Multilocus sequence typing and phenotypic properties of Streptococcus mutans from Thai children with different caries statuses.

BACKGROUND: Streptococcus mutans is studied for its acidogenic and aciduric characteristics, notably its biofilm formation in the presence of sucrose, toward its role in the caries process. Variations in both genotype and phenotype have been reported among clinical isolates of S. mutans. This study aimed to examine genotypic and phenotypic characteristics of S. mutans obtained from Thai children with varying caries statuses. METHODS: We determined the presence of S. mutans and caries status in 395 children aged 3-4 years. From 325 children carrying S. mutans, we selected 90 with different caries statuses-caries-free (CF; n = 30), low severity of caries (LC; n = 30), or high severity of caries (HC; n = 30). Three isolates of S. mutans were taken from each child, thus, a total of 270 isolates were obtained. Multilocus sequence typing (MLST) was used to genotype the isolates and assess their clonal relationships. The properties, including biofilm formation, collagen binding, and acid production and tolerance were also evaluated. RESULTS: Children with carious lesions showed a higher detection rate and number of S. mutans in saliva than those without caries. S. mutans from individuals with HC status showed the lowest biofilm formation ability, while this group had the highest detection rate of collagen-binding isolates. There was no difference in acid production or tolerance by caries status. Genotyping by MLST did not reveal any clone of S. mutans specific to CF status. This result remained even when we included MLST data from the open-access PubMLST database. MLST did identify clones containing only strains from caries-affected hosts, but tests of their phenotypic properties did not reveal any differences between S. mutans from these clones and clones that were from both caries-free and caries-affected children. CONCLUSIONS: The clonal relationships of S. mutans indicated by MLST were not associated with the status of dental caries in the host.

Genetics causal analysis of oral microbiome on type 2 diabetes in East Asian populations: a bidirectional two-sample Mendelian randomized study.

Introduction: The dysbiosis of the oral microbiome is associated with the progression of various systemic diseases, including diabetes. However, the precise causal relationships remain elusive. This study aims to investigate the potential causal associations between oral microbiome and type 2 diabetes (T2D) using Mendelian randomization (MR) analyses. Methods: We conducted bidirectional two-sample MR analyses to investigate the impact of oral microbiome from saliva and the tongue T2D. This analysis was based on metagenome-genome-wide association studies (mgGWAS) summary statistics of the oral microbiome and a large meta-analysis of GWAS of T2D in East Asian populations. Additionally, we utilized the T2D GWAS summary statistics from the Biobank Japan (BBJ) project for replication. The MR methods employed included Wald ratio, inverse variance weighting (IVW), weighted median, MR-Egger, contamination mixture (ConMix), and robust adjusted profile score (RAPS). Results: Our MR analyses revealed genetic associations between specific bacterial species in the oral microbiome of saliva and tongue with T2D in East Asian populations. The MR results indicated that nine genera were shared by both saliva and tongue. Among these, the genera Aggregatibacter, Pauljensenia, and Prevotella were identified as risk factors for T2D. Conversely, the genera Granulicatella and Haemophilus D were found to be protective elements against T2D. However, different species within the genera Catonella, Lachnoanaerobaculum, Streptococcus, and Saccharimonadaceae TM7x exhibited multifaceted influences; some species were positively correlated with the risk of developing T2D, while others were negatively correlated. Discussion: This study utilized genetic variation tools to confirm the causal effect of specific oral microbiomes on T2D in East Asian populations. These findings provide valuable insights for the treatment and early screening of T2D, potentially informing more targeted and effective therapeutic strategies.

Temporal variation in the oral microbiome and the prediction of early childhood caries in different ethnicities.

