A cross-sectional survey of bacterial species in plaque from client owned dogs with healthy gingiva, gingivitis or mild periodontitis

Antibacterial characteristics and mechanistic insights of combined tea polyphenols, Nisin, and epsilon-polylysine against feline oral pathogens: a comprehensive transcriptomic and metabolomic analysis

AIMS

This study evaluates the antibacterial characteristics and mechanisms of combined tea polyphenols (TPs), Nisin, and ε-polylysine (PL) against Streptococcus canis, Streptococcus minor, Streptococcus mutans, and Actinomyces oris, common zoonotic pathogens in companion animals.

METHODS AND RESULTS

Pathogenic strains were isolated from feline oral cavities and assessed using minimum inhibitory concentration (MIC) tests, inhibition zone assays, growth kinetics, and biofilm inhibition studies. Among single agents, PL exhibited the lowest MIC values against all four pathogens. TP showed significant resistance against S. minor, and Nisin against S. mutans. The combination treatment (Comb) of TP, Nisin, and PL in a ratio of 13:5:1 demonstrated broad-spectrum antibacterial activity, maintaining low MIC values, forming large inhibition zones, prolonging the bacterial lag phase, reducing growth rates, and inhibiting biofilm formation. RNA sequencing and metabolomic analysis indicated that TP, Nisin, and PL inhibited various membrane-bound carbohydrate-specific transferases through the phosphoenolpyruvate-dependent phosphotransferase system in S. canis, disrupting carbohydrate uptake. They also downregulated glycolysis and the citric acid cycle, inhibiting cellular energy metabolism. Additionally, they modulated the activities of peptidoglycan glycosyltransferases and d-alanyl-d-alanine carboxypeptidase, interfering with peptidoglycan cross-linking and bacterial cell wall stability.

CONCLUSIONS

The Comb therapy significantly enhances antibacterial efficacy by targeting multiple bacterial pathways, offering potential applications in food and pharmaceutical antimicrobials.

Age-correlated changes in the canine oral microbiome

Introduction

Canine oral disease has been associated with significant changes in the oral microbiome rather than the presence or absence of individual species. In addition, most studies focus on a single age group of canines and as of yet, the relationship between canine microbiomes and age is poorly understood.

Methods

This study used a shotgun whole gene sequencing approach in tandem with the Aladdin Bioinformatics platform to profile the microbiomes of 96 companion dogs, with the sourmash-zymo reference database being used to perform taxonomic profiling.

Results

Findings showed significant age correlations among 19 species, including positive correlations among several Porphyromonas species and a negative correlation with C. steedae. Although a significant correlation was found between predicted and actual ages, ElasticNet Regression was unable to successfully predict the ages of younger canines based on their microbiome composition. Both microbiome samples and microbial species were successfully clustered by age group or age correlation, showing that the age-microbiome relationship survives dimensionality reduction. Three distinct clusters of microbial species were found, which were characterized by Porphyromonas, Conchiformibius, and Prevotella genera, respectively.

Discussion

Findings showed that the microbiomes of older dogs resembled those that previous literature attributed to dogs with periodontal disease. This suggests that the process of aging may introduce greater risks for canine oral disease.

The Presence of Bacteremia in 13 Dogs Undergoing Oral Surgery Without the Use of Antibiotic Therapy

This study aimed to assess if transient bacteremia developed from dental scaling, root planing (SRP) and dental extraction(s), if the bacteria originated from oral flora, and if the amount of bacteremia produced would warrant the use of pre-, intra-, or post-operative antibiotic therapy in healthy canine patients. Blood cultures were obtained from 13 healthy dogs with chronic periodontal disease that necessitated the extraction of one tooth or multiple teeth. Patients included did not receive any antibiotic therapy for a minimum of 2 weeks prior to their scheduled procedure and did not receive antibiotic therapy intra- or post-operatively. Blood collection occurred at specific time increments to determine the presence of bacteremia and if clearance of the bacteremia occurred post-procedure. The study found transient bacteremia developed at different time increments throughout the dental procedure. At the time of the final sample collection, no bacterial growth was evident in any of the blood cultures. Results of the blood cultures indicated that only four of 13 dogs had evidence of bacterial growth at any one of the time increments; however, by the final collection, there was no bacterial growth suggesting the transient bacteremia had cleared without the use of systemic antimicrobial therapy. The study findings indicate that systemic antibiotic usage is not warranted for severe periodontal disease where an episode of transient bacteremia is produced from SRP and dental extractions in an otherwise healthy patient.

Species-level characterization of saliva and dental plaque microbiota reveals putative bacterial and functional biomarkers of periodontal diseases in dogs

Periodontal diseases are among the most common bacterial-related pathologies affecting the oral cavity of dogs. Nevertheless, the canine oral ecosystem and its correlations with oral disease development are still far from being fully characterized. In this study, the species-level taxonomic composition of saliva and dental plaque microbiota of 30 healthy dogs was investigated through a shallow shotgun metagenomics approach. The obtained data allowed not only to define the most abundant and prevalent bacterial species of the oral microbiota in healthy dogs, including members of the genera Corynebacterium and Porphyromonas, but also to identify the presence of distinct compositional motifs in the two oral microniches as well as taxonomical differences between dental plaques collected from anterior and posterior teeth. Subsequently, the salivary and dental plaque microbiota of 18 dogs affected by chronic gingival inflammation and 18 dogs with periodontitis were compared to those obtained from the healthy dogs. This analysis allowed the identification of bacterial and metabolic biomarkers correlated with a specific clinical status, including members of the genera Porphyromonas and Fusobacterium as microbial biomarkers of a healthy and diseased oral status, respectively, and genes predicted to encode for metabolites with anti-inflammatory properties as metabolic biomarkers of a healthy status.

Characterization of oral microbiota in 6-8-month-old small breed dogs

BACKGROUND

Periodontitis is the most common oral disease in dogs, and its progression and severity are influenced by risk factors, such as age and body size. Recent studies have assessed the canine oral microbiota in relation to different stages of periodontitis and niches within the oral cavity. However, knowledge of the bacterial composition at different ages and body sizes, especially in puppies, is limited. This study aimed to characterize the oral microbiota in the healthy gingiva of small breed puppies using next-generation sequencing. Additionally, we assessed the impact of dental care practices and the presence of retained deciduous teeth on the oral microbiota.

RESULTS

In this study, plaque samples were collected from the gingival margin of 20 small breed puppies (age, 6.9 ± 0.6 months). The plaque samples were subjected to next-generation sequencing targeting the V3-V4 region of the 16 S rRNA. The microbiota of the plaque samples was composed mostly of gram-negative bacteria, primarily Proteobacteria (54.12%), Bacteroidetes (28.79%), and Fusobacteria (5.11%). Moraxella sp. COT-017, Capnocytophaga cynodegmi COT-254, and Bergeyella zoohelcum COT-186 were abundant in the oral cavity of the puppies. In contrast, Neisseria animaloris were not detected. The high abundance of Pasteurellaceae suggests that this genus is characteristic of the oral microbiota in puppies. Dental care practices and the presence of retained deciduous teeth showed no effects on the oral microbiota.

CONCLUSIONS

In this study, many bacterial species previously reported to be detected in the normal oral cavity of adult dogs were also detected in 6-8-month-old small breed dogs. On the other hand, some bacterial species were not detected at all, while others were detected in high abundance. These data indicate that the oral microbiota of 6-8-month-old small breed dogs is in the process of maturating in to the adult microbiota and may also have characteristics of the small dog oral microbiota.

