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

Characterization of the skin microbiome in normal and cutaneous squamous cell carcinoma affected cats and dogs

Human cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) display microbial dysbiosis with an enrichment of staphylococcal species, which have been implicated in AK and SCC progression. SCCs are common in both felines and canines and are often diagnosed at late stages leading to high disease morbidity and mortality rates. Although recent studies support the involvement of the skin microbiome in AK and SCC progression in humans, there is no knowledge of this in companion animals. Here, we provide microbiome data for SCC in cats and dogs using culture-independent molecular profiling and show a significant decrease in microbial alpha diversity on SCC lesions compared to normal skin (P ≤ 0.05). Similar to human skin cancer, SCC samples had an elevated abundance of staphylococci relative to normal skin-50% (6/12) had >50% staphylococci, as did 16% (4/25) of perilesional samples. Analysis of Staphylococcus at the species level revealed an enrichment of the pathogenic species Staphylococcus felis in cat SCC samples, a higher prevalence of Staphylococcus pseudintermedius in dogs, and a higher abundance of Staphylococcus aureus compared to normal skin in both companion animals. Additionally, a comparison of previously published human SCC and perilesional samples against the present pet samples revealed that Staphylococcus was the most prevalent genera across human and companion animals for both sample types. Similarities between the microbial profile of human and cat/dog SCC lesions should facilitate future skin cancer research.

IMPORTANCE

The progression of precancerous actinic keratosis lesions (AK) to cutaneous squamous cell carcinoma (SCC) is poorly understood in humans and companion animals, despite causing a significant burden of disease. Recent studies have revealed that the microbiota may play a significant role in disease progression. Staphylococcus aureus has been found in high abundance on AK and SCC lesions, where it secretes DNA-damaging toxins, which could potentiate tumorigenesis. Currently, a suitable animal model to investigate this relationship is lacking. Thus, we examined the microbiome of cutaneous SCC in pets, revealing similarities to humans, with increased staphylococci and reduced commensals on SCC lesions and peri-lesional skin compared to normal skin. Two genera that were in abundance in SCC samples have also been found in human oral SCC lesions. These findings suggest the potential suitability of pets as a model for studying microbiome-related skin cancer progression.

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.

Occlusive membranes for guided regeneration of inflamed tissue defects

Guided bone regeneration aided by the application of occlusive membranes is a promising therapy for diverse inflammatory periodontal diseases. Symbiosis, homeostasis between the host microbiome and cells, occurs in the oral environment under normal, but not pathologic, conditions. Here, we develop a symbiotically integrating occlusive membrane by mimicking the tooth enamel growth or multiple nucleation biomineralization processes. We perform human saliva and in vivo canine experiments to confirm that the symbiotically integrating occlusive membrane induces a symbiotic healing environment. Moreover, we show that the membrane exhibits tractability and enzymatic stability, maintaining the healing space during the entire guided bone regeneration therapy period. We apply the symbiotically integrating occlusive membrane to treat inflammatory-challenged cases in vivo, namely, the open and closed healing of canine premolars with severe periodontitis. We find that the membrane promotes symbiosis, prevents negative inflammatory responses, and improves cellular integration. Finally, we show that guided bone regeneration therapy with the symbiotically integrating occlusive membrane achieves fast healing of gingival soft tissue and alveolar bone.

A water additive with pomegranate can reduce dental plaque and calculus accumulation in dogs

Oral homecare plays a major part in dental disease prevention but it can be difficult to perform and time-consuming. Furthermore, the product used can be of limited efficiency. The goal of this study was to assess the efficacy of a water additive to limit the accumulation of plaque and calculus in dogs. Forty dogs were selected and randomly allocated to one of the two groups after scaling and polishing on day 0. The control group received no oral hygiene while the second group received the water additive (Vet Aquadent® FR3SH™, Virbac) every day. After 30 days, plaque and calculus accumulations were evaluated under anesthesia. The Gingival Bleeding Index (GBI) was assessed on days 0 and 30. On day 30, the plaque and calculus indices were significantly smaller (p < 0.05) in the Aquadent group compared to the control group with median (Q1-Q3) scores of 1.22 (0.99-1.44) vs. 2.31 (1.65-3.86), respectively for plaque and 0.25 (0.15-0.42) vs. 0.33 (0.32-0.69) for calculus. Between day 0 and day 30, the GBI significantly decreased in the control group [from 0.39 (0.21-0.56) to 0.19 (0.08-0.29)] and in the Aquadent group [from 0.33 (0.18-0.47) to 0.00 (0.00-0.00)] but the decrease was significantly greater in the Aquadent group. These results show for the first time that the water additive tested can reduce dental deposit accumulation in dogs and improve gingival health. It can be recommended after a dental cleaning, especially to owners who are reluctant to provide dental care at home due to a lack of time or convenience.

