Journal of Oral Microbiology最新文献

Background: The neonatal period is critical for oral microbiome establishment, but temporal patterns in preterm newborns remain unclear. This study examined longitudinal microbiome changes in full-term and preterm newborns and assessed perinatal and clinical influences.

Methods: Oral swabs were collected from 98 newborns (23 full-term, 75 preterm). Samples were obtained at birth and Day 2 for full-term, and at birth, Day 7, and Day 28 for preterm newborns. 16S rRNA gene sequencing was used to analyze microbial diversity, taxonomic shifts, and virulence-related genes.

Results: Preterm newborns showed persistently lower α-diversity and delayed succession compared with full-term newborns. Full-term infants transitioned rapidly from Proteobacteria-dominant to Firmicutes- and Actinobacteria-rich communities, while preterm infants maintained Proteobacteria longer. Diversity in preterm newborns was significantly affected by gestational age, birthweight, delivery mode, feeding type, and β-lactam exposure. Breastfeeding supported more stable diversity, whereas cesarean delivery and formula feeding reduced diversity. Functional profiling revealed greater abundance of virulence-associated genes in preterm newborns, suggesting differences in early host-microbe interactions. .

Conclusions: Preterm newborns exhibit delayed oral microbiome development, influenced by multiple modifiable factors. Supportive strategies, such as breastfeeding and prudent antibiotic use, may help foster microbial stability and potentially reduce infection risk in this vulnerable population.

Objectives: This study aims to explore the mechanisms of the detrimental effects of postmenopausal osteoporosis (PMO) on periodontitis.

Methods: An ovariectomized (OVX) rat model was established to investigate the effects of PMO on alveolar bone homeostasis and periodontal inflammation. Chlorhexidine digluconate (CHX) was administered to rats with OVX - periodontitis to ascertain the involvement of the oral microbiota in the influence of PMO on periodontitis. Finally, oral microbiota transplantation was conducted to examine the oral microbiota's pathogenicity.

Results: OVX rats exhibited increased periodontal trabecular bone resorption and inflammation. In addition, depletion of the oral microbiota by CHX decreased the alveolar bone destruction in OVX - periodontitis rats. Furthermore, 16S rRNA gene sequencing demonstrated that PMO changes the composition of the oral microbiota. Finally, oral microbiota transplantation indicated that PMO enhanced the oral microbiota's pathogenicity.

Conclusion: PMO detrimentally affects periodontitis by increasing periodontal inflammation and the pathogenicity of the oral microbiota, which provides a mechanistic understanding of how PMO affects periodontitis and highlights the necessity of more regular monitoring of the oral microbiota in PMO patients.

Background: Behçet's Disease (BD), a complex autoinflammatory disorder, is increasingly linked to microbial dysbiosis, yet the specific microbial signatures and their functional consequences remain incompletely characterized. Elucidating these alterations is crucial for understanding BD pathogenesis.

Objective: To identify distinct microbial community structures and functional potentials in supragingival plaque microbiomes of BD patients versus healthy controls (HC) using high-resolution shotgun metagenomic sequencing.

Methods: Supragingival plaque from 18 BD patients and 22 HCs was subjected to shotgun metagenomics. Analyses included alpha/beta diversity, taxonomic composition, and MetaCyc pathway abundance, with statistical comparisons.

Results: Despite similar age and clinical attachment levels, BD patients exhibited significantly increased alpha diversity and distinct beta diversity compared to HCs. Differential abundance analysis revealed an enrichment of anaerobic and opportunistic taxa in BD (implicating 4 phyla and 28 genera), alongside 19 significantly altered MetaCyc pathways, indicating substantial functional reprogramming within the BD oral microbiome.

Conclusion: This high-resolution metagenomic analysis reveals profound oral microbiome dysbiosis in Behçet's Disease, characterized by altered diversity, a distinct taxonomic signature enriched with pathobionts, and significant functional shifts. These comprehensive microbial alterations are implicated in contributing to the local and systemic inflammatory processes driving BD pathogenesis, offering potential avenues for diagnostic biomarkers and targeted therapies.

Background: Low-abundance bacterial (LAB) species, despite their low prevalence, may contribute to oral inflammatory diseases by triggering host immune responses. The NLRP3 inflammasome plays a key role in inflammation, but its activation by LAB species remains unclear.

