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Background: Dental plaque microbes play a key role in the development of periodontal disease. Numerous high-throughput sequencing studies have generated understanding of the bacterial species associated with both canine periodontal health and disease. Opportunities therefore exist to utilise these bacterial biomarkers to improve disease diagnosis in conscious-based veterinary oral health checks. Here, we demonstrate that molecular techniques, specifically quantitative polymerase chain reaction (qPCR) can be utilised for the detection of microbial biomarkers associated with canine periodontal health and disease., Results: Over 40 qPCR assays targeting single microbial species associated with canine periodontal health, gingivitis and early periodontitis were developed and validated. These were used to quantify levels of the respective taxa in canine subgingival plaque samples collected across periodontal health (PD0), gingivitis (PD1) and early periodontitis (PD2). When qPCR outputs were compared to the corresponding high-throughput sequencing data there were strong correlations, including a periodontal health associated taxa, Capnocytophaga sp. COT-339 (r s =0.805), and two periodontal disease associated taxa, Peptostreptococcaceae XI [G-4] sp. COT-019 (r s =0.902) and Clostridiales sp. COT-028 (r s =0.802). The best performing models, from five machine learning approaches applied to the qPCR data for these taxa, estimated 85.7% sensitivity and 27.5% specificity for Capnocytophaga sp. COT-339, 74.3% sensitivity and 67.5% specificity for Peptostreptococcaceae XI [G-4] sp. COT-019, and 60.0% sensitivity and 80.0% specificity for Clostridiales sp. COT-028., Conclusions: A qPCR-based approach is an accurate, sensitive, and cost-effective method for detection of microbial biomarkers associated with periodontal health and disease. Taken together, the correlation between qPCR and high-throughput sequencing outputs, and early accuracy insights, indicate the strategy offers a prospective route to the development of diagnostic tools for canine periodontal disease., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Oral malodour is identified by pet owners as an unpleasant inconvenience, but they may not recognise this likely indicates underlying disease. The primary cause of oral malodour relates to the presence of bacteria in the oral cavity often associated with gingivitis and periodontitis. The purpose of this study was to determine the effect of feeding two oral care chews with different textural properties on oral malodour and the proportion of bacterial species involved in the production of volatile sulphur compounds (VSCs)., Methods: Fourteen dogs (9 Petit Basset Griffon Vendéen (PBGV) and 5 Beagle dogs) participated in the randomised cross-over study for a total of 14 weeks. The cohort was divided into four groups with each exposed to a different intervention per week: chew A, chew B, tooth brushing control or a no intervention control. An induced malodour method was used to assess VSCs in breath samples using a portable gas chromatograph (OralChroma™). Microbiological samples (supragingival plaque and tongue coating scrapes) were analysed for VSC-producing bacteria using Oral Hydrogen Sulfide agar with lead acetate., Results: VSCs were detected in the dogs' breath samples and levels of hydrogen sulphide and methyl mercaptan were found to be reduced following an intervention. Chew B significantly reduced the levels of both hydrogen sulphide (p < 0.001) and methyl mercaptan (p < 0.05) compared to no intervention. Reductions in methyl mercaptan were also observed for chew A and tooth brushing but these were not statistically significant. When compared to no intervention, all interventions significantly reduced the total bacterial load and VSC producing bacterial load in plaque (p < 0.001). For tongue samples, only chew B significantly reduced the total bacterial load and VSC-producing bacterial load (p < 0.001) compared to no intervention., Conclusions: By inducing oral malodour and subsequently applying the one-time interventions, significant reductions in the levels of VSCs were observed. The use of oral care chews texturally designed to deliver a deep, all-round cleaning action can be particularly effective at managing oral malodour in dogs, likely through an enhanced ability to remove bacteria., (© 2022. The Author(s).)