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.

Molecular microbiological characteristics of gingival pockets in the periodontal diseases of dogs

Introduction

Canine periodontitis results among other factors from a disturbed balance of dental plaque microflora and an inadequate host inflammatory response to a stimulus. This investigation sought to identify microorganisms associated with canine periodontitis.

Material and Methods

Microbiological analysis was undertaken of gingival pockets in an experimental group of 36 dogs with periodontal diseases. Swabs were collected with the use of Pet Test (MIP Pharma, Berlin, Germany) from patients with gingival pockets deeper than 5 mm. Samples were aggregated and placed in separate shipping containers with the Pet Test kit.

Results

Identification was made of the most common microorganisms, e.g. Porphyromonas gingivalis, Treponema denticola and Prevotella intermedia. The red complex constituted the largest proportion of all analysed organisms (84.26%). Capnocytophaga gingivalis was isolated from 33 dogs, Peptostreptococcus micros from 32 dogs, Fusobacterium nucleatum from 29 animals and P. intermedia from 20.

Conclusion

The highest percentage of pathogens was supplied by P. gingivalis (61%). It is thought that dogs acquire them by means of cross-species transmission. The inter-study variability of results may depend not only on the method of periopathogen detection, but also on environmental factors, host immune status or genetic background. Depending on the state of periodontal disease, patients show varied microbiological profiles of the gingival pockets.

In vitro effectiveness of pomegranate extract present in pet oral hygiene products against canine oral bacterial species

Background and Aim:

Pomegranate is known to possess antibacterial properties, partly because of its punicalagin content. However, its effect on canine oral bacterial species has not yet been elucidated. In this study, we evaluated the effect of pomegranate extract present in pet dental products on the growth and survival of five canine oral bacterial species in biofilms.

Materials and Methods:

Five bacterial species, Neisseria shayeganii, Neisseria canis, Porphyromonas gulae, Porphyromonas macacae, and Porphyromonas crevioricanis, were individually cultured for biofilm formation and exposed to pomegranate extract (or control) for 15 min. Cell survival was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and was compared between different conditions using a student’s t-test. In addition, the individual strains were grown in planktonic suspensions and exposed to serial dilutions of the extract to determine the minimum inhibitory concentration.

Results:

At a concentration of 0.035% w/v, the extract significantly reduced the survival of P. gulae (−39%, p < 0.001) and N. canis (−28%, p = 0.08) in biofilms. At similar concentrations, the extract also completely or partially inhibited the growth of N. canis and Porphyromonas spp. in planktonic suspensions, respectively.

Conclusion:

The pomegranate extract found in some pet dental products can limit bacterial growth and survival in the biofilms formed by N. canis and P. gulae in vitro. As P. gulae is involved in periodontal disease progression, limiting its proliferation using products containing pomegranate extract could contribute to disease prevention. Further studies on dogs receiving such products are necessary to confirm these effects.

The bacteriome of the oral cavity in healthy dogs and dogs with periodontal disease

OBJECTIVE

To compare the bacteriome of the oral cavity in healthy dogs and dogs with various stages of periodontal disease.

ANIMALS

Dogs without periodontal disease (n = 12) or with mild (10), moderate (19), or severe (10) periodontal disease.

PROCEDURES

The maxillary arcade of each dog was sampled with a sterile swab, and swabs were submitted for next-generation DNA sequencing targeting the V1-V3 region of the 16S rRNA gene.

RESULTS

714 bacterial species from 177 families were identified. The 3 most frequently found bacterial species were Actinomyces sp (48/51 samples), Porphyromonas cangingivalis (47/51 samples), and a Campylobacter sp (48/51 samples). The most abundant species were P cangingivalis, Porphyromonas gulae, and an undefined Porphyromonas sp. Porphyromonas cangingivalis and Campylobacter sp were part of the core microbiome shared among the 4 groups, and P gulae, which was significantly enriched in dogs with severe periodontal disease, was part of the core microbiome shared between all groups except dogs without periodontal disease. Christensenellaceae sp, Bacteroidales sp, Family XIII sp, Methanobrevibacter oralis, Peptostreptococcus canis, and Tannerella sp formed a unique core microbiome in dogs with severe periodontal disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Results highlighted that in dogs, potential pathogens can be common members of the oral cavity bacteriome in the absence of disease, and changes in the relative abundance of certain members of the bacteriome can be associated with severity of periodontal disease. Future studies may aim to determine whether these changes are the cause or result of periodontal disease or the host immune response.

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.

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.

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.