Aim: This study examined whether selected LAB species and their biofilm-secreted components induce cytokine production and inflammasome activation in human peripheral blood mononuclear cells (PBMCs).

Methods: Biofilms of selected LAB species were established, and supernatants were collected. PBMCs were stimulated with biofilms or supernatants, and cytokine levels were quantified using ELISA. The expression of NLRP3 and Caspase-1 genes was analyzed through real-time PCR.

Results: Biofilms induced significantly higher levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, and IL-18) compared to supernatants, with C. hominis, N. flavescens, and D. pneumosintes being the most potent inducers. Biofilms also led to a marked increase in NLRP3 expression, while supernatants primarily activated Caspase-1 expression, indicating distinct inflammasome activation pathways.

Conclusions: These findings highlight the immunostimulatory potential of LAB species, particularly their ability to activate NLRP3 and drive inflammation. The differential activation of NLRP3/Caspase-1 by biofilms and supernatants suggests distinct pathogenic mechanisms. Targeting such mechanisms/pathways could offer new therapeutic strategies to mitigate inflammation linked to oral infections.

Objective: In periodontal research, subgingival biofilm samples are typically collected using sterile paper points and pooled for molecular analyses. Streamlining this process by using a single paper point for molecular analysis could simplify sample collection and allow additional paper points to be used for other investigations. This pilot study evaluated the performance of three commercial DNA extraction kits for analysing small sample volumes (<10 µL).

Methods: Samples were collected from six participants, each contributing 18 paper points from both healthy and periodontitis-affected sites. Bacterial and human DNA yields were quantified using fluorometric measurements combined with qPCR, employing universal 16S primers for bacterial DNA and human-specific GAPDH primers.

Results: Among the tested kits, the DNeasy Blood and Tissue Kit demonstrated the highest efficiency, yielding significantly more total dsDNA in samples from healthy sites compared to both other kits and in samples from periodontitis-affected sites compared to one kit. Bacterial DNA yields were also significantly higher with the DNeasy Kit compared to one of the other kits in both health conditions.

Conclusion: These results suggest that one paper point is sufficient to extract DNA for subsequent bacterial analyses and that the DNeasy Blood and Tissue Kit appears to be the most efficient among the three tested kits.

Backgrounds: Periodontitis-induced alveolar bone loss is a primary cause of tooth loss. Porphyromonas gingivalis (P. gingivalis) is the primary pathogenic bacterium of periodontitis. Outer membrane vesicles (OMVs) derived from P. gingivalis (P.g-OMVs) contain various bioactive molecules, and several studies have suggested that P.g-OMVs may participate in alveolar bone loss caused by periodontitis.

Materials and methods: P.g-OMVs were isolated and characterized. The effect of P.g-OMVs on BMSCs proliferation and osteogenic differentiation was analyzed. High-throughput sequencing, RT-qPCR, and Western blot analysis were performed in BMSCs to unravel the underlying molecular mechanism.

Results: P.g-OMVs promoted proliferation but inhibited osteogenic differentiation of BMSCs. High-throughput sequencing results showed that serum amyloid A (SAA), especially SAA3, was robustly upregulated in P.g-OMVs-treated BMSCs. Upregulated SAA3 promoted TLR4, MyD88, and NF-κB p65 and inhibited osteogenic differentiation of P.g-OMVs-treated BMSCs. The knockdown of SAA3 in BMSCs downregulated P.g-OMVs-induced TLR4, MyD88, and NF-κB p65 and rescued P.g-OMVs-inhibited osteogenic differentiation.

Conclusions: Our results indicate that P.g-OMVs inhibit osteogenic differentiation of BMSCs via the SAA3-mediated TLR4/MyD88/NF-κB axis, providing novel targets for the treatment of periodontitis-induced alveolar bone loss.

Fusobacterium nucleatum, a microorganism ordinarily detected in the oral cavity, is considered as a pathobiont related to periodontitis and a range of human diseases, including colorectal cancer (CRC). The dynamics of how F. nucleatum encourages CRC tumorigenesis and progression has been well-investigated. Recently, mechanisms by which F. nucleatum regulates the tumor immune microenvironment (TiME) and subsequently alters CRC oncogenesis and advancement have drawn more and more attention. The TiME consists of immune cells and non-cellular components like cytokines in the tumor microenvironment. By contacting immune cells in the TiME, F. nucleatum fosters an immunosuppressive TiME, diminishes anti-tumor immunity and promotes CRC development. This also allows F. nucleatum to interfere with immunotherapy process and efficacy. In this review, we present a summary of how F. nucleatum interacts with immune cells within the TiME, thereby promoting CRC progression and influencing CRC immunotherapy effectiveness. This review also integrates insights from molecular pathological epidemiology (MPE) to contextualize host-microbe-environment interactions in CRC. We identify gaps in current knowledge and outline possible future research paths. These findings may offer valuable insights for future mechanistic research and the development of novel therapeutic strategies.

