Differences of mouth microbiomes in healthy dogs and those with periodontitis

Periodontitis is a serious gum infection that damages the soft tissue and destroys the bone supporting the teeth. The oral microbiome shares space in the body and helps in transport of ionic minerals from the saliva to the surface of teeth and aid in their remineralization. There is a lack of the data how do oral microbiota changes can affect oral health of the dogs. The aim of this study was to compare oral microbiomes of healthy dogs and those with periodontal disease in the same geographical location (Kaunas county, Lithuania). Prior to the commencement of the study, written informed consent was obtained from the owner of each dog. All procedures were performed according to the applicable international, national, and institutional guidelines for the care and use of animals. Ethics approval was obtained from the Bioethics Center, Lithuanian University of Health Sciences, Kaunas, Lithuania (approval number 2024-BEC3-T005). Sixty dogs of different age and breed brought to the veterinary clinic were examined for their oral health. In cases of suspected periodontitis, X-rays were used to evaluate the level of of the disease. Only six dogs were treated as healthy individuals without signs of periodontitis (stage PD1), whereas 30 dogs had signs of advanced periodontitis (stage PD3–PD4) and required further radical treatment. Therefore, two cohort of dogs (healthy), and those with periodontal disease (untreated for at least six months) were selected for further study. Clinical material using sterile swabs was taken from teeth with further DNA extraction and shotgun sequencing on the Illumina HiSeq system platform. Differences in microbial taxonomy were evaluated between the groups. The most prevalent microorganisms in healthy dogs were Porphyromonas gulae, P. cangingivalis, P. canoris, P. gingivicanis, Corynebacterium canis, Tannerella forsythia, Lampropedia sp.003703703475 Arachnia sp.003932855, Bergeyella zoohelcum, Desulfomicrobium orale and Moraxella sp.002224245. In dogs with advanced periodontal disease the most prevalent species were Porphyromonas gulae, P. crevioricanis, P. cangingivalis Prevotella spp., Tannerella forsythia and Bacteroides heparinolyticus (p<0.05). In conclusion, both healthy dogs and dogs with periodontitis carry a part of the same microbial species however, some of the species including Porphyromonas crevioricanis, Prevotella spp. and Bacteroides heparinolyticus in diseased dogs were detected in high amounts. Etiological significance of aforementioned species for the development of periodontal disease in dogs and the risk to dog owners and other aimals should be further studied.