Journal of Oral Microbiology最新文献

Background: The COVID-19 pandemic altered societal habits due to social restrictions and health measures implemented during the first half of 2020.

Objective: This study aimed to evaluate the association between oral microbiota composition and age, household cohabitation, SARS-CoV-2 infection, and COVID-19 severity among children and adults under home confinement in Barcelona, Spain.

Design: A prospective study was conducted between April and June 2020 in the Barcelona Metropolitan Area, including children and adults confined during the pandemic. Multiple participants from the same family households were enrolled. Saliva samples were collected from all participants, and oral microbiota composition was characterized using 16S rRNA gene sequencing.

Results: A total of 142 adults and 265 children from 121 households were included. All adults had confirmed SARS-CoV-2 infection, and 20 (14.08%) experienced severe COVID-19. Among children, 58/265 (21.89%) tested positive; all were asymptomatic. In children, oral microbiota diversity and composition did not differ by infection status. In adults, severe COVID-19 was associated with lower diversity and distinct composition compared with mild disease. Marked age-related differences were observed in younger children. Cohabiting individuals shared more amplicon sequence variants than non-cohabitants.

Conclusions: Age and cohabitation strongly influenced oral microbiota composition. In adults, microbiota varied with COVID-19 severity, whereas no differences were observed among asymptomatic children.

Aim: We explored in silico and in vitro the complete bacteriocin profile of the oral probiotic Streptococcus oralis subsp. dentisani strain 7746 with the primary objective of providing a descriptive analysis of bacteriocin genomic organization, regulatory context, and transcriptional expression.

Methods: The recently closed genome of 7746 was subjected to genome mining searches for bacteriocin biosynthetic gene clusters with BAGEL4 and antiSMASH. Orthology conservation analyses were performed to distinguish between bacteriocin-like peptides (Blp) and competence (Com) related peptides. We assessed bacteriocins' transcription by non-quantitative cross-gene RT-PCR.

Results: Three new bacteriocin-coding genes were identified, which increased to 14 the number of bacteriocins encoded by S. dentisani 7746. We proved that all 14 identified bacteriocins are transcriptionally expressed. We have assigned names to bacteriocins with unnamed orthologs in other species, proposing the name Denticins (from Denticin A to Denticin H). Our analysis led us to propose a model for competence and bacteriocin regulation in this strain, ruled by complete sets of Com and Blp-like quorum sensing systems.

Conclusion: Our results suggest that S. dentisani 7746 is the bacterial isolate with the largest repertoire of bacteriocin genes known to date and that part of its blp-like region might have been acquired by horizontal gene transfer from pneumococci.

Background: The oral microbiome has been associated with overall health, but the contribution of dietary habits to oral microbial composition is not well understood.

Objective: We evaluated the association between diet quality (Healthy Eating Index [HEI] 2015) and the oral microbiome in the Agricultural Health Study, NIH-AARP Diet and Health Study, and Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial within 5,546 participants.

Methods: Individual HEI components were scored from FFQ data and summed. Alpha and beta diversity and genus-level presence and relative abundance were estimated. The proportion of variability in the beta diversity matrices explained by diet quality and other covariates were calculated. Linear, logistic, and zero-inflated negative binomial regression models with adjustment for confounders were used and cohort-specific estimates were meta-analyzed.

Results: Age explained the largest variability in beta diversity (Bray-Curtis), followed by smoking, education, and the HEI component for added sugar. Although overall diet quality was not associated with alpha diversity overall, the added sugar component was consistently inversely associated with alpha diversity. At the genus-level, most of the identified associations were with added sugar.

Conclusions: Consumption of added sugars was consistently associated with oral microbial diversity and specific genera.

Background: Pulpitis is a common dental disease driven by complex microbial infections, yet its microbial origins, diversity, and pathogenic mechanisms remain incompletely understood. A major clinical challenge is the absence of objective biological criteria to assess the severity and reversibility of pulpal inflammation, which is essential for decision-making in vital pulp therapy (VPT).

Objective: This review aims to synthesize current evidence on the microbial landscape of pulpitis and to explore microbial- and host-derived biomarkers that may enable objective assessment of inflammation severity and support precision VPT.

