Journal of Oral Microbiology最新文献

Background: The oral cavity is a known reservoir of antibiotic resistance genes (ARGs), but little is known about their subgingival distribution across health states and regions.

Objective: This study aimed to characterize and compare the subgingival resistome and mobile genetic elements (MGEs) in healthy subjects (HS) and periodontitis patients (PP) from Belgium, Chile, Peru and Spain.

Design: Subgingival samples pooled from the deepest site of each quadrant of 40 HS and 40 PP were analyzed via shotgun metagenomic sequencing. After human DNA depletion, the microbial composition was assessed with MetaPhlAn 4.0; ARGs were identified using MEGAHIT and AMRFinderPlus; and MGEs with MGEfinder.

Results: ARG richness was significantly higher in PP (mean 3.98) than in HS (2.15). PP from Peru showed more ARGs than HS from Chile and Spain. In total, 28 ARGs were found, conferring resistance to eight antibiotic classes. β-lactam, tetracycline and aminoglycoside resistance were more abundant in PP. Macrolide resistance was lower in Chilean samples than in Peruvian and Spanish ones. Additionally, 99 MGE-associated genes were detected, with 16 differing by diagnosis and 78 by country.

Conclusions: Subgingival resistome profiles vary significantly by periodontal status and geography, underscoring the influence of clinical and regional factors on antimicrobial resistance in the oral microbiome.

Background: We previously demonstrated that Streptococcus mitis exhibits anticancer properties in vitro. Here, we sought to validate these findings in vivo. Because mice from different vendors harbor distinct microbiomes that can influence disease susceptibility and experimental outcomes, we also examined whether vendor-specific oral and gut microbiomes affect oral carcinogenesis and response to S. mitis intervention.

Materials and methods: Oral carcinogenesis was induced using 4-NQO in C57BL/6 mice from Jackson Laboratory and Taconic Biosciences (n = 32 per vendor). Mice were randomized to biweekly oral swabbing with S. mitis or vehicle for 28 weeks. Oral and fecal microbiomes were profiled at baseline and week 8. At week 32, tongues were evaluated for tumor development.

Results: Oral and gut microbiomes differed significantly between vendors. 4-NQO exposure induced marked microbial shifts and partial convergence of microbiome profiles. Jackson mice developed a significantly higher squamous cell carcinoma (SCC) burden. Several microbial taxa were associated with SCC, notably Clostridium, which was enriched in oral and fecal samples from Jackson mice. S. mitis reduced SCC burden in both cohorts and was accompanied by decreased Clostridium abundance.

Conclusions: These data support S. mitis as a potential anticancer agent and underscore the importance of microbiome context in preclinical cancer models.

Background: HIV infection alters host immunity, including the oral environment, leading to microbial imbalance and increased risk of opportunistic infections. Although antiretroviral therapy (ART) improves immune function, its effect on the oral microbiome remains unclear, particularly in Indonesia. This study investigated oral microbiome composition in people living with HIV and its associations with ART status, age, and sex.

Methods: In this cross-sectional study, oral rinse samples from 245 adults (115 HIV-on-ART, 15 HIV-ART-naïve, and 115 HIV-negative controls) were analysed using 16S rRNA gene sequencing. Alpha and beta diversity metrics, differential abundance (ANCOM-BC2), and multivariable associations (PERMANOVA) were assessed.

Results: The oral microbiome differed significantly between HIV-positive groups and controls (PERMANOVA p = 0.001, R² = 1.8%). HIV-ART-naïve individuals exhibited the highest alpha diversity and enrichment of pro-inflammatory genera, including Fusobacterium, Alloprevotella, and Staphylococcus. ART-treated individuals displayed a partial shift toward the control profile but retained persistent depletion of bacteria such as Filifactor and (Eubacterium) saphenum. Multivariate analysis identified HIV status, age, and sex as independent contributors to microbial variation.

Conclusion: HIV infection is associated with a distinct oral dysbiosis characterised by an increase in opportunistic pathogens and reduction in commensal bacteria. HIV-on-ART individuals show a transitional shift towards the HIV-negative oral microbiome profiles. Our findings suggest that biological and/or demographic factors coupled to oral microbiome profiles may facilitate targeted interventions in the personalised management of oral health for individuals living with HIV.

Background: Oral microbiome diversity has been associated with general health. However, its association with long-term outcomes in hypertensive individuals remains unclear.

Objectives: This study aimed to investigate whether oral microbiome diversity is associated with all-cause mortality in hypertensive individuals.