Conserved signatures of the canine faecal microbiome are associated with metronidazole treatment and recovery

Antibiotic resistance is recognised as one of the biggest global threats to human and animal health. Understanding the influence of antibiotics on the canine microbiome is important to know the potential mid-to-long term effects on dysbiosis and mitigate side-effects such as antibiotic-associated diarrhoea. In this study, metronidazole was prescribed to 22 dogs for suspected giardiasis after exhibiting gastrointestinal symptoms such as diarrhoea and/or vomiting. Faecal samples were collected before, during seven days of treatment, and six months post-cessation. Faecal microbiota was assessed with 16S rRNA sequencing. Shannon diversity was reduced for up to three days after the treatment ended, and an altered community persisted for four to six weeks. All dogs recovered to a similar microbiome composition as pre-treatment. Immediately after receiving metronidazole, an increase in the relative abundance of the genera Lactobacillus, Bifidobacterium, and Enterococcus was observed. This may be due to antibiotic resistance commonly exhibited by these organisms. One-to-two weeks post-cessation, several other genera that were sensitive to the antibiotic recovered in abundances, with taxa belonging to the Erysipelotrichaceae family particularly driving composition change. Many of the bacteria initially reduced were associated with carbohydrate fermentation. This suggests scope exists to explore interventions to augment gastrointestinal health and support the re-establishment of the microbiome.

Evaluation of the antibacterial effect of Epigallocatechin gallate on the major pathogens of canine periodontal disease and therapeutic effects on periodontal disease mice

Background

Periodontal disease (PD) is a prevalent oral affliction in canines, with limited therapeutic options available. The potential transmission of oral bacteria from canines to humans through inter-species contact poses a risk of zoonotic infection. Epigallocatechin gallate (EGCG), the principal catechin in green tea polyphenols, exhibits antibacterial properties effective against human PD. Given the clinical parallels between canine and human PD, this study explores the feasibility of employing EGCG as a therapeutic agent for canine PD.

Methods and results

Initially, a survey and statistical analysis of bacterial infection data related to canine PD in China were conducted. Subsequently, the primary pathogenic bacteria of canine PD were isolated and cultivated, and the in vitro antibacterial efficacy of EGCG was assessed. Furthermore, verify the therapeutic effect of EGCG on a mouse PD model in vivo. The high-throughput 16S rRNA gene sequencing identified Porphyromonas, Fusobacterium, Treponema, Moraxella, and Capnocytophaga as the genera that distinguishing PD from healthy canines' gingival crevicular fluid (GCF) samples in China. The anaerobic culture and drug susceptibility testing isolated a total of 92 clinical strains, representing 22 species, from 72 canine GCF samples, including Porphyromonas gulae, Prevotella intermedia, Porphyromonas macacae, etc. The minimum inhibitory concentration (MIC) ranging of EGCG was from 0.019 to 1.25 mg/mL. Following a 7 days oral mucosal administration of medium-dose EGCG (0.625 mg/mL), the abundance of periodontal microorganisms in PD mice significantly decreased. This intervention ameliorated alveolar bone loss, reducing the average cementoenamel junction to the alveolar bone crest (CEJ-ABC) distance from 0.306 mm ± 0.050 mm to 0.161 mm ± 0.026 mm. Additionally, EGCG (0.3125 mg/mL) markedly down-regulated the expression of inflammatory factor IL-6 in the serum of PD mice.

Conclusion

Our research demonstrates the significant antibacterial effects of EGCG against the prevalent bacterium P. gulae in canine PD. Moreover, EGCG exhibits anti-inflammatory properties and proves effective in addressing bone loss in a PD mouse model. These findings collectively suggest the therapeutic potential of EGCG in the treatment of canine PD. The outcomes of this study contribute valuable data, laying the foundation for further exploration and screening of alternative antibiotic drugs to advance the management of canine PD.

Effects of a novel dental chew on oral health outcomes, halitosis, and microbiota of adult dogs

Halitosis in dogs is an initial indication of periodontitis, highlighting its significance as a vital marker for underlying problems. Moreover, the oral microbial population has a significant influence on periodontal disease. Measuring the oral microbiota may be used in addition to breath odor, dental plaque, and gingivitis scoring to assess the impact of dental chews on oral health. In this study, we aimed to determine the differences in breath odor, oral health outcomes, and oral microbiota of adult dogs consuming a novel dental chew compared with control dogs consuming only a diet. Twelve healthy adult female beagle dogs were used in a crossover design study. Treatments (n = 12/group) included: diet only (control) or the diet + a novel dental chew. Each day, one chew was provided 4 h after mealtime. On days 1, 7, 14, 21, and 27, breath samples were analyzed for total volatile sulfur compound concentrations using a halimeter. On day 0 of each period, teeth were cleaned by a veterinary dentist blinded to treatments. Teeth were scored for plaque, calculus, and gingivitis by the same veterinary dentist on day 28 of each period. After scoring, subgingival and supragingival plaque samples were collected for microbiota analysis using Illumina MiSeq. All data were analyzed using SAS (version 9.4) using the Mixed Models procedure, with P < 0.05 being significant. Overall, the dental chews were well accepted. Dogs consuming the dental chews had lower calculus coverage, thickness, and scores, lower gingivitis scores, and less pocket bleeding than control dogs. Breath volatile sulfur compounds were lower in dogs consuming the dental chews. Bacterial alpha-diversity analysis demonstrated that control dogs had higher bacterial richness than dogs fed dental chews. Bacterial beta-diversity analysis demonstrated that samples clustered based on treatment. In subgingival and supragingival plaque, control dogs had higher relative abundances of potentially pathogenic bacteria (Pelistega, Desulfovibrio, Desulfomicrobium, Fretibacterium, Helcococcus, and Treponema) and lower relative abundances of genera associated with oral health (Neisseria, Actinomyces, and Corynebacterium). Our results suggest that the dental chew tested in this study may aid in reducing periodontal disease risk in dogs by beneficially shifting the microbiota population and inhabiting plaque buildup.

Effective Modalities of Periodontitis Induction in Rat Model

Induction of periodontal disease using the rat model is the preferred model for human periodontal disease studies that are related to gene expression, mechanisms of inflammatory regulation, microbial and host responses, resolution, and the healing process. There are 3 methods that are frequently used to induce periodontal disease, which are: ligature application, oral bacterial inoculation, and the lipopolysaccharide injection technique. In the ligature model, sterile non-absorbable sutures or orthodontic wires are widely used to induce local irritation and bacterial plaque accumulation. Secondly, mono and mixed cultures of periodontal bacteria are inoculated orally by gavage or topical application. Lastly, lipopolysaccharide extracted from pathogenic bacteria can be directly injected into the gingival sulcus to induce inflammation and stimulate osteoclastogenesis and alveolar bone loss. Among these methods, ligature application induces inflammation and alveolar bone resorption more promptly compared to other methods. This review will provide an overview of the main induction methods in experimental periodontal disease, with their advantages and disadvantages.

Longitudinal Analysis of Canine Oral Microbiome Using Whole Genome Sequencing in Aging Companion Dogs

Aged companion dogs have a high prevalence of periodontal disease and canine cognitive dysfunction syndrome (CCDS) and the two disorders are correlated. Similarly, periodontal disease and Alzheimer's Disease are correlated in people. However, little is known about the oral microbiota of aging dogs. The goal of this project was to characterize the longitudinal changes in oral microbiota in aged dogs. Oral swabs were taken from ten senior client-owned dogs on 2-3 occasions spanning 24 months and they underwent whole genome shotgun (WGS) sequencing. Cognitive status was established at each sampling time. A statistically significant increase in alpha diversity for bacterial and fungal species was observed between the first and last study visits. Bacteroidetes and proteobacteria were the most abundant bacterial phyla. Porphyromonas gulae was the most abundant bacterial species (11.6% of total reads). The species Lactobacillus gasseri had a statistically significant increase in relative abundance with age whereas Leptotrichia sp. oral taxon 212 had a statistically significant positive longitudinal association with cognition score. There is an increased fungal and bacterial alpha diversity in aging dogs over time and nearly universal oral dysbiosis. The role of the oral microbiota, particularly Leptotrichia and P. gulae and P. gingivalis, in aging and CCDS warrants further investigation.

