Language：English   Publishing type：Research paper (scientific journal)   Publisher：Applied and Environmental Microbiology  

UNLABELLED: Fungi compose a minority but a common component of normal oral microbiota and contribute to oral and systemic health by interacting with bacterial inhabitants. This study investigated the relationship of oral fungal profiles to health status and bacterial profiles of 159 elderly adults receiving community support and home care services. Fungal and bacterial densities and compositions were determined based on the fungal ribosomal internal transcribed spacer region and bacterial 16S rRNA gene amplicon analyses, respectively. The total fungal density of 87 individuals exceeded 5,000 copies, and their microbiota was characterized by significantly less dense bacterial populations and lower relative abundances of oral health-associated taxa, such as Neisseria perflava and Porphyromonas pasteri, compared with those with less than 5,000 copies of fungi. These individuals were significantly older, had fewer teeth, had lower physical function, and comprised more denture users and individuals with cognitive decline. Fungal compositions were classified into three profiles (Candida albicans-dominant, non-albicans Candida-dominant, and non-Candida-dominant), and individuals with a non-albicans Candida-dominant profile exhibited significantly lower physical and cognitive function than those with the Candida albicans-dominant profile. These results demonstrate that a high-density fungal population co-occurs with poor oral and systemic health status of the host and dysbiosis of the bacterial community, and particularly, the overgrowth of non-albicans Candida species may be implicated in worsening systemic conditions. IMPORTANCE: The interaction between fungal and bacterial components involved in the virulence of oral microbiota has received attention. This study demonstrates that an increase in fungal components is associated with a dysbiotic bacterial community and poor health status in elderly adults. Among individuals with a high-density fungal population, particularly, those with a non-albicans Candida-dominant profile had lower physical and cognitive functions than those with a C. albicans-dominant profile. These findings indicate that the evaluation of fungal components, in addition to the bacterial components, is important to understand the involvement of oral microbiota in oral and systemic diseases in elderly adults.

DOI： 10.1128/aem.00857-24

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Language：English   Publisher：Frontiers in Cellular and Infection Microbiology  

The enrichment of oral taxa in the gut has recently been reported as a notable alteration in the microbial balance in patients with intestinal disorders. However, translocation in populations without such diseases remains controversial. In this study, we examined 49 pairs of tongue and rectal samples collected from orthopedic patients without a history of intestinal disorders to verify the presence of oral taxa in the rectal microbiota. The bacterial composition of each sample was determined using 16S rRNA gene sequencing and amplicon sequence variant (ASV) analysis. Although the bacterial compositions of the tongue and rectal microbiota were distinctly different, tongue ASVs were detected in 67.3% of the participants and accounted for 0.0%–9.37% of the rectal microbiota. Particularly, Streptococcus salivarius, Fusobacterium nucleatum, and Streptococcus parasanguinis were abundant in the rectal microbiota. According to the network analysis, tongue taxa, such as S. salivarius and S. parasanguinis, formed a cohabiting group with Klebsiella pneumoniae and Alistipes finegoldii in the rectal microbiota. The total abundance of tongue ASVs in the rectal microbiota was significantly higher in participants with older age, hypertension, and proton pump inhibitor (PPI) use. Our study presents an extensive translocation of oral taxa to the rectum of a population without intestinal disorders and suggests that aging, hypertension, and PPI use are associated with an increased abundance of oral taxa and potential pathogenic bacteria in the rectal microbiota.