Globally, early childhood caries (ECC) is a significant public health concern, necessitating effective prediction and prevention strategies. This study aimed to explore variations in the oral microbiome of saliva from pre-school Han and Uyghur children during ECC development and establish a predictive model based on temporal oral microbiome changes. Saliva samples were collected from a single kindergarten every three months over six months. Forty-four pre-school children provided 132 samples, categorized into six groups: (1) HEF (healthy pre-school Han children), (2) HEO (Han children with caries), (3) HEP (Han children with progressive caries), (4) WEF (healthy pre-school Uyghur children), (5) WEO (Uyghur children with caries), and (6) WEP (Uyghur children with progressive caries). Illumina Miseq sequencing identified oral microbiome differences between groups and time points. The Random Forest (RF) algorithm established ECC prediction models. The T1HEO group exhibited significantly higher Chaol index, observed species index, PD whole tree index, and Shannon index than the T2HEO group (p < 0.01). Similarly, the T1WEO group had significantly higher Chaol index, observed species index, and PD whole tree index than the T2WEO group (p < 0.05). The AUROC value for the ECC prediction model based on temporal oral flora changes was 0.517 (95% CI: 0.275-0.759) for pre-school Han children and 0.896 (95% CI: 0.78-1.00) for pre-school Uyghur children. In the onset of caries in pre-school Han children, bacterial species richness and community diversity in saliva declined, paralleled by a decrease in bacterial species richness in pre-school Uyghur children's oral saliva. The ECC prediction model grounded on temporal oral microflora changes exhibited robust predictive power, particularly for pre-school Uyghur children, potentially leading to more effective ECC prevention measures.

Analysis of Oral Microbiota in Elderly Thai Patients with Alzheimer's Disease and Mild Cognitive Impairment.

Alzheimer's disease (AD) is a neurodegenerative disease that predominantly affects the older adult population. Neuroinflammation may be triggered by the migration of oral microbiota composition changes from the oral cavity to the brain. However, the relationship between oral microbiota composition and neurodegenerative diseases, such as AD, remains poorly understood. Therefore, we conducted a comprehensive comparison of the relative abundance and diversity of bacterial taxa present in saliva among older adults diagnosed with AD, those with mild cognitive impairment (MCI), and healthy controls. Saliva samples and clinical data were collected from 10 AD patients, 46 MCI patients, and 44 healthy older adults. AD patients had lower Clinical Dementia Rating, Montreal Cognitive Assessment, and Mini-mental Status Examination scores, and induced microbial diversity, than the MCI and control groups. Moreover, AD patients exhibited significantly higher levels of Fusobacteriota and Peptostreptococcaceae and lower levels of Veillonella than the MCI and control groups. In conclusion, a high abundance of Fusobacteria at various levels (i.e., phylum, class, family, and genus levels) may serve as a biomarker for AD. The analysis of oral microbiota dysbiosis biomarkers in older adults may be valuable for identifying individuals at risk for AD.

Green Tea Kombucha Impacts Inflammation and Salivary Microbiota in Individuals with Excess Body Weight: A Randomized Controlled Trial.

BACKGROUND: Green tea kombucha (GTK) is a fermented beverage with promising health benefits, but few studies proved its impact on human health. Thus, we aimed to investigate the impact of GTK on weight loss, inflammation, and salivary microbiota in individuals with excess body weight. METHODS: This is a randomized controlled clinical trial that lasted 10 weeks with two groups of individuals with excess body weight: control (CG; n = 29; caloric restriction) and kombucha (KG; n = 30; caloric restriction + 200 mL GTK). Body composition, anthropometry, saliva, and blood collection were performed in the beginning and end of the intervention. Plasma interleukins were determined by flow cytometry. Salivary microbiota was analyzed by 16S rRNA sequencing. RESULTS: Both groups decreased weight, BMI, and body fat (p < 0.001) after the intervention, but there were no differences between groups. The KG reduced lipid accumulation product (LAP) (p = 0.029). Both groups decreased IL-1ß and IL-8, but IL-6 increased in the CG (p = 0.023) compared to the kombucha group. Alpha and beta diversity of salivary microbiota increased in the KG. Moreover, the KG presented lower Bacillota/Bacteroidota ratio (p = 0.028), and BMI was positively associated with the Bacillota phylum. CONCLUSIONS: GTK did not enhance weight loss, but it decreased the LAP. GTK helped in the inflammatory profile and induced positive changes in oral microbiota composition.

