Contribution of molecular tools for the diagnosis and epidemiology of fungal chronic rhinosinusitis

Pauline Comacle (1) , Sorya Belaz (2, 1) , Franck Jegoux (3) , Christophe Ruaux (4) , François Le gall (5) , Jean-Pierre Gangneux (2, 1) , Florence Robert-Gangneux (2, 1)

1 Service de Parasitologie-Mycologie [Rennes]
2 Irset - Institut de recherche en santé, environnement et travail
3 Service d'ORL et de chirurgie maxillo-faciale [Rennes] = ENT Head and Neck Surgery [Rennes]
4 Clinique mutualiste La Sagesse
5 Centre Hospitalier Universitaire de Rennes [CHU Rennes] = Rennes University Hospital [Ponchaillou]

Chronic rhinosinusitis (CRS) rank second at chronic inflammatory diseases in industrialized countries and are an important public health concern. Diagnosis relies on a set of arguments including clinical signs, imaging, histopathologic and mycological analyses of sinus specimens, collected during nasal endoscopy. The sensitivity of fungal cultures is reported to be poor, even when direct examination is positive, thus the epidemiology of fungal chronic sinusitis is ill-known. This study evaluated the sensitivity of molecular diagnosis in 70 consecutive samples (61 patients with CRS) analysed at the University Hospital of Rennes during a 3-year period. DNA detection was performed using a conventional PCR method targeting the ITS1/ITS2 sequence and the resulting amplification products were sequenced. Fungal CRS was proven in 42 patients (69%), of which only 20 (48%) had a positive culture. 37/42 (88%) patients were diagnosed with a fungus ball, 3 with allergic fungal CRS and 2 with undetermined fungal CRS. PCR was positive in all 42 cases and direct sequencing allowed to identify fungi in all cases but one, and detected multiple infection in 3. Aspergillus fumigatus was present in 69% of patients; Cladosporium cladosporoides in 9.5%, Scedosporium sp., A. nidulans and A. flavus in 7% each. In 2/19 patients with negative direct examination, sequencing analysis revealed the presence of Capnobotryella sp. and C. cladosporoides, in clinical settings compatible with fungal sinusitis. In conclusion, ITS1/ITS2 PCR had a twice better sensitivity than culture, and combined sequencing provides accurate epidemiological data on fungal CRS.

Mots clés: fungi; PCR; sequence analysis; chronic rhinosinusitis; ITS1/ITS2

Domaines: Maladies infectieuses; Organes des sens; Mycologie

Pauline Comacle, Sorya Belaz, Franck Jegoux, Christophe Ruaux, François Le gall, et al.. Contribution of molecular tools for the diagnosis and epidemiology of fungal chronic rhinosinusitis. Medical Mycology, 2016, 54 (8), pp.794 - 800. ⟨10.1093/mmy/myw041⟩. ⟨hal-01383632⟩