Design: Data from 2,669 hypertensive individuals in the National Health and Nutrition Examination Survey (NHANES, 2009-2012) were analyzed. Oral microbiome diversity was assessed using four alpha-diversity metrics: the Simpson index, Shannon-Weiner index, Faith's Phylogenetic Diversity, and observed amplicon sequence variants (ASVs). Weighted multivariable Cox proportional hazards regression and interaction analyses were conducted.

Results: During a mean follow-up of 8.61 years, 268 all-cause deaths occurred. Higher oral microbiome diversity assessed by the Simpson index (hazard ratio [HR] = 0.38; 95% confidence interval [CI], 0.20-0.75; P _trend < 0.01) and Shannon-Weiner index (HR = 0.47; 95% CI, 0.25-0.88; P _trend < 0.05), was significantly associated with reduction in all-cause mortality risk. A potential interaction between sex and oral microbiome diversity on mortality risk was observed.

Conclusions: Higher oral microbiome diversity is an independent protective factor for survival in patients with hypertension, with potential sex-specific differences in this association. These findings suggest that enhancing oral microbiome diversity may potentially help promote overall health in individuals with hypertension.

Background: Periodontitis progression is accompanied by a succession of the oral microbiome. However, the dynamic microbial transitions that link different disease stages and contribute to disease progression remain incompletely understood.

Objective: This study aims to identify microbial taxa that may serve as potential drivers underlying increasing severity of periodontitis.

Design: Subgingival sample 16S rRNA gene sequencing data were reprocessed for quality control and taxonomic annotation. MaAsLin2 was used to identify microbial differences between groups, and co-occurrence networks were built based on the differential taxa. NetMoss algorithm was applied to identify key microbes driving the transition from health to periodontitis. Correlation and mediation analyses were used to assess the associations between these driver taxa and periodontal clinical indicators.

Results: Putative novel pathogens (e.g. Filifactor alocis, Slackia exigua) were markedly enriched in periodontitis, whereas potential protective taxa (e.g. Haemophilus and Rothia) had higher relative abundance in the health group. The microbial co-occurrence networks in the periodontitis groups were progressively disrupted, characterized by reduced network robustness and heightened vulnerability in the Stage III and IV groups. The driver taxa probably influenced the severity of periodontitis through modulation of periodontal clinical indicators, with positive or negative correlations observed between these taxa and periodontal clinical indicators.

Conclusions: Capnocytophaga, Paludibacter, Dialister pneumosintes, Eubacterium minutum and Phocaeicola abscessus are proposed as key driver taxa across different periodontal health conditions, and exhibited significant correlations with periodontal clinical indicators.

Background: Hepatitis B virus-related chronic liver disease (HBV-CLD), chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC) patients' tongue coating microbiota dysbiosis has not yet been clearly defined.

Objectives: We aimed to reveal shifts in the bacterial composition of tongue coating microbiota during the progression of HBV-CLD in three different phases.

Design: We examined tongue coating microbiota of 16 healthy individuals and 81 patients with HBV-CLD, including 25 with CHB, 27 with LC, and 29 with HCC, using 16S rRNA gene sequencing technique.

Results: The bacterial richness in tongue coating was higher in patients with HBV-CLD (all P < 0.05) than in healthy controls. A clear clustering pattern between patients with HBV-CLD and healthy controls is shown using beta diversity analysis (all p < 0.05). Linear discriminant analysis revealed multiple taxa that varied significantly in abundance between healthy controls and patients with HBV-CLD; Firmicutes were higher in patients with LC and HCC, whereas CHB patients had higher levels of Bacteroidetes. PICRUSt2 analysis of the sequencing data revealed changes in microbial activity with disease development.

Conclusions: Our investigation revealed tongue coating microbiota dysbiosis in patients with HBV-CLD, which may offer unique diagnostic possibilities and provide microbial biomarkers for monitoring disease progression.

Objective: The oral-gut axis, the pathway by which oral bacteria reach the intestine, has recently attracted attention. However, no recent studies have isolated live Streptococcus mutans, a major pathogen of dental caries, in the gastrointestinal tract. In the present study, we isolated S. mutans from the gastrointestinal tract of corpses.

Methods: Fifty corpses from forensic autopsies (ages 0-94 years, median age 49) were used. Samples were taken from the oral cavity and gastrointestinal tract (esophagus, stomach, duodenum, small intestine, and large intestine) using sterile swabs. S. mutans isolates was cultured from the swabs, and DNA and RNA of the bacteria were extracted for genetic analysis.

