Comparison of the Oral Microbiomes of Canines and Their Owners Using Next-Generation Sequencing

Abstract

The oral microbiome, which is closely associated with many diseases, and the resident pathogenic oral bacteria, which can be transferred by close physical contact, are important public health considerations. Although the dog is the most common companion animal, the composition of the canine oral microbiome, which may include human pathogenic bacteria, and its relationship with that of their owners are unclear. In this study, 16S rDNA pyrosequencing was used to compare the oral microbiomes of 10 dogs and their owners and to identify zoonotic pathogens. Pyrosequencing revealed 246 operational taxonomic units in the 10 samples, representing 57 genera from eight bacterial phyla. Firmicutes (57.6%), Proteobacteria (21.6%), Bacteroidetes (9.8%), Actinobacteria (7.1%), and Fusobacteria (3.9%) were the predominant phyla in the human oral samples, whereas Proteobacteria (25.7%), Actinobacteria (21%), Bacteroidetes (19.7%), Firmicutes (19.3%), and Fusobacteria (12.3%) were predominant in the canine oral samples. The predominant genera in the human samples were Streptococcus (43.9%), Neisseria (10.3%), Haemophilus (9.6%), Prevotella (8.4%), and Veillonella (8.1%), whereas the predominant genera in the canine samples were Actinomyces (17.2%), Unknown (16.8), Porphyromonas (14.8), Fusobacterium (11.8), and Neisseria (7.2%). The oral microbiomes of dogs and their owners were appreciably different, and similarity in the microbiomes of canines and their owners was not correlated with residing in the same household. Oral-to-oral transfer of Neisseria shayeganii, Porphyromonas canigingivalis, Tannerella forsythia, and Streptococcus minor from dogs to humans was suspected. The finding of potentially zoonotic and periodontopathic bacteria in the canine oral microbiome may be a public health concern.

Fig 1. Rarefaction curve for 10 oral microbiome samples.

Curves were plotted at a cutoff of 0.03 for each sample.

Fig 2. Relative distribution of sequences in the OTUs of the 10 oral samples.

Phyla corresponding to more than 0.5% of the sequences determined from the mean distribution of phyla.

Fig 3. Relative distribution of sequences in the OTUs in 10 oral samples.

Distribution at the genus level.

Fig 4. Phylogenetic tree showing the similarity in the oral microbiota of canines and their owners based on the neighbor-joining methods.

Fig 5. Three-dimensional principal coordinate analysis (PCoA) plot of samples using the weighted UniFrac distance metric.

Percentage of the diversity distribution explained by each axis is indicated on the fig.