Introduction: Emerging research underscores the gut-brain axis in mental disorder pathophysiology, yet the oral microbiome's contribution to mental health remains underexplored. Elucidating oral microbial signatures in mental and neurological disorders may reveal novel pathobiological mechanisms and advance biomarker discovery for precision diagnostics and microbiota-targeted interventions.

Methods: This systematic review and meta-analysis investigates oral microbiota alterations across 6 different mental disorders, by synthesizing data from 20 case-control studies retrieved from PubMed, Embase, and Cochrane Library. Relative microbial abundance and beta diversity indices were extracted from between-group comparisons. Random-effects meta-analyses were conducted for alpha diversity to characterize microbiota differences between patients and controls.

Results: Key findings included a significantly higher Simpson Index in patients (SMD = 0.42; 95% CI, 0.25 to 0.60) compared to controls. Beta diversity varied significantly only in SZ and MDD. Condition-specific variations in microbial abundance were observed: Rothia enrichment in ASD, overrepresentation of H₂S-producing genera in SZ, and reduced Solobacterium and Leptotrichia in MDD.

Conclusion: Collectively, the meta-analytical synthesis suggests alterations in oral microbiota diversity across mental disorders. Disease-associated microbial shifts highlight the oral microbiome as a candidate factor warranting further investigation for potential diagnostic applications and microbial-targeted therapeutic strategies.

Background: Porphyromonas gingivalis is a keystone pathogen in periodontitis, associated with dysbiosis and chronic inflammation. While its virulence mechanisms are well characterized, its transcriptional heterogeneity at the single-cell level remains unexplored.

Materials and methods: We applied split-pool barcoding-based single-cell RNA sequencing to profile gene expression in 1,942 individual P. gingivalis W83 cells cultured under anaerobic conditions. Clustering and differential expression analyses were conducted to identify distinct transcriptional subpopulations.

Results: We identified six transcriptionally distinct clusters, with the two largest accounting for 72.7% of the population. Minor clusters exhibited signatures related to stress responses, metabolism, membrane transport, and DNA regulation. Sub-clustering of major populations revealed rare subgroups, including one enriched for genes involved in iron acquisition, proteolysis, and transport.

Conclusions: This study presents the first single-cell transcriptomic map of P. gingivalis, revealing rare but functionally significant subpopulations. Such diversity may support bacterial adaptability, virulence, and immune evasion, informing future strategies for targeted periodontal therapy.

Background: This study comparatively evaluated the analytical and diagnostic performance of a multiplex digital polymerase-chain reaction (dPCR) assay and a quantitative real-time PCR (qPCR) for the simultaneous detection and quantification of periodontal pathobionts: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum.

Materials and methods: Subgingival plaque samples from 20 periodontitis patients and 20 periodontally healthy controls were analyzed. Several analytical parameters of the dPCR assay, optimized using DNA standards, were assessed versus qPCR: dynamic range linearity, precision, accuracy, prevalence, sensitivity, specificity, and concordance. The statistical analyses included Mann-Whitney U test, Wilcoxon test, McNemar's test, and Bland-Altman plots.

Results: dPCR showed high linearity (R² > 0.99) and lower intra-assay variability (median CV%: 4.5%) than qPCR (p = 0.020), with comparable accuracy and agreement. dPCR demonstrated superior sensitivity, detecting lower bacterial loads, particularly for P. gingivalis and A. actinomycetemcomitans. The Bland-Altman plots highlighted good agreement at medium/high loads but discrepancies at low concentrations (< 3 log₁₀Geq/mL), resulting in qPCR false negatives and a 5-fold underestimation of the prevalence of A. actinomycetemcomitans in periodontitis patients. High concordance between the assays was observed for F. nucleatum across both study groups.

Conclusions: dPCR outperformed qPCR for quantifying periodontal pathobionts and had superior sensitivity and precision, making it particularly effective in detecting low-level bacterial loads.