Decoding the diagnostic and therapeutic potential of microbiota using pan-body pan-disease microbiomics.

The human microbiome emerges as a promising reservoir for diagnostic markers and therapeutics. Since host-associated microbiomes at various body sites differ and diseases do not occur in isolation, a comprehensive analysis strategy highlighting the full potential of microbiomes should include diverse specimen types and various diseases. To ensure robust data quality and comparability across specimen types and diseases, we employ standardized protocols to generate sequencing data from 1931 prospectively collected specimens, including from saliva, plaque, skin, throat, eye, and stool, with an average sequencing depth of 5.3 gigabases. Collected from 515 patients, these samples yield an average of 3.7 metagenomes per patient. Our results suggest significant microbial variations across diseases and specimen types, including unexpected anatomical sites. We identify 583 unexplored species-level genome bins (SGBs) of which 189 are significantly disease-associated. Of note, the existence of microbial resistance genes in one specimen was indicative of the same resistance genes in other specimens of the same patient. Annotated and previously undescribed SGBs collectively harbor 28,315 potential biosynthetic gene clusters (BGCs), with 1050 significant correlations to diseases. Our combinatorial approach identifies distinct SGBs and BGCs, emphasizing the value of pan-body pan-disease microbiomics as a source for diagnostic and therapeutic strategies.

Oral microbiota: Taxonomic composition and functional profile in caries-free and in caries-affected individuals - A systematic review.

OBJECTIVE: To compare the oral microbiota among caries-free (CF) with caries-affected (CA) individuals, both at taxonomic and at functional levels. DESIGN: This systematic review was conducted following PRISMA guidelines. A structured search was carried out in MEDLINE/PUBMED, Web of Science, EMBASE, LILACS, SciELO, Scopus and Google Scholar databases up to September, 2023. Observational studies, without any restriction on date of publication and using next-generation targeted or untargeted sequencing methods for identification of microbial communities were included. Qualitative synthesis was performed from all included studies. RESULTS: 54 studies were included (43 cross-sectional; 11 cohort) comprising more than 3486 participants (at least 1666 CF and 1820 CA) whose saliva and/or dental plaque were used as clinical samples. Methodological quality was graded as "fair" for most of the studies. The abundance of 87 bacterial and 44 fungal genera were statistically different among CF and CA individuals. Atopobium spp., Capnocytophaga spp., Lactobacillus spp., Prevotella spp., Scardovia spp., Selenomonas spp. among others were frequently reported as being more abundant in CA individuals. Several functional patterns, such as lipids, carbohydrate, starch, sucrose, amino sugar metabolisms, among others, were identified as being specifically related to CF or to CA conditions. CONCLUSION: In spite of the variability among the included studies and of the predominance of qualitative synthesis, groups of microorganisms as well as specific functional profiles coded by the assessed microbiota are differently abundant among caries-affected and caries-free individuals. These results need to be interpreted with caution considering the limitations inherent to each assessed primary study.

Multi-way modelling of oral microbial dynamics and host-microbiome interactions during induced gingivitis.

Gingivitis-the inflammation of the gums-is a reversible stage of periodontal disease. It is caused by dental plaque formation due to poor oral hygiene. However, gingivitis susceptibility involves a complex set of interactions between the oral microbiome, oral metabolome and the host. In this study, we investigated the dynamics of the oral microbiome and its interactions with the salivary metabolome during experimental gingivitis in a cohort of 41 systemically healthy participants. We use Parallel Factor Analysis (PARAFAC), which is a multi-way generalization of Principal Component Analysis (PCA) that can model the variability in the response due to subjects, variables and time. Using the modelled responses, we identified microbial subcommunities with similar dynamics that connect to the magnitude of the gingivitis response. By performing high level integration of the predicted metabolic functions of the microbiome and salivary metabolome, we identified pathways of interest that describe the changing proportions of Gram-positive and Gram-negative microbiota, variation in anaerobic bacteria, biofilm formation and virulence.

