The influence of adenoidal microbiome on children with chronic otitis media with effusion differs according to ages
Otitis media with effusion(OME) is defined as the presence of fluid in middle ear without acute inflammation. The most episodes of OM resolve quickly without complication. However, chronic OME (COME, more than 3 months), a subtype of OM, influence on child development. The microbiome in adenoid can be one of the factors in the pathogenesis of COME. However, the influence of adenoid microbiome in COME is still unclear. We collected adenoid swab and feces from childhood (2-12 years old) with COME (adenoid n=15, feces n=14) and control group (adenoid n=18, feces n=18). For collected sample, we analyzed microbiome using whole metagenome shotgun sequencing. The adenoid microbiota was affected by middle ear fluid type, phenotype and age, whereas gut microbiota only was affected by middle ear fluid type. In particular, the variation of adenoid microbiota according to middle ear fluid type was associated to COME. The microbiota of control group in adenoid was altered according to age (P < 0.05). This alteration did not occur   in patients (serous and mucoid). When we split the age groups into 6-12 and 2-5 years in adenoid, the difference of microbiota only indicated in 6-12 years. In 6-12 years, S. pneumoniae and H. influenzae was indicator species in mucoid group (P < 0.05). The network analysis (Fastspar) revealed that interspecies correlation was affected by severity of COME. Similarly, functional alterations in adenoid microbiome was only observed in 6-12 years. Overall, these data revealed that COME in 2-5 years was significantly associated with other factors than adenoid microbiome. The gene families that suppress inflammation were negatively correlated with S. pneumoniae and H. influenzae. Results in this study can extend our understanding about the influence of microbiome in the pathogenesis of COME.