Design: We comprehensively reviewed microorganisms implicated in pulpitis and their distinct virulence mechanisms underlying inflammatory responses and tissue damage. Particular emphasis was placed on host responses of dental pulp stem cells (DPSCs) to different microbial infections. Biomarker candidates reported across multiple studies were summarized, and single-cell transcriptomic evidence was integrated to validate microbe-specific DPSC responses.

Results: Distinct microorganisms associated with pulpitis exhibit heterogeneous virulence strategies, inducing diverse inflammatory and degenerative processes within the dental pulp. DPSCs display infection-specific transcriptional responses, revealing molecular signatures linked to inflammation severity and tissue repair potential. Emerging biomarkers derived from both microbial factors and host responses show consistency across studies, with single-cell analyses providing high-resolution validation of these microbe-specific patterns.

Conclusions: Microbial- and host-derived biomarkers hold significant translational potential for stratifying pulpitis severity, informing VPT decision-making, and predicting treatment prognosis. Integrating microbial characterization with host response profiling may advance objective diagnosis and personalized management of pulpitis.

Background: Periodontitis is linked to dyslipidaemia, but the mechanism still requires further investigation.

Objective: This study aimed to investigate the periodontitis-dyslipidaemia interplay, comparing the impact of periodontitis-associated versus healthy salivary microbiota on systemic lipid metabolism in mice via the oral-gut axis.

Design: NHANES analysis established epidemiological link. ApoE-/- mice received salivary microbiota from periodontally healthy (A-PH) or severe periodontitis (A-SP) donors. Serum lipids and gut microbiota were assessed; correlations between microbial shifts and lipid changes were evaluated.

Results: NHANES confirmed significant association between self-reported physician-diagnosed bone loss around teeth and hypercholesterolemia (OR=1.266). A-SP mice exhibited higher TC, LDL and non-HDL compared with A-PH group. Gut dysbiosis featured increased proinflammatory genera (Helicobacter and Prevotella) and reduced beneficial bacteria (Mucispirillum, Parasutterella, and Barnesiella). Prevotella positively correlated with TC, Helicobacter with LDL; beneficial genera negatively correlated with atherogenic lipids.

Conclusions: Collectively, building upon the NHANES link, our findings demonstrate that the salivary microbiome from periodontitis patients, compared to that from healthy individuals, disrupts systemic lipid metabolism and induces gut dysbiosis in mice. The correlation between specific gut microbial shifts and atherogenic lipid profiles provides experimental support for the mediating role of the oral‒gut axis in linking periodontitis to hyperlipidaemia.

Background: Current understanding in arginine metabolism by streptococci is limited in species and strains.

Objectives: We compared the ability of several abundant oral streptococci to synthesize and assimilate arginine.

Design: Multiple species of oral streptococci and their genetic mutants were characterized for growth using synthetic media with specified amounts of arginine and related amino acids. Expression of relevant genes was quantified by RT-qPCR.

Results: An intact arginine deiminase system (ADS) was required for S. sanguinis to grow with little or no arginine, a capacity substantially hindered by oxygen. Importantly, nearly all oral streptococci tested required arginine, ornithine or citrulline for growth, displaying much heterogeneity. S. mutans, while lacking ADS, grew without exogenous arginine; and presence of ornithine significantly affected its growth dynamics with strain-specific outcomes. Furthermore, loss of an ornithine transcarbamylase in S. mutans abolished ornithine-dependent effects and the ability to synthesize arginine. Expression of biosynthetic arg genes in both S. sanguinis and S. mutans was influenced, albeit differentially, by exogenous arginine, ornithine, oxygen, carbohydrates, and integrity of ADS and the major glucose transporter (EII^Man).

Conclusions: Our study suggested that arginine is an essential nutrient for most oral streptococci, excluding S. mutans, and identified ornithine and citrulline as potential metabolic signals in oral microbiome.

Background: Non-communicable diseases (NCDs) involve chronic inflammatory mechanisms to which periodontal periodontal dysbiosis may contribute. The Planetary Health Diet (PHD), a sustainable plant-based model for NCD prevention remains poorly explored regarding its impact on the interdental microbiota.