Current clinical framework on nitric oxide role in periodontal disease and blood pressure.

OBJECTIVES: In this review, we explored potential associations between NO and its derivatives, nitrite and nitrate, with periodontal and cardiovascular diseases, with special emphasis on the former. By providing a state-of-the-art and integrative understanding of this topic, we aimed to shed light on the potential role of these three nitrogen oxides in the periodontitis-hypertension nexus, identify knowledge gaps, and point out critical aspects of the experimental methodologies. MATERIALS AND METHODS: A comprehensive literature review was conducted on human salivary and plasma concentrations of nitrate and nitrite, and their impact on periodontal and cardiovascular health. RESULTS: A nitrate-rich diet increases nitrate and nitrite levels in saliva and plasma, promoting oral health by favorably altering the oral microbiome. Chlorhexidine (CHX) mouthrinses disrupt the nitrate-nitrite-NO pathway, reducing NO bioavailability, and potentially affecting blood pressure. This is because CHX eliminates nitrate-reducing bacteria, which are essential for NO production. Although endogenous NO production may be insufficient, the nitrate-nitrite-NO pathway plays a critical role in maintaining appropriate endothelial function, which is balanced by the microbiome and dietary nitrate intake. Dietary nitrate supplementation may lead to beneficial changes in the oral microbiome, thereby increasing the NO bioavailability. However, NO bioavailability can be compromised by reactive oxygen species (ROS) and the uncoupling of endothelial nitric oxide synthase (eNOS), leading to further ROS generation and creating a detrimental cycle. Studies on NO and periodontal disease have shown increased nitrite concentrations in patients with periodontal disease, although these studies have some methodological limitations. In terms of blood pressure, literature suggests that CHX mouthrinses may reduce the capacity of nitrate-reducing bacteria, potentially leading to an increase in blood pressure. CONCLUSIONS: Several studies have suggested an association between NO levels and the development of cardiovascular and periodontal diseases. However, the exact mechanisms linking these diseases remains to be fully elucidated. CLINICAL RELEVANCE: Nitric oxide (NO) is a signaling molecule that plays a crucial role in several physiological processes such as vascular homeostasis, inflammation, immune cell activity, and pathologies such as hypertension and periodontitis.

Comparison of the oral microbiota of patients with atherosclerosis and healthy controls by denaturing gradient gel electrophoresis.

Oral infections can activate local and systemic inflammation. The inflammatory response plays a main role in atherosclerosis. several studies have reported a relation between oral pathogen infection and Atherosclerosis. Recently it was indicated that some oral microbiome has a significant role in triggering atherosclerosis. Denaturing Gradient Gel Electrophoresis (DGGE) is an acceptable assay for identification of uncultivable bacteria. Therefore, we compared the bacterial population diversity in the oral microbiota between atherosclerosis patients and healthy people. Oral microbiota profiling was performed for 139 individuals including 89 patients with CAD and 50 healthy individuals. After DNA extracted from saliva, PCR products were examined and evaluated using DGGE assay. We found that significant relationship between the increased risk of atherosclerosis and the presence of Actinomyces oris, Enterococcus faecalis, Bacterium strain sulresv, Bacterium Culaenoe, NC4, NC7, and NC5 in atherosclerosis patients and healthy individuals. There was also a significant relationship between reducing the risk of atherosclerosis in the presence of NC3 and Entreococcus munotii in atherosclerosis patients and healthy individuals.  In conclusion, presence of some oral microbiota increases the risk of atherosclerosis and the presence of some oral microbiota reduces the risk, so the oral microbiota should be further examined to determine its potential as a biomarker for atherosclerosis.

The Mechanisms and Application Value of Postbiotics in Caries Prevention and Management.