Therapeutic effect of aged garlic extract on gingivitis in dogs

Periodontal disease is one of the most common dental health problems in dogs. Clinical studies in humans have shown that aged garlic extract (AGE), which contains stable and water-soluble sulfur-containing bioactive compounds, improves the symptoms of periodontal diseases. Our previous study demonstrated that oral administration of AGE in healthy Beagle dogs at 90 mg/kg/day for 12 weeks had no adverse effects such as hemolytic anemia, which is well known to occur as a result of ingestion of Allium species, including onions and garlic, in dogs. However, the therapeutic potential of AGE in canine periodontal disease remains unclear. Accordingly, we investigated the therapeutic effects of AGE in Beagle dogs with mild gingivitis. Feeding 18 mg/kg/day of AGE for 8 weeks resulted in the improvement of gingival index score, level of volatile sulfur compounds in exhaled air, and enzyme activity of periodontal pathogens without any adverse effects on clinical signs and hematological and serum biochemical parameters. Moreover, AGE increased the concentration of salivary cathelicidin, an antimicrobial peptide that contributes to the oral innate immune response. These results suggest that AGE could be a potential therapeutic agent for canine gingivitis.

Developing diagnostic tools for canine periodontitis: combining molecular techniques and machine learning models

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 (rs =0.805), and two periodontal disease associated taxa, Peptostreptococcaceae XI [G-4] sp. COT-019 (rs=0.902) and Clostridiales sp. COT-028 (rs=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.

Bacterial community associated with gingivitis and periodontitis in dogs

Periodontal disease is a chronic condition characterized by bacterial adhesion, followed by biofilm formation, and subsequently by an inflammatory process that progresses to gingivitis and later to periodontitis. The variations in the oral microbiota have been associated with the progression of this disease. This study evaluated the alteration of the cultivable oral microbiota in dogs with different oral health status. Thirty dogs were selected and divided into three groups: healthy, gingivitis, and periodontitis. The collected oral samples were seeded, and colonies with distinct phenotypic characteristics were isolated and classified using sequencing of the 16S rRNA gene. The DNA sequences were aligned, and a phylogenetic tree was constructed. Simpson's diversity index was calculated, and a dissimilarity matrix based on the Jaccard similarity index was used to plot a principal coordinate analysis. A total of 119 bacteria with different colony morphologies were isolated and classified into 4 phyla, 29 genera, and 45 species based on phylogenetic analysis. The results indicated an increase in bacteria belonging to the Proteobacteria phylum and a less extended decrease in Actinobacteria, Firmicutes, and Bacteroidetes phyla in dogs with periodontal disease (gingivitis and periodontitis) compared to healthy dogs. Representatives of the genera Neisseria sp., Corynebacterium sp., Pasteurella sp., and Moraxella sp. increased through the worsening of the periodontal disease, while Staphylococcus sp. decreased. All groups exhibited moderate to high levels of biodiversity index, and the plotted PCoA show a clear separation in the oral microbiome of dogs with periodontitis compared to dogs with gingivitis and the healthy group.

Prevalence of Entamoeba gingivalis and Trichomonas tenax among patients with periodontal disease attending Dental Clinic, University College Hospital, Ibadan

Background

Periodontal disease is often caused by bacterial plaque. However, there are indications that some infective agents, including parasites, may play important roles in the pathogenesis of the disease.

Aim

This study aimed at assessing the prevalence of gingivitis and periodontitis, as well as the prevalence of Entamoeba gingivalis and Trichomonas tenax, in the oral biofilm of individuals with periodontal diseases using polymerase chain reaction.

Materials and Methods

One hundred and six respondents with periodontal disease participated in the study. All study participants had a full-mouth examination, and dental plaque samples were collected with a sterile curette. Samples were transported to the laboratory in a cold chain and stored frozen till analyzed. DNA was extracted from the samples and amplified using EGO and ENTAM primers for Entamoeba and TGBK primers for T. tenax.

Results

The mean age of respondents was 45 ± 16.3 years, with none using tobacco. The prevalence of gingivitis and periodontitis obtained from this study was 84.9% and 15.1%. The prevalence obtained for Entamoeba and T. tenax was 0.9% each; however, no participant had both parasites. The positive samples were from male participants with moderate gingivitis.

Conclusion

Gingivitis was more prevalent than periodontitis, though with a high preponderance in females. E. gingivalis and T. tenax may not be of etiologic importance in periodontal disease as they occurred sparsely in the studied population.

Influence of Gallic Acid-Containing Mouth Spray on Dental Health and Oral Microbiota of Healthy Dogs: A Pilot Study

The pilot study aimed to investigate the effects of GAMS on oral microbiota in healthy dog subjects. Thirty-eight dogs were recruited and randomly allocated to the placebo (n = 19) and treatment groups (n = 19). The dogs were treated with mouth spray once daily for 42 days. The changes in the gingival index (GI), plaque index (PI), and calculus index (CI) were measured at baseline (day 0) and end of the study (42nd day). The changes in the oral microbial composition of representative dogs (placebo, n = 7; and treatment, n = 7) were also evaluated at baseline and end of the study. Oral microbial composition was assessed by sequencing. The sequences were annotated using the QIIME 2.0^TM. The GI, PI, and CI indexes were reduced after the GAMS usage. The abundance of the commensal bacterial phylum Actinobacteria and Chloroflexi, genera Frederiksenia, and Bergeyella was improved after six weeks of GAMS usage. GAMS reduced the pathogenic bacterial species, including Neisseria sp., Desulfobulbus sp., Capnocytophaga canis, and Corynebacterium mustelae. Moreover, some pathogenic bacterial abundances were increased at the end of the study. All the microbial variations were observed within the group. The inter-group analysis revealed that the changes were unrelated to GAMS usage. Further studies need to be carried out using more experimental subjects to confirm the effectiveness of GAMS. More metagenomic data are required to evidence the GMAS impact on the oral microbiome of healthy dogs.

In vitro evaluation of the antibacterial effect of Brazilian red propolis ethanol extract in the prevention of periodontal disease in dogs

Dental plaque (DP) is found on the surface of teeth and comprises a community of microorganisms that form a structured biofilm. Bacteria present in DP are potential periodontal pathogens when there is an imbalance in the healthy oral environment, and are precursors of periodontal disease (PD). In dogs, the treatments, such as mechanical removal, are difficult and expensive to apply. Therefore, in order to seek new therapeutic alternatives to control dental plaque in dogs, Brazilian red propolis ethanol extract (RPEE) was tested to evaluate its antibacterial effect on bacteria isolated from DP of dogs without PD. DP was collected from the supragingival dental surfaces of 10 dogs. Bacterial isolates of DP were identified by PCR and sequencing of 16S rDNA gene. The RPEE was obtained using the ultrasound ethanol extraction technique, and the chemical composition was obtained by HPLC-DAD and UV-spectrophotometry. In total, 29 different bacteria belonging to five genera were identified. Formononetin, biochanin A, liquiritigenin and daidzein were the major constituents of the RPEE. The cytotoxic effect showed cell viability after 24 h above 50 % at all concentrations evaluated. The minimum inhibitory concentration was between 37.5 and 150.0 µg/mL for all bacterial isolates. The minimal bactericidal concentration was between 150 and 1200 µg/mL for Gram-positive and 300-1200 µg/mL for Gram-negative bacteria. The results are promising and suggest that RPEE has significant antibacterial potential against the bacteria present in the DP of healthy dogs. Although further studies are still needed, the results suggest RPEE might be safely used in the prevention of periodontal disease.