Objective: To evaluate whether an einkorn-enriched PHD can reduce interdental microbiota dysbiosis and promote oral and general health.

Design: BIOQUALIM was a 3-month, single-arm, uncontrolled longitudinal pilot trial conducted under real-life conditions. Participants reduced their meat consumption by 50% and consumed  ≥100g/day of whole-grain einkorn. Interdental microbiota, periodontal indices, digestive comfort, and quality of life were assessed at baseline, one and three months.

Results: Total bacterial load (p = 0.0236), Tannerella forsythia (p < 0.001) and Treponema denticola (p < 0.001) decreased significantly. Periodontal health improved significantly-probing depth decreased from 1.14 ± 0.70 mm to 0.58 ± 0.51 mm (p < 0.0001) and clinical attachment loss from 1.33 ± 0.73 mm to 0.60 ± 0.57 mm (p < 0.0001). Gingival inflammation decreased by > 60%, and bleeding on probing decreased by >70% (p = 0.0004). Digestive comfort improved- normalized stool frequency (p = 0.0009) and reduced postprandial drowsiness (p = 0.0196). Quality-of-life scores increased significantly (p = 0.039).

Conclusion: An einkorn-enriched PHD was associated with improved interdental microbiota, periodontal health, and well-being, supporting a One Health link between sustainable nutrition, oral microbiota modulation and inflammation-related pathways.

Objectives: Carbohydrate metabolism and subsequent acid production of Candida albicans remain insufficiently understood. C. albicans may utilize xylitol, but its cariogenic implications are understudied. This study examined growth and metabolism of glucose, xylitol and precursor xylose by C. albicans and their effects on glucose metabolism.

Methods: C. albicans JCM1537 was cultured in YNB medium containing 1% glucose, xylose, xylitol or xylose- or xylitol-glucose combinations. Acid production from cells grown on each substrate was assessed by pH-stat system at pH 7.0 using 10 mM substrates. Metabolic end-products were quantified by HPLC and enzymatic methods. Carbon recovery and redox balance of glucose metabolism were calculated stoichiometrically.

Results: Growth and acid production on xylose or xylitol were much lower than on glucose, with no inhibitory effect of xylose or xylitol observed. Glucose carbon was distributed as 50.48% ethanol, 21.95-24.72% bicarbonate, 5.70% glycerol, 2.88% organic acids and 0.12% acetaldehyde, yielding 81.07-84.48% recovery and 93.26-93.97% reduction-oxidation balance.

Conclusions: Although xylose and xylitol did not inhibit C. albicans glucose metabolism, their limited growth and acidogenicity suggest low cariogenic potential. The overall view of glucose metabolism, including high ethanol production, provides new insights into the metabolic impact of C. albicans within the oral microbiome.

Background: Adjunctive therapies have been proposed to enhance periodontal outcomes by modulating the subgingival microbiome. However, the microbiological effects of probiotic supplementation in diabetic patients with periodontitis remain unclear, particularly when assessed using high-resolution sequencing methods.

Aim: To evaluate the effect of a Limosilactobacillus reuteri as an adjunct to subgingival instrumentation on the subgingival microbiome in the treatment of periodontitis in patients with diabetes.

Methods: This was a secondary analysis of a randomized, triple-blind, placebo-controlled clinical trial. Forty patients with stage II-III periodontitis and diabetes received subgingival instrumentation and either L. reuteri lozenges (n = 19) or placebo (n = 21) for 3 months. Subgingival samples were collected at baseline, 3, and 6 months. The V3-V4 region of the 16S rRNA gene was sequenced and analyzed using QIIME2. Alpha diversity was analyzed with mixed-effects models, beta diversity with PERMANOVA, and differential abundance with linear models.

Results: A total of 116 high-quality samples were included. Alpha and beta diversity metrics did not show significant differences between groups or across time points. L. reuteri was detected inconsistently in the subgingival microbiome, with low relative abundances and no sustained presence over time. No bacterial species exhibited significant changes in differential abundance between the probiotic and placebo groups over time.

Conclusions: Adjunctive L. reuteri supplementation did not significantly alter subgingival microbiome diversity or composition over 6 months.