Dental caries, one of the most prevalent diseases globally, affects individuals throughout their lifetimes. Recently, researchers have increasingly focused on postbiotics for caries prevention. Postbiotics, comprising inanimate microorganisms and/or their components, confer health benefits to the host. Growing evidence suggests postbiotics' potential anticaries effects. Specifically, numerous postbiotics have demonstrated the ability to inhibit dental caries onset and progression by modulating oral flora microecology and reducing human caries susceptibility. This review elaborates on the current research regarding postbiotics' anticaries effects, highlights some studies' shortcomings, and innovatively proposes that postbiotics could potentially influence tooth development and salivary characteristics through epigenetic modifications. Furthermore, it anticipates postbiotics' future application in personalised caries treatment, given their multifaceted anticaries potential.

Meta-analysis of oral microbiome reveals sex-based diversity in biofilms during periodontitis.

Sex is an often overlooked, yet compulsory, biological variable when performing biomedical research. Periodontitis is a common yet progressively debilitating chronic inflammatory disorder affecting the tissues supporting teeth that ultimately leads to tooth loss if left untreated. The incidence of periodontitis is sex biased, with increased prevalence in males compared with females but with unknown etiology. We performed a sex-specific meta-analysis using publicly available oral microbiome data from different sampling sites of patients with periodontitis and periodontally healthy controls; sex balance was established for each periodontal health condition. Our results show sex-based diversity in oral biofilms of individuals with periodontitis but not in their saliva, with increased abundance of several periodontal pathogens in subgingival plaques from females compared with males. We devised a quantitative measure, uniquely defined as the Microsexome Index (MSI), which indicates that sexual dimorphism in subgingival bacterial composition is a distinct feature of reduced microbial diversity during periodontitis but not under healthy conditions. In addition, we found that smoking exacerbates microsexome diversity in supragingival biofilms, particularly during periodontitis. Taken together, we provide insights regarding sex-based diversity in periodontitis, a disease with multiorgan associations, and provide the rationale for further mechanistic, diagnostic, and therapeutic studies.

Interkingdom biofilm of Streptococcus pyogenes and Candida albicans: establishment of an in vitro model and dose-response validation of antimicrobials.

Although Streptococcus pyogenes and Candida albicans may colonize tonsillar tissues, the interaction between them in mixed biofilms has been poorly explored. This study established an interkingdom biofilm model of S. pyogenes and C. albicans and verified the dose-response validation of antimicrobials. Biofilms were formed on microplates, in the presence or absence of a conditioning layer of human saliva, using Brain Heart Infusion (BHI) broth or artificial saliva (AS) as a culture medium, and with variations in the microorganism inoculation sequence. Biofilms grown in AS showed higher mass than those grown in BHI broth, and an opposite trend was observed for metabolism. The number of S. pyogenes colonies was lower in AS. Amoxicillin and nystatin showed dose-dependent effects. The inoculation of the two species at the same time, without prior exposure to saliva, and using BHI broth would be the model of choice for future studies assessing the effects of antimicrobials on dual S. pyogenes/C. albicans biofilms.

Detection of Mycobacterium tuberculosis complex in saliva by quantitative PCR: A potential alternative specimen for pulmonary tuberculosis diagnosis.

BACKGROUND: Current tuberculosis (TB) diagnostic tests primarily rely on sputum samples, yet many TB patients cannot produce sputum. This study explored whether saliva could be used instead of sputum to diagnose pulmonary TB (PTB). METHOD: The study included 32 patients with confirmed PTB and 30 patients with other respiratory diseases (ORD). Saliva from all study participants was subjected to quantitative (qPCR) assays targeting the IS1081 gene for detection of M. tuberculosis complex DNA. RESULTS: The sensitivity of saliva IS1081 qPCR was 65.6 % (95 % CI 48.4-80.2 %) with positive results for 21/32 PTB cases, while the specificity was 96.7 % (95 % CI 85.9-99.6 %) with negative results for 29/30 participants with ORD. Sensitivity improved to 72.4 % (95 % CI 54.6-86.0 %) when sputum-Xpert was used as the reference standard, while remaining similar at 65.5 % (95 % CI 47.4-80.7 %) when culture was used as the reference standard. In receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for saliva IS1081 qPCR was 82.5 % (95 % CI 71.7-93.3 %). CONCLUSION: Saliva testing offers a promising alternative to sputum for TB diagnosis among confirmed PTB cases. Larger multicenter studies, encompassing diverse clinical TB characteristics, are needed to provide improved estimates of diagnostic sensitivity and specificity.