The association between gingivitis and oral spirochetes in young cats and dogs

Although gingivitis frequently occurs in young cats, spirochetes are often found in the early stages of periodontal disease. This study was conducted to determine the association between gingivitis and oral spirochetes in young cats and dogs. The degree of gingivitis was evaluated in a total of 68 cats and 31 dogs under one year of age, and plaques were collected from each carnassial. To detect spirochetes or Porphyromonas gulae in plaque samples, 16S rRNA gene was amplified by polymerase chain reaction (PCR) using specific primers. All data were analyzed using Fisher's exact probability test and odds ratio (OR) with a 95% confidence interval (95% CI). The prevalence of gingivitis was significantly higher in young cats (92.6%) than in young dogs (45.2%). The positive rate of spirochetes by PCR in gingivitis cases was 85.4% in young cats and 15.4% in young dogs, and the positive rate of P. gulae was 66.7% in young cats and 15.4% in young dogs. Both results were significantly higher in young cats than in young dogs. In young cats, spirochetes were significantly associated with gingivitis (OR = 7.95; 95% CI = 1.17, 53.83; P < 0.05), but P. gulae was not (OR = 2.44; 95% CI = 0.38, 15.66; P = 0.23). These results suggest that spirochetes may be associated with the early stages of periodontal disease in cats.

Genomic Medicine in Periodontal Disease: Old Issue, New Insights

Genetic variability is the main cause of phenotypic variation. Some variants may be associated with several diseases and can be used as risk biomarkers, identifying animals with higher susceptibility to develop the pathology. Genomic medicine uses this genetic information for risk calculation, clinical diagnosis and prognosis, allowing the implementation of more effective preventive strategies and/or personalized therapies. Periodontal disease (PD) is the inflammation of the periodontium induced mainly by bacterial plaque and is the leading cause of tooth loss. Microbial factors are responsible for the PD initiation; however, several studies support the genetic influence on the PD progression. The main purpose of the present publication is to highlight the main steps involved in the genomic medicine applied to veterinary patients, describing the flowchart from the characterization of the genetic variants to the identification of potential associations with specific clinical data. After investigating which genes might potentially be implicated in canine PD, the RANK gene, involved in the regulation of osteoclastogenesis, was selected to illustrate this approach. A case-control study was performed using DNA samples from a population of 90 dogs – 50 being healthy and 40 with PD. This analysis allowed for the discovery of four new intronic variations that were banked in GenBank (g.85A>G, g.151G>T, g.268A>G and g.492T>C). The results of this study are not intended to be applied exclusively to PD. On the contrary, this genetic information is intended to be used by other researchers as a foundation for the development of multiple applications in the veterinary clinical field.

Oral Microbiota Populations of Adult Dogs Consuming Wet or Dry Foods

Oral microbiota play a prominent role in canine periodontal disease and wet foods are often blamed for poor oral health, but canine oral microbial communities have been poorly studied. We aimed to determine differences in oral health measures, breath odor, and oral microbiota populations of dogs fed wet or dry food. Twelve adult dogs fed either a commercial dry (extruded) or commercial wet (canned) food for 6 wk were studied. Breath samples were measured for sulfur compounds, teeth were scored for plaque, calculus, and gingivitis by a blinded veterinary dentist, salivary pH was measured, and supragingival (SUP) and subgingival (SUB) plaque samples were collected for microbiota analysis. Plaque DNA was extracted and Illumina sequencing conducted. Phylogenetic data were analyzed using the CosmosID bioinformatics platform and SAS 9.4, with P<0.05 being significant and P<0.10 being trends. Plaque coverage tended to be higher (P<0.10) in dogs fed wet vs. dry food, but other oral health scores were not different. Dogs fed dry food had higher (P<0.05) salivary pH and lower (P<0.05) breath sulfur concentrations than those consuming wet food. Bacterial alpha diversity was higher in SUP than SUB samples, and a clear separation in beta diversity was observed between sample sites on principal coordinates analysis (PCoA) plots. In SUP samples, dogs fed wet food had a higher alpha diversity than dogs fed dry food, with PCoA plots showing a separation between wet and dry food. Relative abundances of Firmicutes, Synergistetes, and 10 bacterial genera were different (P<0.05) in SUB samples of dogs fed wet vs. dry food. Relative abundances of Fusobacteria and over 20 bacterial genera were different (P<0.05) in SUP samples of dogs fed wet vs. dry food. In general, oral health-associated bacterial taxa (Pasteurella, Capnocytophaga, Corynebacterium) were higher, while bacteria associated with poor oral health (Fretibacterium fastidiosum, Filifactor alocis, Treponema medium, Tannerella forsythia, Porphyromonas canoris, Porphyromonas gingivalis) were lower in dogs fed dry food. Such shifts in the oral microbiota may impact periodontal disease risk, but longer dietary intervention studies are required to confirm their role in the disease process. Our results suggest that dogs fed dry extruded foods have lower breath odor and tooth plaque buildup and an oral microbiota population more closely associated with oral health than dogs fed wet canned foods.

Effectiveness of oral care interventions on malodour in dogs

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.

Treponema denticola as a prognostic biomarker for periodontitis in dogs

Periodontal disease is one of the most common disorders in the oral cavity of dogs and humans. Periodontitis, the irreversible periodontal disease, arises progressively from gingivitis, the reversible inflammatory condition caused by dental plaque. Although the etiology of periodontitis has been widely studied in humans, it is still insufficient for the etiological studies on periodontitis in dogs. Many studies have reported that human periodontitis-related bacteria are putative pathogens responsible for periodontitis in dogs. However, most of these studies have focused on the appearance of a specific microbiome, and most of the cohort studies have insufficient sample sizes to generalize their results. In the present study, subgingival samples collected from 336 teeth were categorized into three groups at first, based on clinical outcomes (healthy, gingivitis, periodontitis). Subsequently, the periodontitis samples were further divided into three subgroups (early, moderate, and advanced periodontitis) according to the degree of periodontal attachment loss. Healthy and gingivitis were grouped as a reversible group, and the three subgroups were grouped as an irreversible group. To investigate trends of periodontopathic bacteria in the samples of dogs, a quantitative real-time polymerase chain reaction (PCR) was performed for quantification of 11 human periodontopathic bacteria as follows: Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia, Treponema denticola (Td), Fusobacterium nucleatum, Prevotella nigrescens, Prevotella intermedia, Parvimonas micra, Eubacterium nodatum, Campylobacter rectus, and Eikenella corrodens. The PCR results showed that Aa and Pg, the representative periodontopathic bacteria, were not significantly correlated or associated with the periodontitis cases in dogs. However, interestingly, Td was strongly associated with the irreversible periodontal disease in dogs, in that it was the most prevalent bacterium detected from the dog samples. These findings indicate that the presence and numbers of Td could be used as a prognostic biomarker in predicting the irreversible periodontal disease and the disease severity in dogs.

Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog

This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.

Oral Microbiome in Dogs and Cats: Dysbiosis and the Utility of Antimicrobial Therapy in the Treatment of Periodontal Disease

Advances in gene sequence technology and data analysis have enabled the detection and taxonomic identification of microorganisms in vivo based on their unique RNA or DNA sequences. Standard culture techniques can only detect those organisms that readily grow on artificial media in vitro. Culture-independent technology has been used to provide a more accurate assessment of the richness (total number of species) and diversity (relative abundance of each species) of microorganisms present in a prescribed location. The microbiome has been defined as the genes and genomes of all microbial inhabitants within a defined environment. Microorganisms within a microbiome interact with each other as well as with the host. A microbiome is dynamic and may change over time as conditions within the defined environment become altered. In oral health, neither gingivitis nor periodontitis is present, and the host and microbiome coexist symbiotically without evoking an inflammatory response. The circumstances that cause a shift from immune tolerance to a proinflammatory response remain unknown, and a unified, all-encompassing hypothesis to explain how and why periodontal disease develops has yet to be described. The purpose of this review is to clarify the current understanding of the role played by the oral microbiome in dogs and cats, describe how the microbiome changes in periodontal disease, and offer guidance on the utility of systemic antimicrobial agents in the treatment of periodontitis in companion animals.

