The microbiomes of adenoid and middle ear in children with otitis media with effusion and hypertrophy from a tertiary hospital in China

Abstract Introduction Otitis media with effusion (OME) is one of the most common pediatric diseases worldwide. Several studies have analyzed the diversity of the microbiomes found in the middle ear effusions (MEEs) of populations from developed countries. However, no microbiological studies of MEEs from Chinese children with OME have been reported. This study investigated the middle ear and adenoid microbiological profiles of children with OME, and compared the microbial flora of the adenoid between children with and without otitis media. Methods MEEs and adenoid swabs were acquired from 15 children undergoing ventilation tube insertion and adenoidectomy. Adenoid swabs from 15 patients with no ear disease were used as controls. Samples were analyzed by 16S rRNA sequencing. Operational taxonomic units (OTUs) abundance information were normalized. Alpha diversity analyses were used to assess the richness and diversity of the microbial community for each sample. Beta diversity analyses were used to determine the inter-group variability between microbiome structure. Results Based on the mean relative abundance, the MEEs were dominated by Haemophilus (14.75%), Staphylococcus (9.37%) and Halomonas (7.85%), and the bacterial compositions of the adenoids in the OME groups were dominated by Haemophilus (21.87%), Streptococcus (19.65%), and Neisseria (5.8%). The bacterial compositions in the adenoids of the controls were dominated by Haemophilus (15.96%), Streptococcus (13.33%), and Moraxella (12.28%). Alpha diversity analyses showed that there were no significant differences in microbiome richness or diversity between the middle ear effusions (TM) and adenoids (TA) of OME subjects. Adenoid samples from OME patients (TA) and control patients (CA) were also similar. Beta diversity analyses showed that the microbiomes of the adenoids in OME patients were also similar to that of controls. However, the microbiome structure of middle ear effusions was dissimilar to those of the adenoids in OME patients according to beta diversity analyses. Conclusions Our results confirmed the microbial diversity of MEEs among Chinese children. However, the dissimilar microbiome composition between samples taken from the surface of the adenoids and from the middle ear effusions challenges the conventional theory that the adenoid serves as a microbial reservoir in children with otitis media with effusion.