Mapping the oral resistome: a systematic review.

Studying individual ecological niches within the oral cavity is a logical first step to understanding the distribution of antimicrobial resistance genes (ARGs); however, it is not representative of the whole oral resistome. The aim of our systematic review was to provide a map of the oral resistome by reviewing the composition of individual niches. A total of 580 papers were retrieved from a search of all English language publications investigating the presence of oral ARGs in five electronic databases between January 2015 and August 2023. Fifteen studies [10 PCR and 5 next-generation sequencing (NGS)] were included in this review. The heterogeneity of methods precluded meta-analysis. ARGs are present throughout the oral cavity with 158 unique ARGs identified across 6 locations - supra and sub-gingival biofilm, mucosa, oropharynx, root canal system (RCS) and saliva. The supragingival biofilm had the highest resistome richness, while the RCS had the least. Tetracycline was the dominant antimicrobial resistance (AMR) class found. Three core genes were identified - tet(M), tet(O) and ermB.This review highlights the necessity of NGS studies to comprehensively characterize the oral resistome in its entirety. This is the logical foundation for future 'omics studies to truly understand the scope of the resistome and its contribution to AMR.

Synergistic effects of arginine and fluoride on human dental biofilm control.

OBJECTIVES: The aim of this study was to quantitatively and comprehensively investigate the combined effects of arginine and fluoride on the suppression of pathogenicity using an in situ biofilm model and next-generation sequencing (NGS). METHODS: Using the in situ model, dental biofilms were formed and the viable bacterial counts and arginine activity in the arginine- and fluoride-containing dentifrice and control groups were measured. We also compared their effects on the bacterial microbiota and predictive functional factors in the control, arginine (arg), and arginine + fluoride (argF) groups using NGS analysis. RESULTS: Compared to the control treatment, the use of 8 % arginine and 1450 ppm fluoride toothpaste resulted in significantly high oral NH4+ concentrations without affecting the number of viable bacteria (P < 0.05). NGS analysis revealed that the oral microbiota of the control, arg, and argF groups were significantly different. Heat map analysis of the predicted functional factors revealed that the arg group had different properties from the other groups and activated specific substrate metabolic pathways; contrastingly, argF treatment inhibited the activity of these pathways and prevented an increase in the abundance of bacterial genera that utilize substrates such as sucrose, suggesting the synergistic effect of arginine and fluoride. CONCLUSIONS: This study indicates that the combination of arginine and fluoride has a synergistic effect on the bacterial microbiota and pathogenicity of dental biofilms compared with arginine alone. CLINICAL SIGNIFICANCE: Our findings suggest that the combination of arginine and fluoride could be used as an effective prebiotic and may inhibit the growth of bacteria associated with dental diseases.

Veillonella parvula promotes root caries development through interactions with Streptococcus mutans and Candida albicans.

Root caries is a subtype of dental caries that predominantly impacts older adults. The occurrence and progression of root caries are associated with the homeostasis of dental plaque biofilm, and microbial synergistic and antagonistic interactions in the biofilm play a significant role in maintaining the oral microecological balance. The objective of the current study was to investigate the role of Veillonella parvula in the microbial interactions and the pathogenesis of root caries. The analysis of clinical samples from patients with/without root caries revealed that Veillonella and V. parvula were abundant in the saliva of patients with root caries. More importantly, a significantly increased colonization of V. parvula was observed in root carious lesions. Further in vitro biofilm and animal study showed that V. parvula colonization increased the abundance and virulence of Streptococcus mutans and Candida albicans, leading to the formation of a polymicrobial biofilm with enhanced anti-stress capacity and cariogenicity, consequently exacerbating the severity of carious lesions. Our results indicate the critical role of V. parvula infection in the occurrence of root caries, providing a new insight for the etiological investigation and prevention of root caries.