Assessment of Changes in the Oral Microbiome That Occur in Dogs with Periodontal Disease

The oral microbiome in dogs is a complex community. Under some circumstances, it contributes to periodontal disease, a prevalent inflammatory disease characterized by a complex interaction between oral microbes and the immune system. Porphyromonas and Tannerella spp. are usually dominant in this disease. How the oral microbiome community is altered in periodontal disease, especially sub-dominant microbial populations is unclear. Moreover, how microbiome functions are altered in this disease has not been studied. In this study, we compared the composition and the predicted functions of the microbiome of the cavity of healthy dogs to those with from periodontal disease. The microbiome of both groups clustered separately, indicating important differences. Periodontal disease resulted in a significant increase in Bacteroidetes and reductions in Actinobacteria and Proteobacteria. Porphyromonas abundance increased 2.7 times in periodontal disease, accompanied by increases in Bacteroides and Fusobacterium. It was predicted that aerobic respiratory processes are decreased in periodontal disease. Enrichment in fermentative processes and anaerobic glycolysis were suggestive of an anaerobic environment, also characterized by higher lipopolysaccharide biosynthesis. This study contributes to a better understanding of how periodontal disease modifies the oral microbiome and makes a prediction of the metabolic pathways that contribute to the inflammatory process observed in periodontal disease.

Study of microbiocenosis of canine dental biofilms

Dental biofilm is a complex microbial community influenced by many exogenous and endogenous factors. Despite long-term studies, its bacterial composition is still not clearly understood. While most of the research on dental biofilms was conducted in humans, much less information is available from companion animals. In this study, we analyzed the composition of canine dental biofilms using both standard cultivation on solid media and amplicon sequencing, and compared the two approaches. The 16S rRNA gene sequences were used to define the bacterial community of canine dental biofilm with both, culture-dependent and culture-independent methods. After DNA extraction from each sample, the V3-V4 region of the 16S rRNA gene was amplified and sequenced via Illumina MiSeq platform. Isolated bacteria were identified using universal primers and Sanger sequencing. Representatives of 18 bacterial genera belonging to 5 phyla were isolated from solid media. Amplicon sequencing largely expanded this information identifying in total 284 operational taxonomic units belonging to 10 bacterial phyla. Amplicon sequencing revealed much higher diversity of bacteria in the canine dental biofilms, when compared to standard cultivation approach. In contrast, cultured representatives of several bacterial families were not identified by amplicon sequencing.

Dogs' Microbiome From Tip to Toe

Microbiota and microbiome, which refers, respectively, to the microorganisms and conjoint of microorganisms and genes are known to live in symbiosis with hosts, being implicated in health and disease. The advancements and cost reduction associated with high-throughput sequencing techniques have allowed expanding the knowledge of microbial communities in several species, including dogs. Throughout their body, dogs harbor distinct microbial communities according to the location (e.g., skin, ear canal, conjunctiva, respiratory tract, genitourinary tract, gut), which have been a target of study mostly in the last couple of years. Although there might be a core microbiota for different body sites, shared by dogs, it is likely influenced by intrinsic factors such as age, breed, and sex, but also by extrinsic factors such as the environment (e.g., lifestyle, urban vs rural), and diet. It starts to become clear that some medical conditions are mediated by alterations in microbiota namely dysbiosis. Moreover, understanding microbial colonization and function can be used to prevent medical conditions, for instance, modulation of gut microbiota of puppies is more effective to ensure a healthy gut than interventions in adults. This paper gathers current knowledge of dogs' microbial communities, exploring their function, implications in the development of diseases, and potential interactions among communities while providing hints for further research.

Influence of the dental topical application of a nisin-biogel in the oral microbiome of dogs: a pilot study

Periodontal disease (PD) is one of the most widespread inflammatory diseases in dogs. This disease is initiated by a polymicrobial biofilm in the teeth surface (dental plaque), leading to a local inflammatory response, with gingivitis and/or several degrees of periodontitis. For instance, the prevention of bacterial dental plaque formation and its removal are essential steps in PD control. Recent research revealed that the antimicrobial peptide nisin incorporated in the delivery system guar gum (biogel) can inhibit and eradicate bacteria from canine dental plaque, being a promising compound for prevention of PD onset in dogs. However, no information is available regarding its effect on the dog’s oral microbiome. In this pilot study, the influence of the nisin-biogel on the diversity of canine oral microbiome was evaluated using next generation sequencing (NGS), aiming to access the viability of nisin-biogel to be used in long-term experiment in dogs. Composite toothbrushing samples of the supragingival plaque from two dogs were collected at three timepoints: T1—before any application of the nisin-biogel to the animals’ teeth surface; T2—one hour after one application of the nisin-biogel; and T3—one hour after a total of three applications of the nisin-biogel, each 48 hours. After that, microbial profiling was performed by NGS of the V3V4 16s rRNA region. After only one application of the nisin-biogel to the oral cavity of dogs, a statistically significant reduction in microbial diversity was observed (T2) as well as a reduction of some bacterial species potentially related with distinct stages of PD, when compared with samples collected before any application (T1). However, after a total of three nisin-biogel applications (T3), a recovery of the microbial diversity was detected. In conclusion, the nisin-biogel may influence the canine oral microbiome. A reduction in some bacterial species potentially related with distinct stages of PD was observed. This pilot study will help to design a controlled in vivo clinical trial to evaluate nisin-biogel effect on dental plaque progression and canine periodontal indices evolution in a long-term application period.

Dental chews positively shift the oral microbiota of adult dogs

Microbiota plays a prominent role in periodontal disease, but the canine oral microbiota and how dental chews may affect these populations have been poorly studied. We aimed to determine the differences in oral microbiota of adult dogs consuming dental chews compared with control dogs consuming only a diet. Twelve adult female beagle dogs (mean age = 5.31 ± 1.08 yr) were used in a replicated 4 × 4 Latin square design consisting of 28-d periods. Treatments (n = 12/group) included: diet only (CT); diet + Bones & Chews Dental Treats (BC; Chewy, Inc., Dania Beach, FL); diet + Dr. Lyon's Grain-Free Dental Treats (DL; Dr. Lyon's, LLC, Dania Beach, FL); and diet + Greenies Dental Treats (GR; Mars Petcare US, Franklin, TN). Each day, one chew was provided 4 h after mealtime. On day 27, breath samples were analyzed for total volatile sulfur compound concentrations using a Halimeter. On day 0 of each period, teeth were cleaned by a veterinary dentist blinded to treatments. Teeth were scored for plaque, calculus, and gingivitis by the same veterinary dentist on day 28 of each period. After scoring, salivary (SAL), subgingival (SUB), and supragingival (SUP) samples were collected for microbiota analysis using Illumina MiSeq. All data were analyzed using SAS (version 9.4) using the Mixed Models procedure, with P < 0.05 considered significant. All dogs consuming chews had lower calculus coverage and thickness, pocket depth and bleeding, plaque thickness, and halitosis compared with CT. In all sites of collection, CT dogs had a higher relative abundance of one or more potentially pathogenic bacteria (Porphyromonas, Anaerovorax, Desulfomicrobium, Tannerella, and Treponema) and lower relative abundance of one or more genera associated with oral health (Neisseria, Corynebacterium, Capnocytophaga, Actinomyces, Lautropia, Bergeyella, and Moraxella) than those fed chews. DL reduced Porphyromonas in SUP and SUB samples. DL and GR reduced Treponema in SUP samples. DL increased Corynebacterium in all sites of collection. BC increased Corynebacterium in SAL samples. DL and GR increased Neisseria in SAL samples. DL increased Actinomyces in the SUB sample. GR increased Actinomyces in SAL samples. Our results suggest that the dental chews tested in this study may aid in reducing periodontal disease risk in dogs by beneficially shifting the microbiota inhabiting plaque and saliva of a dog's oral cavity. These shifts occurred over a short period of time and were correlated with improved oral health scores.

Microbiome analysis of feline odontoclastic resorptive lesion (FORL) and feline oral health

Introduction

Feline odontoclastic resorptive lesion (FORL) is one of the most common and painful oral diseases of the cat. It is characterised by tooth resorption due to destructive activity of odontoclasts. FORL can result in tooth loss. While the aetiology of FORL is not clearly understood, it is thought to be multifactorial and bacteria are likely to play a major role.

