The microbiome associated with equine periodontitis and oral health

Equine periodontal disease is a common and painful condition and its severe form, periodontitis, can lead to tooth loss. Its aetiopathogenesis remains poorly understood despite recent increased awareness of this disorder amongst the veterinary profession. Bacteria have been found to be causative agents of the disease in other species, but current understanding of their role in equine periodontitis is extremely limited. The aim of this study was to use high-throughput sequencing to identify the microbiome associated with equine periodontitis and oral health. Subgingival plaque samples from 24 horses with periodontitis and gingival swabs from 24 orally healthy horses were collected. DNA was extracted from samples, the V3–V4 region of the bacterial 16S rRNA gene amplified by PCR and amplicons sequenced using Illumina MiSeq. Data processing was conducted using USEARCH and QIIME. Diversity analyses were performed with PAST v3.02. Linear discriminant analysis effect size (LEfSe) was used to determine differences between the groups. In total, 1308 OTUs were identified and classified into 356 genera or higher taxa. Microbial profiles at health differed significantly from periodontitis, both in their composition (p < 0.0001, F = 12.24; PERMANOVA) and in microbial diversity (p < 0.001; Mann–Whitney test). Samples from healthy horses were less diverse (1.78, SD 0.74; Shannon diversity index) and were dominated by the genera Gemella and Actinobacillus, while the periodontitis group samples showed higher diversity (3.16, SD 0.98) and were dominated by the genera Prevotella and Veillonella. It is concluded that the microbiomes associated with equine oral health and periodontitis are distinct, with the latter displaying greater microbial diversity

The Highly Leukotoxic JP2 Genotype of Aggregatibacter actinomycetemcomitans Is Present in the Population of the West African Island, Sal in Cape Verde : A Pilot Study

Aggregatibacter actinomycetemcomitans is strongly associated with severe periodontitis, possibly due to its production of a potent leukotoxin. A genetic variant, the JP2 genotype, was found to produce more leukotoxin than the wild type because of a mutation in the leukotoxin gene, and this genotype is frequently found in African populations. The aim of this study was to investigate whether this JP2 genotype can be found in a randomly selected group of inhabitants of Sal, Cape Verde. Twenty-nine adults between 20 and 59 years of age (58.6% female) participated, and information on their oral health and living standards was collected. An oral examination was performed for each participant, including DMF-T and CPI scores. Plaque and saliva samples were collected and transported to Europe, where DNA was isolated, and the concentration of A. actinomycetemcomitans and its JP2 genotype was determined using dedicated PCR analyses. All 29 plaque and 31% of the saliva samples harboured A. actinomycetemcomitans, and two participants were positive for the JP2 genotype. The presence of this JP2 genotype was not associated with either CPI or DMF-T. This pilot study is the first to describe the presence of the A. actinomycetemcomitans JP2 genotype in a Cape Verdean population living in the Cape Verde Islands, and the findings warrant further research

Chlorine-based DUWL disinfectant leads to a different microbial composition of water derived biofilms compared to H2O2-based chemical disinfectants in vitro

Background. Biofilm formation in dental unit waterlines (DUWL) may lead to health risks for dental staff and patients. Therefore, dental unit waterlines need to be disinfected, for instance by using chemical disinfectants. However, the application of chemical disinfectants may lead to the selection of specific microorganisms. Therefore, the aim of our study was to assess the microbial composition of water-derived biofilms, after a continuous exposure to maintenance doses of commercially available chemical disinfectants, in vitro. Methods. The AAA-model was used to grow water derived biofilms. The biofilms were subjected to the maintenance dose of each disinfectant. To determine the microbial composition, the V4 hypervariable region of the 16S rRNA gene was sequenced. The sequences were clustered in operational taxonomic units (OTUs). Results. The bacterial composition of biofilms in all treatment groups differed significantly (PERMANOVA F = 4.441, p = 0.001). Pairwise comparisons revealed Anoxyl treated biofilms were significantly different from all groups (p = 0.0001). In the Anoxyl-treated biofilms, the relative abundance of Comamonadaceae and Sphingopyxis was high compared to the Dentosept, Green and Clean and Oxygenal groups. Conclusion. We concluded that exposure to low doses of the chlorine-based chemical disinfectant Anoxyl led to a substantially different composition of water derived biofilms compared to biofilms exposed to H2O2-based chemical disinfectants

