Characterization of ocular and nasopharyngeal microbiome in allergic rhinoconjunctivitis

Allergic rhinoconjunctivitis (ARC) is a prevalent allergic condition in the pediatric population. Microbial dysbiosis has increasingly been recognized to influence on host immunity and allergic diseases. However, the microbial profile of ARC has not been characterized. This cross-sectional study aims to evaluate the changes in nasal and ocular surface microbiome of children with ARC.

Ocular and nasopharyngeal swabs were collected from controls and pediatric ARC cases for 16S rRNA amplicon sequencing. The bacterial community profile was analyzed. The correlation of the microbial diversity with the ARC-related clinical scores was studied.

A total of 23 patients with ARC and 17 healthy controls were recruited;30 were ocular samples (15 controls vs 15 ARC), while 40 were nasal samples (17controls vs 23 ARC) The alpha diversity of nasopharyngeal microbiome was significantly higher in ARC patients than healthy controls (P < 0.01), but not for ocular microbiome. The clinical scores in all subjects were negatively correlated with the Shannon diversity for ocular (P = 0.014) and positively correlated with nasopharyngeal (P = 0.010) microbiome. While the ocular microbiome remained significantly distinct from nasopharyngeal microbiome in terms of both alpha and beta diversity in both healthy subjects and ARC patients, significant differences of relative abundance of certain phyla (Bacteroidetes, Cyanobacteria, and Deinococcus-Thermus) and genera (Dolosigranulum and Moraxella) between nasal and ocular surfaces were only detected in healthy controls, but not in the ARC subjects, suggesting the microbial composition at both body sites becoming more similar at disease state.

This study reported (a) a higher alpha diversity in ocular than nasopharyngeal microbiome in both ARC patients and controls, and (b) nasopharyngeal microbiome became more diverse in ARC patients than in controls. Our results suggested an interaction of the microbiome between ocular and nasal compartments in patients with ARC.