Microbiota populations in supragingival plaque, subgingival plaque, and saliva habitats of adult dogs

Abstract

Background: Oral diseases are common in dogs, with microbiota playing a prominent role in the disease process. Oral cavity habitats harbor unique microbiota populations that have relevance to health and disease. Despite their importance, the canine oral cavity microbial habitats have been poorly studied. The objectives of this study were to (1) characterize the oral microbiota of different habitats of dogs and (2) correlate oral health scores with bacterial taxa and identify what sites may be good options for understanding the role of microbiota in oral diseases. We used next-generation sequencing to characterize the salivary (SAL), subgingival (SUB), and supragingival (SUP) microbial habitats of 26 healthy adult female Beagle dogs (4.0 ± 1.2 year old) and identify taxa associated with periodontal disease indices.

Results: Bacterial species richness was highest for SAL, moderate for SUB, and lowest for SUP samples (p < 0.001). Unweighted and weighted principal coordinates plots showed clustering by habitat, with SAL and SUP samples being the most different from one another. Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, Actinobacteria, and Spirochaetes were the predominant phyla in all habitats. Paludibacter, Filifactor, Peptostreptococcus, Fusibacter, Anaerovorax, Fusobacterium, Leptotrichia, Desulfomicrobium, and TG5 were enriched in SUB samples, while Actinomyces, Corynebacterium, Leucobacter, Euzebya, Capnocytophaga, Bergeyella, Lautropia, Lampropedia, Desulfobulbus, Enhydrobacter, and Moraxella were enriched in SUP samples. Prevotella, SHD-231, Helcococcus, Treponema, and Acholeplasma were enriched in SAL samples. p-75-a5, Arcobacter, and Pasteurella were diminished in SUB samples. Porphyromonas, Peptococcus, Parvimonas, and Campylobacter were diminished in SUP samples, while Tannerella, Proteocalla, Schwartzia, and Neisseria were diminished in SAL samples. Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, and Neisseria were associated with higher oral health scores (worsened health) in plaque samples.

Conclusions: Our results demonstrate the differences that exist among canine salivary, subgingival plaque and supragingival plaque habitats. Salivary samples do not require sedation and are easy to collect, but do not accurately represent the plaque populations that are most important to oral disease. Plaque Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, and Neisseria were associated with higher (worse) oral health scores. Future studies analyzing samples from progressive disease stages are needed to validate these results and understand the role of bacteria in periodontal disease development.

Keywords: 16S rRNA gene; Canine; Oral microbiome; Periodontal disease.

Fig. 1

Bacterial alpha diversity indices of canine salivary and plaque samples as assessed by the observed operational taxonomic units (OTU) (a), Faith’s Phylogenetic Diversity (b), and Shannon Index (c). Groups with different superscripts differ (p<0.001)

Fig. 2

Principal coordinates analysis (PCoA) plots of weighted (a) and unweighted (b) UniFrac distances of oral microbial communities performed on the 97% OTU abundance matrix using QIIME

Fig. 3

Predominant oral bacterial phyla (relative abundance, %) present in plaque (supragingival and subgingival plaque) and saliva samples of healthy adult dogs. ^a-cMeans with different superscripts within phyla differ by Tukey's test (p<0.05). ^w-zMeans with different superscripts within phyla differ by Wilcoxon's test (p<0.05)

Fig. 4

Predominant oral bacterial genera (relative abundance, %) present in plaque (supragingival and subgingival plaque) and saliva samples from healthy adult dogs. ^a-cMeans with different superscripts within a genera differ by Tukey's test (p<0.05). ^w-zMeans with different superscripts within a genera differ by Wilcoxon's test (p<0.05)

Fig. 5

LEfSe results of oral samples identified bacterial phyla enriched in salivary (SAL) and subgingival (SUB) plaque of healthy adult dogs. LDA score ≥ 3

Fig. 6

LEfSe results of oral samples identified bacterial genera enriched in salivary (SAL), subgingival (SUB) plaque, and supragingival (SUP) plaque of healthy adult dogs. LDA score ≥ 3