Background: Periodontal disease is the most common oral disease of dogs worldwide and results from a complex interplay between plaque bacteria, the host and environmental factors. Recent studies have enhanced our understanding of the associations between the plaque microbiota and canine periodontal disease. These studies, however, were limited in their geographical reach. Thus associations between the canine oral microbiota and geographical location were investigated by determining the composition of subgingival plaque samples from 587 dogs residing in the United Kingdom (UK), United States of America (USA), China and Thailand using 454-pyrosequencing., Results: After quality filtering 6,944,757 sequence reads were obtained and clustering of these at ≥98% sequence resulted in 280 operational taxonomic units (OTUs) following exclusion of rare OTUs (present at < 0.05% in all four countries). The subgingival plaque from dog populations located in the UK, USA, China and Thailand had a similar composition although the abundance of certain taxa varied significantly among geographical locations. Exploration of the effect of clinical status and age revealed a marked similarity among the bacteria associated with increased age and those associated with gingivitis: Young dogs and those with no gingivitis were dominated by taxa from the phyla Bacteroidetes and Proteobacteria whereas older dogs and those with moderate gingivitis were dominated by members of the Firmicutes. The plaque microbiota of small breed dogs was found to significantly differ to medium and large breeds and was dominated by species belonging to the Firmicutes., Conclusions: The bacterial associations with health, gingivitis and periodontitis were conserved across dogs from the UK, USA, China and Thailand. These bacterial signatures of periodontal health and disease have potential as biomarkers for disease detection.

Background: Microbiota from different niches within the canine oral cavity were profiled and compared. Supragingival plaque and stimulated saliva, were collected alongside samples from the buccal and tongue dorsum mucosa, from 14 Labrador retrievers at three timepoints within a 1 month timeframe. The V3-V4 region of the 16S rRNA gene was sequenced via Illumina MiSeq., Results: Supragingival plaque microbiota had the highest bacterial diversity and the largest number of significant differences in individual taxa when compared to the other oral niches. Stimulated saliva exhibited the highest variability in microbial composition between dogs, yet the lowest bacterial diversity amongst all the niches. Overall, the bacteria of the buccal and tongue dorsum mucosa were most similar., Conclusions: The bacterial community profiles indicated three discrete oral niches: soft tissue surfaces (buccal and tongue dorsum mucosa), hard tissue surface (supragingival plaque) and saliva. The ability to distinguish the niches by their microbiota signature offers the potential for microbial biomarkers to be identified in each unique niche for diagnostic use.

Background: Periodontal disease is the most common oral disease of dogs and has been associated with systemic disease. The purpose of the present study was to determine the extent of periodontal disease in a population of Yorkshire terrier dogs with and without a tooth brushing regimen. Each dog was assessed under general anaesthesia two to five times between 37 and 78 weeks of age. The extent of gingivitis and periodontitis was ascertained for every tooth in the mouth. Gingivitis was measured using time to bleeding on probing, and periodontitis was based on extent of clinical attachment loss (probing depth, gingival recession and furcation exposure)., Results: Of the 49 dogs assessed at 37 weeks of age, 98% had at least one tooth or aspect with early periodontitis (PD2, < 25% attachment loss). The average percentage of teeth with periodontitis in the mouth was 29.6% with 95% confidence interval (23.6, 36.4). The odds of early periodontitis was 2.74 (2.23, 3.37) times higher at 78 weeks of age compared to 37 weeks of age. The canine teeth had a significantly higher probability of periodontitis compared to all other tooth types at both 37 and 78 weeks of age (p < 0.001). In addition, at the same time points, the incisors had a significantly higher probability of periodontitis compared to the molars and premolars (p < 0.001)., Conclusions: Breeds of dog that are susceptible to developing periodontitis, such as Yorkshire terriers, require effective treatments for the prevention of periodontal disease from a young age. Although tooth brushing is one of the most effective methods when it comes to preventative homecare, this is not always realistic, as was found in this study. Therefore alternative ways to retard or prevent plaque accumulation that are practical for both dogs and their owners are required.