Pets in the household increase ocular surface microbiome exchanges between dog and owner.

The evidence of antibiotic-resistant bacteria-sharing between pets and owners and the increasing number of households with pets call attention to microbial exchanges between animals and humans at home. Sharing of allergic traits and of skin, oral, and gut microbiomes between dogs and owners has been demonstrated in multiple studies, highlighting the existence and importance of non-pathogenic microbial exchanges, and calling for a One Health approach to study the microbiomes. This study investigates sharing of ocular surface microbiome between dogs and owners by characterizing dog and owner ocular microbiomes, and evaluating the impact of several lifestyle factors on microbiome similarities between them. To this aim, conjunctival swabs were collected from 15 dogs and their owners for subsequent DNA extraction and 16S rRNA V3-V4 regions sequencing. Microbiome composition and alpha diversity were determined for dogs and owners. Beta diversity was estimated with weighted UniFrac distance, unweighted UniFrac distance, and Bray-Curtis dissimilarity. Dog-owner distances, i.e. beta diversity in each dog-owner pair, were calculated to estimate the level of similarity between dog and owner microbiomes. The impact of several lifestyle factors on microbiome similarities between dog and owner was investigated. Dog and owner microbiomes were found to be similar in overall composition, harboring the same main phyla and families, albeit forming two distinct clusters and dogs having a significantly more diverse microbiome. Small dogs tended to share more microbiome with their owner than large dogs. Pairs cohabiting with other pets had a microbiome composition significantly more similar than the ones who did not.