for mycosis Liège Belgium
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/189859

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