Hypothesis

Dysbiosis of the normal feline oral microbiota leads to an alteration in commensal bacteria populations, which results in the development of FORL.

Aim

The purpose of the current study was to determine the composition of the microbiomes associated with feline oral health and FORL.

Methodology

Supragingival plaque was collected from 25 cats with a healthy oral cavity and 40 cats with FORL. DNA was extracted from each sample, the V4 region of the 16S rRNA gene amplified by polymerase chain reaction and amplicons sequenced. Diversity and species richness analyses were performed, principal component analysis was used to explore differences between the oral microbiomes of healthy cats and those with FORL, and linear discriminant analysis effect size was used to assess differences between the groups.

Results

The six most abundant bacterial genera identified were Bergeyella, Capnocytophaga, Lampropedia, Morexella, Porphyromonas and Treponema. Two-step cluster analysis of the data identified two FORL sub-groups (FORL-1, FORL-2). The FORL-2 sub-group was very similar to the healthy group, whilst the FORL-1 sub-group was clearly different from both the FORL-2 sub-group and the healthy groups. In this analysis, Capnocytophaga (P <0.001) and Lampropedia (P <0.01) were found at significantly lower levels and Porphyromonas at a slightly higher level in the FORL-1 sub-group compared to the healthy and FORL-2 sub-groups. Microbial diversity was found to be less in the FORL-1 sub-group than in the healthy group. Lampropedia sp., a phosphate-accumulating oral commensal species, was significantly lower in the FORL-1 sub-group.

Conclusion

The oral microbiota associated with the FORL-1 sub-group is distinct from that found in the healthy group and FORL-2 sub-group. Lampropedia species may influence the local calcium-phosphate ratio, which could be a factor in tooth and bone resorption observed in FORL.

Comparison of subgingival and gingival margin plaque microbiota from dogs with healthy gingiva and early periodontal disease

The purpose of the investigation was to determine whether canine gingival margin (GM) plaque is a reliable surrogate for subgingival (SG) plaque from a microbial community (microbiota) perspective. SG and GM plaque samples were collected from 381 dogs visiting pet hospitals in the USA, China and Thailand. Dogs with clinically healthy gingivae through to early periodontitis were included in the study. The samples were subject to next generation Illumina sequence analysis to allow microbiota comparisons to be made between the two plaque sources. Overall, the SG and GM samples indicated commonality via the majority community that were shared between them; health associations led to the identification of some significant taxa-specific differences. GM microbiota exhibited lower variability and diversity and were shown to reflect a sub-population of those associated with SG plaque. Both plaque niches, however, demonstrated similar changes in microbial signatures with health and early periodontal disease and did not indicate divergent trends. The key, most abundant microbiota of GM plaque strongly reflect those observed with SG plaque across health and early periodontitis. Microbiota in plaque from above the gum line may therefore be employed as a biomarker of oral health. This opens up the potential to use plaque, sampled from conscious dogs, to define oral health status and improve the diagnosis, treatments and interventions for periodontal disease.

Subgingival microbiota of dogs with healthy gingiva or early periodontal disease from different geographical locations

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.

A polymicrobial biofilm model for testing the antimicrobial potential of a nisin-biogel for canine periodontal disease control

BACKGROUND

Periodontal disease (PD) in dogs is prompted by the establishment of a polymicrobial biofilm at the tooth surface and a subsequent host inflammatory response. Several strategies may be used for PD control, including dental hygiene home care procedures, like toothbrushing, special diet and chew toys that reduce dental plaque accumulation, or professional periodontal treatments. Aiming at PD control, a biogel composed by nisin and guar-gum was previously developed. This work aimed to establish an in vitro model mimicking the PD-associated biofilms and to evaluate the nisin-biogel inhibitory activity against this polymicrobial biofilm by determining its Minimum Biofilm Inhibitory (MBIC) and Eradication Concentrations (MBEC). Bacterial species tested included Neisseria zoodegmatis CCUG 52598T, Corynebacterium canis CCUG 58627T, Porphyromonas cangingivalis DSMZ VPB 4874, Peptostreptococcus canis CCUG 57081 and an Enterococcus faecalis isolate belonging to a collection of oral bacteria obtained from dogs with PD. Before establishing the biofilm, coaggregation between species was determined by optical density measurement after 2 and 24 hours. Nisin-biogel MBIC and MBEC values regarding the polymicrobial biofilm were determined using a modified version of the Calgary biofilm pin lid device, after confirming the presence of the five bacterial species by Fluorescent In Situ Hybridization.

RESULTS

Only 40% of the bacterial dual suspensions were able to coaggregate at 2 hours, but all species tested exhibited a coaggregation percentage higher than 30% at 24 hours. It was possible to establish a 48 h polymicrobial biofilm model composed by the five bacterial species selected. This model was used to determine nisin-biogel MBIC (26.39 ± 5.89 µg/mL) and MBEC (62.5 ± 27.73 µg/mL) values.

CONCLUSIONS

Our results showed that the nisin-biogel can inhibit and eradicate PD multispecies biofilms. As this in vitro model mimics an in vivo periodontal polymicrobial biofilm, our results reinforce the potential of the application of nisin-biogel for canine PD control.

A review of the frequency and impact of periodontal disease in dogs

Periodontal disease is a frequent problem seen in veterinary practices. Primary-care veterinary practices, where diagnosis of periodontal disease is predominantly based on visual oral assessment of conscious dogs, report an average prevalence of 9.3 to 18.2% within the dog population. Detailed examinations of anaesthetised dogs report much higher prevalence of between 44 and 100%. The prevalence and severity of periodontitis varies between sizes of dogs, breeds and individuals. The lack of robust evaluation of these variances opens the opportunity for a review of the topic. A literature search was therefore undertaken to determine the frequency and extent (severity and oral location) of periodontal disease in the dog population. Both clinical and retrospective data based surveys of veterinary records, show there is an increased likelihood of developing periodontitis as age increases and with bodyweight decreases. The maxillary and mandibular incisors, fourth premolars and first molars are likely to develop the disease first although in some breeds the canines may also be involved. Poor oral care is a significant risk factor for the development of periodontal disease although diet, behaviour, environment and genetics are also likely to play a role. The information provided in this review can be used by veterinarians to improve the effectiveness of their diagnosis, treatments and interventions by focussing their efforts on the sizes, breeds and individuals most at risk. Given the potential link between periodontal disease and systemic health, veterinarians have the opportunity to positively impact the quality of life of a large number of dogs and therefore their owners.

World Small Animal Veterinary Association Global Dental Guidelines

Dental, oral, and maxillofacial diseases are some of the most common problems in small animal veterinary practice. These conditions create significant pain as well as localized and potentially systemic infection. As such, the World Small Animal Veterinary Association (WSAVA) believes that un- and under treated oral and dental diseases pose a significant animal welfare concern. Dentistry is an area of veterinary medicine which is still widely ignored and is subject to many myths and misconceptions. Effective teaching of veterinary dentistry in the veterinary school is the key to progression in this field of veterinary medicine, and to the improvement of welfare for all our patients globally. These guidelines were developed to provide veterinarians with the information required to understand best practices for dental therapy and create realistic minimum standards of care. Using the three-tiered continuing education system of WSAVA, the guidelines make global equipment and therapeutic recommendations and highlight the anaesthetic and welfare requirements for small animal patients. This document contains information on common oral and dental pathologies, diagnostic procedures (an easily implementable and repeatable scoring system for dental health, dental radiography and radiology) and treatments (periodontal therapy, extractions). Further, there are sections on anaesthesia and pain management for dental procedures, home dental care, nutritional information, and recommendations on the role of the universities in improving veterinary dentistry. A discussion of the deleterious effects of anaesthesia free dentistry (AFD) is included, as this procedure is ineffective at best and damaging at worst. Throughout the document the negative effects of undiagnosed and/or treated dental disease on the health and well-being of our patients, and how this equates to an animal welfare issue, is discussed.