Effect of erythritol on microbial ecology of in vitro gingivitis biofilms

Gingivitis is one of the most common oral infections in humans. While sugar alcohols such as erythritol are suggested to have caries-preventive properties, it may also have beneficial effects in prevention of gingivitis by preventing maturation of oral biofilms. The aim of this study was to assess the effect of erythritol on the microbial ecology and the gingivitis phenotype of oral microcosms. Biofilms were inoculated with stimulated saliva from 20 healthy donors and grown in a gingivitis model in the continuous presence of 0 (control group), 5, and 10% erythritol. After 9 days of growth, biofilm formation, protease activity (gingivitis phenotype), and microbial profile analyses were performed. Biofilm growth was significantly reduced in the presence of erythritol, and this effect was dose dependent. Protease activity and the Shannon diversity index of the microbial profiles of the biofilms were significantly lower when erythritol was present. Microbial profile analysis revealed that presence of erythritol induced a compositional shift from periodontitis- and gingivitis-related taxa toward early colonizers. The results of this study suggest that erythritol suppresses maturation of the biofilms toward unhealthy composition. The gingivitis phenotype was suppressed and biofilm formation was reduced in the presence of erythritol. Therefore, it is concluded that erythritol may contribute to a healthy oral ecosystem in vitro

Long-Term Analysis of Resilience of the Oral Microbiome in Allogeneic Stem Cell Transplant Recipients

Stem cell transplantation (SCT) is associated with oral microbial dysbiosis. However, long-term longitudinal data are lacking. Therefore, this study aimed to longitudinally assess the oral microbiome in SCT patients and to determine if changes are associated with oral mucositis and oral chronic graft-versus-host disease. Fifty allogeneic SCT recipients treated in two Dutch university hospitals were prospectively followed, starting at pre-SCT, weekly during hospitalization, and at 3, 6, 12, and 18 months after SCT. Oral rinsing samples were taken, and oral mucositis (WHO score) and oral chronic graft-versus-host disease (NIH score) were assessed. The oral microbiome diversity (Shannon index) and composition significantly changed after SCT and returned to pre-treatment levels from 3 months after SCT. Oral mucositis was associated with a more pronounced decrease in microbial diversity and with several disease-associated genera, such as Mycobacterium, Staphylococcus, and Enterococcus. On the other hand, microbiome diversity and composition were not associated with oral chronic graft-versus-host disease. To conclude, dysbiosis of the oral microbiome occurred directly after SCT but recovered after 3 months. Diversity and composition were related to oral mucositis but not to oral chronic graft-versus-host disease

Long-Term Analysis of Resilience of the Oral Microbiome in Allogeneic Stem Cell Transplant Recipients

Stem cell transplantation (SCT) is associated with oral microbial dysbiosis. However, long-term longitudinal data are lacking. Therefore, this study aimed to longitudinally assess the oral microbiome in SCT patients and to determine if changes are associated with oral mucositis and oral chronic graft-versus-host disease. Fifty allogeneic SCT recipients treated in two Dutch university hospitals were prospectively followed, starting at pre-SCT, weekly during hospitalization, and at 3, 6, 12, and 18 months after SCT. Oral rinsing samples were taken, and oral mucositis (WHO score) and oral chronic graft-versus-host disease (NIH score) were assessed. The oral microbiome diversity (Shannon index) and composition significantly changed after SCT and returned to pre-treatment levels from 3 months after SCT. Oral mucositis was associated with a more pronounced decrease in microbial diversity and with several disease-associated genera, such as Mycobacterium, Staphylococcus, and Enterococcus. On the other hand, microbiome diversity and composition were not associated with oral chronic graft-versus-host disease. To conclude, dysbiosis of the oral microbiome occurred directly after SCT but recovered after 3 months. Diversity and composition were related to oral mucositis but not to oral chronic graft-versus-host disease

Microbial changes in relation to oral mucositis in autologous hematopoietic stem cell transplantation recipients

The aim of this prospective, two center study was to investigate the dynamics of the microbial changes in relation to the development of ulcerative oral mucositis in autologous SCT (autoSCT) recipients. Fifty-one patients were diagnosed with multiple myeloma and treated with high-dose melphalan followed by autoSCT. They were evaluated before, three times weekly during hospitalization, and three months after autoSCT. At each time point an oral rinse was collected and the presence or absence of ulcerative oral mucositis (UOM) was scored (WHO scale). Oral microbiome was determined by using 16S rRNA amplicon sequencing and fungal load by qPCR. Twenty patients (39%) developed UOM. The oral microbiome changed significantly after autoSCT and returned to pre-autoSCT composition after three months. However, changes in microbial diversity and similarity were more pronounced and rapid in patients who developed UOM compared to patients who did not. Already before autoSCT, different taxa discriminated between the 2 groups, suggesting microbially-driven risk factors. Samples with high fungal load (>0.1%) had a significantly different microbial profile from samples without fungi. In conclusion, autoSCT induced significant and reversible changes in the oral microbiome, while patients who did not develop ulcerative oral mucositis had a more resilient microbial ecosystem