An investigation on non-invasive fungal sinusitis; Molecular identification of etiologic agents.

BACKGROUND: Fungal sinusitis is increasing worldwide in the past two decades. It is divided into two types including invasive and noninvasive. Noninvasive types contain allergic fungal sinusitis (AFS) and fungus ball. AFS is a hypersensitivity reaction to fungal allergens in the mucosa of the sinonasal tract in atopic individuals. The fungus ball is a different type of noninvasive fungal rhinosinusitis which is delineated as an accumulation of debris and fungal elements inside a paranasal sinus. Fungal sinusitis caused by various fungi such as Aspergillus species, Penicillium , Mucor , Rhizopus , and phaeohyphomycetes. The aim of the present study is to identify fungal species isolated from noninvasive fungal sinusitis by molecular methods.

MATERIALS AND METHODS: During 2015-2016, a total of 100 suspected patients were examined for fungal sinusitis. Functional endoscopic sinus surgery was performed using the Messerklinger technique. Clinical samples were identified by phenotypic and molecular methods. Polymerase chain reaction (PCR) sequencing of ITS1-5.8S-ITS2 region and PCR-restriction fragment length polymorphism with Msp I restriction enzyme was performed for molecular identification of molds and yeasts, respectively.

RESULTS: Twenty-seven out of 100 suspected cases (27%) had fungal sinusitis. Nasal congestion (59%) and headache (19%) were the most common clinical signs among patients. Fifteen patients (55.5%) were male and 12 patients (44.5%) were female. Aspergillus flavus was the most prevalent fungal species (26%), followed by Penicillium chrysogenum (18.5%) and Candida glabrata species complex (15%).

CONCLUSION: Since clinical manifestations, computed tomography scan, endoscopy, and histopathological findings are very nonspecific in AFS and fungus ball; therefore, molecular investigations are compulsory for precise identification of etiologic agents and appropriate management of these fungal infections.