Association Between Ocular Microbiomes of Children and Their Siblings and Parents

Purpose: This study aims to investigate the association of ocular microbiomes between children and their parents and siblings. Methods: An observational study was conducted at family units, involving 114 children and 131 parents, with conjunctival swab samples collected and analyzed using 16S rDNA high-throughput sequencing. Comparative analyses, diversity indexes, and distance measures were used to assess microbial community differences. Results: Children's ocular microbiomes are more similar to their parents than unrelated adults (P < 0.001 for both Bray-Curtis and Jensen-Shannon distances). Additionally, children's ocular microbiomes exhibited greater similarities with their siblings than with unrelated children (P < 0.001). However, couples who lived in the same family showed no more similarity in the composition of their ocular microbiota than did unrelated individuals (Bray-Curtis distance P = 0.7; Jensen-Shannon distance P = 0.47). Four genera, Aquabacterium, Corynebacterium, Staphylococcus and Streptococcus, were highly shared between parental and children's ocular microbiomes (>70% shared rate). A relatively weak correlation was observed between the age of child and the similarity comparing child's and adults' microbiomes. The interquartile range of parental contribution to a child's ocular microbiome was 11.2% (first quartile) to 33.0% (third quartile), suggesting a substantial majority attributable to unknown factors. Conclusions: Children's ocular microbiome is associated with that of their siblings and their parents, with this association showing a small tendency to increase with the age of the children. These findings highlight the importance of considering familial and environmental contexts in future microbiological research.