Mycobiome in the Middle Ear Cavity with and Without Otitis Media with Effusion

Objective: No data have yet been published revealing the composition and the diversity of fungal communities (mycobiome) in the human middle ear cavity. The presented study investigated the mycobiome in the middle ear cavities of individuals with healthy middle ears and patients with otitis media with effusion. Methods: A total of 77 middle ear and four adenoid samples were collected from 47 individuals (35 children and 12 adults) in Group 1 and from 20 children in Group 2. The mycobiome profile was analyzed with nuclear ribosomal internal transcribed spacer 2 (ITS2) based metabarcoding using an Illumina MiSeq metagenomics kit. Results: ITS2-based metabarcoding detected 14 different genera and 17 different species with a mean relative abundance of >= 1% in the samples analyzed. Mycobiome profile was similar between the adenoid tissue and the middle ear cavity, between Groups 1 and Group 2, and between children and adults. Fusarium, Stemphylium, Candida, and Cladosporium were the most abundant genera detected in all samples. The mean relative abundances of the genera Candida and Fusarium were remarkably higher in Group 2 compared to Group 1. Conclusion: The species Candida glaebosa, Candida cretensis, Aspergillus ruber, Penicillium desertorum, and Rhizopus arrhizus were significantly more abundant in patients with otitis media with effusion (OME), raising the possibility that they affect the pathogenesis of OME.