The Effects of Nutrition on the Gastrointestinal Microbiome of Cats and Dogs: Impact on Health and Disease

The gastrointestinal (GI) microbiome of cats and dogs is increasingly recognized as a metabolically active organ inextricably linked to pet health. Food serves as a substrate for the GI microbiome of cats and dogs and plays a significant role in defining the composition and metabolism of the GI microbiome. The microbiome, in turn, facilitates the host's nutrient digestion and the production of postbiotics, which are bacterially derived compounds that can influence pet health. Consequently, pet owners have a role in shaping the microbiome of cats and dogs through the food they choose to provide. Yet, a clear understanding of the impact these food choices have on the microbiome, and thus on the overall health of the pet, is lacking. Pet foods are formulated to contain the typical nutritional building blocks of carbohydrates, proteins, and fats, but increasingly include microbiome-targeted ingredients, such as prebiotics and probiotics. Each of these categories, as well as their relative proportions in food, can affect the composition and/or function of the microbiome. Accumulating evidence suggests that dietary components may impact not only GI disease, but also allergies, oral health, weight management, diabetes, and kidney disease through changes in the GI microbiome. Until recently, the focus of microbiome research was to characterize alterations in microbiome composition in disease states, while less research effort has been devoted to understanding how changes in nutrition can influence pet health by modifying the microbiome function. This review summarizes the impact of pet food nutritional components on the composition and function of the microbiome and examines evidence for the role of nutrition in impacting host health through the microbiome in a variety of disease states. Understanding how nutrition can modulate GI microbiome composition and function may reveal new avenues for enhancing the health and resilience of cats and dogs.

Effect of feeding a daily oral care chew on the composition of plaque microbiota in dogs

The objective of this study was to investigate the influence of daily feeding of an oral care chew on the composition of canine supragingival plaque microbiota. Twelve beagle dogs were recruited to the randomized cross-over study. The dogs were fed one of two dietary regimes, both consisting of a commercially available wet and dry diet mix, either with or without daily supplementation with an oral care chew. After each 28-day test phase, supragingival plaque samples were collected and processed via Illumina sequencing to determine the microbiota composition. A comparative analysis of bacterial species associated with health and periodontal disease, identified from prior clinical studies, revealed differences between the dietary regimes. Consumption of the daily oral care chew, resulted in a significant increase in proportion of 6 health associated taxa but only 3 disease associated taxa compared to no chew. In contrast, 8 disease and 1 health associated taxa showed increased proportions for no chew versus the oral care chew. Daily feeding of the oral care chew tested in this study has therefore been shown to increase the proportion of health associated bacteria, over bacteria associated with periodontal disease, in supragingival plaque compared to no chew. By influencing plaque microbiota towards a bias for health associated bacteria, feeding of the oral care chew provides a means to reduce the prevalence of bacterial species shown to be associated with periodontal disease in dogs.

The canine oral microbiome: variation in bacterial populations across different niches

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.

Antibacterial effects of sodium tripolyphosphate against Porphyromonas species associated with periodontitis of companion animals

Porphyromonas species are closely associated with companion animal periodontitis which is one of the most common diseases in dogs and cats and leads to serious systemic diseases if left untreated. In this study, we evaluated the antimicrobial effects and mode of action of sodium tripolyphosphate (polyP3, Na₅P₃O₁₀), a food additive with proven safety, using three pathogenic Porphyromonas species. The minimum inhibitory concentrations (MICs) of polyP3 against Porphyromonas gulae, Porphyromonas cansulci, and Porphyromonas cangingivalis were between 500 and 750 mg/L. PolyP3 significantly decreased viable planktonic cells as well as bacterial biofilm formation, even at sub-MIC concentrations. PolyP3 caused bacterial membrane disruption and this effect was most prominent in P. cangingivalis, which was demonstrated by measuring the amount of nucleotide leakage from the cells. To further investigate the mode of action of polyP3, high-throughput whole-transcriptome sequencing was performed using P. gulae. Approximately 30% of the total genes of P. gulae were differentially expressed by polyP3 (> 4-fold, adjusted p value < 0.01). PolyP3 influenced the expression of the P. gulae genes related to the biosynthesis of thiamine, ubiquinone, and peptidoglycan. Collectively, polyP3 has excellent antibacterial effects against pathogenic Porphyromonas species and can be a promising agent to control oral pathogenic bacteria in companion animals.

Endodontic Microbiome of Fractured Non-vital Teeth in Dogs Determined by 16S rRNA Gene Sequencing

Dental fractures resulting in pulp exposure will lead to an endodontic infection with microbes from the oral cavity. However, data on the endodontic microbial composition in veterinary dentistry is lacking. The aim of this study was to examine the microbiome of naturally occurring primary endodontic infections in client-owned dogs. The endodontic microbiome of 10 non-vital teeth with exposed pulp cavities was assessed using a 16S rRNA gene sequencing approach. The results were compared to the microbiome of the subgingival plaque of the same teeth. Analysis revealed an abundant mixed microflora of a comparable richness and diversity and with mostly the same phyla obtained from sulcal and endodontic samples. However, further analysis revealed significant differences between sulcal and endodontic samples in the relative abundance of the most abundant phyla and genera, with the relative abundance of Bacteriodetes being significantly higher in endodontic samples. Although each sample presented a particular profile regarding the genera identified, Bacteroides was the most abundant genus in the endodontic samples. Snowella was also significantly more abundant in endodontic samples, while Porphyromonas and Fusobacterium were significantly more abundant in sulcal samples. We confirmed that the microbiome of the diseased endodontic system is comparably abundant with microorganisms to the healthy subgingival plaque indicating that previous culture-based studies of primary endodontic infections in dogs underestimated the richness and diversity of the endodontic microbiota.

The use of non-rodent model species in microbiota studies

In recent years, tremendous advances have been made in our ability to characterize complex microbial communities such as the gut microbiota, and numerous surveys of the human gut microbiota have identified countless associations between different compositional attributes of the gut microbiota and adverse health conditions. However, most of these findings in humans are purely correlative and animal models are required for prospective evaluation of such changes as causative factors in disease initiation or progression. As in most fields of biomedical research, microbiota-focused studies are predominantly performed in mouse or rat models. Depending on the field of research and experimental question or objective, non-rodent models may be preferable due to better translatability or an inability to use rodents for various reasons. The following review describes the utility and limitations of several non-rodent model species for research on the microbiota and its influence on host physiology and disease. In an effort to balance the breadth of potential model species with the amount of detail provided, four model species are discussed: zebrafish, dogs, pigs, and rabbits.

Genomes from bacteria associated with the canine oral cavity: A test case for automated genome-based taxonomic assignment

Taxonomy for bacterial isolates is commonly assigned via sequence analysis. However, the most common sequence-based approaches (e.g. 16S rRNA gene-based phylogeny or whole genome comparisons) are still labor intensive and subjective to varying degrees. Here we present a set of 33 bacterial genomes, isolated from the canine oral cavity. Taxonomy of these isolates was first assigned by PCR amplification of the 16S rRNA gene, Sanger sequencing, and taxonomy assignment using BLAST. After genome sequencing, taxonomy was revisited through a manual process using a combination of average nucleotide identity (ANI), concatenated marker gene phylogenies, and 16S rRNA gene phylogenies. This taxonomy was then compared to the automated taxonomic assignment given by the recently proposed Genome Taxonomy Database (GTDB). We found the results of all three methods to be similar (25 out of the 33 had matching genera), but the GTDB approach required fewer subjective decisions, and required far less labor. The primary differences in the non-identical taxonomic assignments involved cases where GTDB has proposed taxonomic revisions.