DOI： 10.3389/fcimb.2024.1358684

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society for Microbiology  

Acquisition of oral bacteria early in life is considered to have an important role in the establishment of oral microbiota. In this study, we examined tongue swab samples collected from 216 infants at the 18-month checkup, along with samples collected from them and from their mothers at the 4-month checkup. The bacterial composition of each sample was determined using PacBio single-molecule long-read sequencing of the full-length 16S rRNA gene and amplicon sequence variant (ASV) analysis. At 18 months of age, the tongue microbiota was dominated by Streptococcus salivarius, Neisseria perflava, and Granulicatella adiacens; and the overall bacterial composition was more similar to that of the mothers than at 4 months of age. The bacterial composition at 18 months of age was classified into three microbiota profiles: S. salivarius-dominant, Neisseria-dominant, and infant profile dominated by 4 months specific ASVs such as S. salivarius, Streptococcus lactarius, and Streptococcus peroris. Those with infant profiles exhibited significantly higher rates of current breastfeeding, dental caries or white spot lesions, and dental plaque accumulation compared to infants with the other profiles. Comparison between the S. salivarius- and Neisseria-dominant profiles showed that incomplete weaning, low intake of fruits, and frequent intake of sweetened beverages or sweet snacks were significantly associated with the S. salivarius-dominant profile. Our findings, based on a high-resolution profiling approach, demonstrate that the foundation of the adult tongue microbiota is established by 18 months of age, and the bacterial profile is possibly determined by dietary habits during this period.

DOI： 10.1128/mbio.01337-23

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Other Link： https://journals.asm.org/doi/10.1128/mbio.01337-23

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Dental Research  

Ectopic enrichment of oral microbes in the gut is a notable alteration in gut microbial balance. These microbes are likely delivered from the oral cavity with saliva and food; however, evidence of oral-gut microbial transmission is insufficient and needs further investigation. In this observational study, we examined 144 pairs of saliva and stool samples collected from community-dwelling adults to verify the oral-gut microbial link and identify the relevant influencing factors on the increased abundance of oral microbes within the gut. The bacterial composition of each sample was determined using PacBio single-molecule long-read sequencing of the full-length 16S ribosomal RNA gene and amplicon sequence variant (ASV) analysis. Although the bacterial compositions of salivary and gut microbiota were distinctly different, at least 1 ASV was shared between salivary and gut microbiota in 72.9% of subjects. Shared ASVs accounted for 0.0% to 63.1% (median 0.14%) of the gut microbiota in each subject and frequently included abundant Streptococcus salivarius and Streptococcus parasanguinis. Their total relative abundance in the gut was significantly higher in older subjects or those with dental plaque accumulation. The gut microbiota with ≥5% of shared ASVs displayed a higher abundance of Streptococcus, Lactobacillus, and Klebsiella and a lower abundance of Faecalibacterium, Blautia, Megamonas, and Parabacteroides. Our study presents evidence for the translocation of oral bacteria to the gut in community-dwelling adults and suggests that aging and dental plaque accumulation contribute to an increased abundance of oral microbes in the gut, which might be relevant to the compositional shift in the gut commensals.

DOI： 10.1177/00220345231160747

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Clinical Periodontology  

AIM: To evaluate the longitudinal association between yogurt product intake and oral health in a population-based study. MATERIALS AND METHODS: This study included 1967 Japanese residents aged 40-79 years who underwent dental examinations in 2012. Among them, 1469 participants were followed up in 2017 for the incidence of tooth loss, which was defined as two or more teeth lost over 5 years. The intake of yogurt products, defined as yogurt and lactic acid beverages, was estimated using a semi-quantitative food frequency questionnaire. The composition of the salivary microbiota was evaluated. RESULTS: The Poisson regression model showed that a higher intake of yogurt products was negatively associated with the incidence of tooth loss (p for trend = .020), adjusted for potential confounding factors. Mediation analysis confirmed that periodontal condition partly mediated the effect of yogurt product intake on tooth loss, while dental caries experience did not. Additionally, we confirmed the association of a high intake of yogurt products with a low percentage of the salivary microbiota pattern, which was associated with poor oral health. CONCLUSION: These findings suggest that the intake of yogurt products is associated with a lower risk of tooth loss resulting from periodontal disease, probably via modulation of the oral microbiome composition.

DOI： 10.1111/jcpe.13593

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Event date： 2024.11

Language：English   Presentation type：Symposium, workshop panel (nominated)  

Venue：長崎  

Event date： 2024.8

Language：English   Presentation type：Poster presentation  

Venue：札幌  

Event date： 2024.5

Language：English   Presentation type：Poster presentation  

Venue：盛岡  

Event date： 2024.3 - 2024.4

Language：English  

Venue：New Orleans   Country：United States  

Event date： 2023.5

Language：English  

Venue：大阪   Country：Japan  

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