Mechanisms of oral microflora in Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disease with complex pathogenesis and no effective treatment. Recent studies have shown that dysbiosis of the oral microflora is closely related to the development of PD. The abnormally distributed oral microflora of PD patients cause degenerative damage and necrosis of dopamine neurons by releasing their own components and metabolites, intervening in the oral-gut-brain axis, crossing the biofilm, inducing iron dysregulation, activating inter-microflora interactions, and through the mediation of saliva,ultimately influencing the development of the disease. This article reviews the structure of oral microflora in patients with PD, the mechanism of development of PD caused by oral microflora, and the potential value of targeting oral microflora in developing a new strategy for PD prevention, diagnosis and treatment.

Assessing oral and toothbrush microbial profiles among high-altitude individuals with and without periodontal disease: a case-control study.

BACKGROUND: Periodontitis is the sixth-most common disease worldwide. The oral microbiome composition and its association with Periodontal disease (PD) have been largely explored; however, limited studies have explored the microbial profiles of both oral and toothbrushes in patients with PD. Thus, this study aimed to ascertain the oral and toothbrushes microbial composition in high-altitude populations, hypothesizing that their correlation with periodontal health would differ from those at lower altitudes, potentially indicating links between environmental factors, microbial colonization patterns, and periodontal health in distinct geographic contexts. METHODS: In the present study, we enrolled 35 individuals including 21 healthy and 14 diagnosed with PD from the Lhasa region of Tibet, China. Saliva and toothbrush samples were collected from each participant to assess the association between toothbrush usage and oral microbiome with PD using 16 S rRNA gene-specific V3-V4 regions sequencing. To assess the oral and toothbrush microbiome composition and diversity and its possible link to PD. RESULTS: Significantly higher Alpha diversity (Shannon index) was observed between the PD group and PD toothbrushes (p = 0.00021) and between the PD group and Healthy toothbrushes (p = 0.00041). The predominant species were Proteobacteria, Bacteroidota, Firmicutes, Actinobacteria, and Fusobacteria, with genera Pseudomonas, Veillonella, Neisseria, Acinetobacter, and Haemophilus. In addition, PICRUST2 analysis unveiled 44 significant pathways differentiating the disease and healthy groups, along with 29 pathways showing significant differences between their respective toothbrush microbial profiles. The distinct oral and toothbrush microbial composition among high-altitude populations suggests potential adaptations to the challenges of high-altitude environments. CONCLUSION: This study emphasizes the importance of tailored dental care strategies, accounting for altitude and racial factors, to effectively manage periodontal health in these communities. Further research is warranted to investigate the specific microbial mechanisms and develop targeted interventions for optimizing oral health in populations across varying altitudes.

The profile of oral microbiome in Chinese elderly population associated with aging and systemic health status.

OBJECTIVE: The health of oral cavity is considered as an important indicator of aging. Oral microbiota is highly associated with the oral health, while the variation of oral microbiome in elderly population and characteristic microbes associated with aging remain unclear. SUBJECTS AND METHODS: In this study, 130 elderly subjects were recruited and divided into 3 groups according to their age: Stage I group (65 ≤ years < 70), Stage II group (70 ≤ years < 75), and Stage III group (75 ≤ years < 80). Their physiological indices were analyzed with using Illumina MiSeq platform and the oral microbiome was determined by high-throughput sequencing. RESULTS: Along with aging, the level of fasting blood glucose, systolic pressure and monocytes are significantly increased. No significant difference was detected on the whole structure of the oral microbiome among groups. While using Metastats and Spearman's correlation analysis, specific bacteria were identified as potential age- or health index-related bacterial genera including Fusobacterium, Parvimonas, Porphyromonas, Aminobacter, Collinsella, Clostridium and Acinetobacter. CONCLUSION: Our study revealed that the composition structure of salivary microbiota in elderly population was relatively stable while specific bacteria were correlated with age and health status, which is promising to be served as health indicators of the elderly after further exploration.