The occurrence of Treponema spp. in gingival plaque from dogs with varying degree of periodontal disease

Periodontal disease is common in dogs and is initiated by gingival plaque composed of several hundred bacterial species. Some of these species have specifically been pointed out as potential periodontal pathogens, such as Treponema spp. Treponema spp. are difficult to culture and therefore the majority have been detected by culture-independent methods, such as PCR (Polymerase Chain Reaction). This leaves many Treponema spp. uncharacterized and unnamed. In this study, treponemes were investigated in gingival plaque from dogs with varying degree of periodontal disease with the aim to describe their occurrence and diversity in dogs. The methods used were culture, phase-contrast microscopy, PCR targeting the 16SrRNA-tRNA^Ile intergenic spacer region (ISR2), sequencing of the ISR2 and phylogenetic analysis. Treponema spp. were detected in samples from 10 out of 11 dogs and isolates were obtained from six dogs. Both healthy and periodontitis affected dogs were Treponema positive. Phylogenetic analysis, based on ISR2 sequences, revealed a large diversity of treponemes in the study population that were found to be distributed mainly in two groups, corresponding to the human oral treponeme phylogroups II (Treponema denticola) and IV (Treponema maltophilum) genetic groups. They were generally more distantly related to other treponemes in these groups. Treponemes from dogs with periodontitis and dogs with mild gingivitis without periodontitis did not differ in any obvious way. The results indicate that several phylotypes of oral treponemes are common in dogs regardless of periodontal status.

Effects of Edible Treats Containing Ascophyllum nodosum on the Oral Health of Dogs: A Double-Blind, Randomized, Placebo-Controlled Single-Center Study

The objective of this placebo-controlled, double-blind, randomized study (designed according to evidence based medicine standards) was to determine the effect of 90-day administration of edible treats containing the brown algae, Ascophyllum nodosum, on plaque and dental calculus accumulation on the teeth of dogs, as well as on other parameters characterizing canine oral health status, including: plaque index (PI), calculus index (CI), oral health index (OHI), gingival bleeding index (GBI), and volatile sulfur compound (VSC) concentration. Sixty client-owned dogs, including Japanese chin, miniature Schnauzer, Chihuahua, Pomeranian, and West Highland White Terrier (WHWT) breeds, underwent professional dental cleaning and were randomly subdivided into two groups receiving daily edible treats containing the brown algae A. nodosum, or placebo, adjusted to their bodyweight. After a comprehensive oral health assessment, including a professional dental cleaning, which were both performed under general anesthesia, clinical assessments of PI, CI, OHI, GBI, and VSC concentration were performed under sedation after 30, 60, and 90 days of treatment. Oral administration of edible treats containing A. nodosum significantly improved PI, CI, and VSC concentration, compared with the placebo-treated group. The consumption of edible treats containing A. nodosum efficiently decreased plaque and calculus accumulation in the investigated dogs. Dogs treated with A. nodosum also exhibited significantly lower concentrations of VSC and better oral health status (e.g., OHI and GBI) than those in the placebo-control group.

Evaluation of the impact of dental prophylaxis on the oral microbiota of dogs

Periodontal disease is one of the most commonly diagnosed oral diseases in dogs and can result from undisturbed dental plaque. Dental prophylaxis is a routinely practiced veterinary procedure, but its effects on both the plaque and oral microbiota is not fully understood. The objectives of this study were to evaluate the impact of dental prophylaxis on the composition of the supragingival plaque and composite oral microbiota in clinically healthy dogs and to determine if composite sampling could be used in lieu of sampling the plaque microbiota directly. Thirty dogs received a dental prophylaxis. Supragingival plaque and composite oral samples were collected just prior to, and one week after dental prophylaxis. A subsample of 10 dogs was followed, and additional samples were collected two and five weeks post-prophylaxis. The V4 region of the 16S rRNA gene was used for Illumina MiSeq next-generation sequencing. Results demonstrate that decreases in Treponema as well as increases in Moraxella and Neisseria distinguished the plaque pre- and one week post-prophylaxis timepoints (all P<0.05). Within the oral microbiota, the initially dominant Psychrobacter (20% relative abundance) disappeared one week later (P<0.0001), and Pseudomonas became the dominant taxon one week after treatment (80% relative abundance, P<0.0001). A rapid transition back towards the pre-dental prophylaxis microbiota by five weeks post-treatment was seen for both niches, suggesting the canine oral microbiota is resilient. Direct comparison of the two environments yielded striking differences, with complete separation of groups. Firmicutes (40%) and Spirochaetes (22%) predominated in the plaque while Proteobacteria (58%) was predominant in the oral microbiota. Greater richness was also seen in the plaque microbiota. This study reveals that prophylaxis had a profound impact on both the plaque and oral microbiota, and the longitudinal results help elucidate the pathophysiology of periodontal disease. The results suggest that oral swabs are a poor proxy for plaque samples and highlight the need to study specific oral niches.

The effect of training interventions on the psychological factors of oral health in pregnant women

Background and aim

Oral health is crucial for high-risk pregnant women in order to preserve their health and the health of their infants. Therefore, this study aimed to determine the impact of training programs on the behavior of pregnant mothers concerning oral health in Khorramabad, Iran.

Methods

This is an educational experimental study carried out in 2015 on 164 pregnant women referring to health centers in the city of Khorramabad who were randomly divided into two groups (each n=82). The instruments for data collection included a questionnaire based on the Health Belief Model regarding oral health and two checklists of oral health indexes (OHIS and DMFT). Data were analyzed using SPSS 20 via paired-samples t-test, independent-samples t-test and Chi-square.

Results

The mean score of knowledge and performance, and the variables of the components of the Health Belief Model including the perceived susceptibility, severity, benefits, barriers and self-efficacy regarding the oral health care, significantly increased in the intervention group following the training intervention (p<0.001). However, the DMFT index did not show any changes after the intervention in the intervention and control groups (p=0.381). On the other hand, the OHIS index significantly decreased in the intervention group as compared with the pre-intervention scores (p=0.002).

Conclusion

The results of this study showed that training based on the Health Belief Model leads to the enhancement of performance regarding oral health in pregnant women and thus prevents any increase in OHIS and DMFT levels during pregnancy.

Molecular-level evaluation of selected periodontal pathogens from subgingival regions in canines and humans with periodontal disease

Dogs commonly serve as a model for various human conditions, including periodontal diseases. The aim of this study was to identify the anaerobic bacteria that colonize the subgingival areas in dogs and humans by using rapid real-time polymerase chain reaction (RT-PCR)-based tests and to compare the results obtained in each species. Bacterial microflora evaluations, both quantitative and qualitative, were performed by applying ready-made tests on twelve dogs and twelve humans. Five samples were collected from each subject's deepest gingival pockets and joined to form a collective sample. The results of the study revealed interspecies similarities in the prevalences of Porphyromonas (P.) gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum. Red complex bacteria comprised the largest portion of the studied bacterial complexes in all study groups, with P. gingivalis being the most commonly isolated bacterium. The results show similarities in the prevalence of bacterial microflora in dogs and humans. Microbiological analysis of gingival pockets by using rapid real-time PCR-based tests in clinical practice, both veterinary and human, can facilitate the choice of appropriate pharmacological treatment and can provide a basis for subsequent verification of the treatment's effectiveness.

Clinical and Histopathologic Characterization of Canine Chronic Ulcerative Stomatitis

Canine chronic ulcerative stomatitis, also known as chronic ulcerative paradental stomatitis, is a painful condition of the oral cavity. The purpose of this study was to determine if there are commonalities in clinical and radiographic features among patients, whether the histopathologic evaluation might inform the pathogenesis, and whether the condition appears similar to human oral mucosal diseases. To do this, we prospectively collected clinical, radiographic, and histopathologic data from 20 dogs diagnosed with the disease. Clinical data were based on a clinical disease activity index, oral and periodontal examination parameters, and full-mouth dental radiographs. The histopathological and immunohistochemical data were based on oral mucosal samples obtained from erosive or ulcerated areas. Our findings revealed that canine chronic stomatitis is clinically characterized by painful oral mucosal ulcers of varying size, pattern, appearance, and distribution, most often associated with teeth with early periodontitis. Histologic examination revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response and an immune-mediated pathogenesis is suspected. The clinical and histopathologic features of this chronic inflammatory mucosal disease in dogs resemble those of oral lichen planus in humans.