Results: S. mutans was isolated from each organ with the following frequency: oral cavity, 14 cases (28%); esophagus, 3 cases (6%); stomach, 1 case (2%); duodenum, 0 cases (0%); small intestine, 1 case (2%); and large intestine, 4 cases (8%). When S. mutans strains isolated from the oral cavity and gastrointestinal tract of the same corpses were compared, the serotypes and genotypes were completely consistent. Bioinformatic analysis showed that gene expression and predicted functions differed between S. mutans strains isolated from the oral cavity and the gastrointestinal tract, even though these S. mutans strains were the same genotype.

Conclusion: These results suggest that S. mutans strains existing in the gastrointestinal tract may undergo changes in gene expression to adapt to the environment of each organ.

Background: Implementing local adjunctive therapy during scaling and root planing has become increasingly crucial for optimizing the therapeutic efficacy of periodontitis and reshaping the periodontal microecological environment.

Objective: This study aimed to reveal the additional clearance effect of local adjunctive therapy on the microbiota of periodontitis.

Design: An autologous randomized controlled trial included 25 periodontitis patients. After scaling and root planing, one oral side randomly received laser or minocycline, the other as control. Three hundred and seventy-six subgingival samples were collected at nine time points within 1 month for integrated analysis of microbiota and clinical indicators.

Results: Compared with laser adjunctive therapy, minocycline hydrochloride adjunctive therapy showed no difference in pathogen clearance rate within 6 h, but significant differences emerged in days 1, 3 and 7 (χ² test, P < 0.05). Meanwhile, within the 7-day period, the number of core bacteria of periodontitis with significant intergroup differences increased progressively over time (LDA > 2.0, P < 0.05). After 4 weeks, minocycline hydrochloride adjunctive therapy eliminated 12 more core bacteria of periodontitis than scaling and root planing alone, while significantly reduced the bleeding on probing (Wilcoxon test, p = 0.0085) and clinical attachment loss indicators (Wilcoxon test, p = 0.0456). In the long term, minocycline hydrochloride adjunctive therapy weakened microbial network connectivity, strongly influencing bacterial interactions involving Leptotrichia, Dialister and Atopobium.

Conclusions: Minocycline hydrochloride local adjunctive therapy outperforms semiconductor laser local adjunctive therapy in terms of eliminating periodontitis core bacteria, improving the microbial community structure, and enhancing clinical indicators.

Background: Peri-implantitis, driven by microbial‒host immune interactions, is the leading reason that dental implants fail. Implant surface design plays a crucial role in microbial colonization.

Objective: To investigate how surface characteristics of implant materials impact periodontal disease biofilm formation and host immune response.

Design: Biofilms, cultured on Ti-6Al-4V and CoCr disks, had biomass quantified by crystal violet and microbial populations by agar enumeration. We assessed the influence of Ti-6Al-4V post-processing treatments on surface chemistry (energy dispersive spectroscopy), topography (optical profilometry) and microbial dynamics (through complex oral biofilm culture and 16S rRNA sequencing). To evaluate immune responses, biofilms were co-cultured with dysplastic oral keratinocytes, and IL-6, IL-8, IL-1β, TNFα and GRO-α ELISAs were performed.

Results: Sandblasting markedly increased surface roughness (3.9 vs 0.2-0.6 R_a), biomass (0.72-0.99 vs 0.13-0.62 AU) and total viable counts (TVC). Ti-6Al-4V demonstrated significant enrichment of firmicutes compared to CoCr, together with increased proportions of sulphate-reducing and periodontal disease-associated taxa. Rougher surfaces provoked stronger immune activation under microbial challenge, highlighting the link between topography and host response.

Conclusions: Surface roughness influenced biofilm formation and inflammation. Assessment of implant materials should integrate microbial and cellular responses for deeper insights. Smoother surfaces, combined with antimicrobial coatings may help reduce peri-implant disease.

Background: This study evaluated the antimicrobial effect of cannabidiol (CBD) on a multi-species subgingival biofilm model.

Materials and methods: Biofilms were formed using 33 bacterial species on a Calgary device. Two protocols were tested: (A) biofilm in contact with CBD (125, 250 and 500 µg/mL) and chlorhexidine 0.12% (CHX) for the entire period; (B) treatments with CBD (500 and 1000 µg/mL) and CHX started on day 3, twice a day, for 1 minute. The total biofilm counts, the proportion of complexes, and the counts of each species were evaluated by DNA-DNA hybridization (Checkerboard).

Results: In Experiment A, CBD at concentrations of 250 and 500 µg/mL, as well as CHX, significantly reduced the total biofilm count. At 500 µg/mL, CBD also decreased the proportion of the red complex and reduced the counts of 10 bacterial species, whereas CHX affected 20 species. In Protocol B, both CBD at 1000 µg/mL and CHX reduced the total biofilm count and the proportion of the red complex, while increasing the proportion of the green complex. Both protocols led to a reduction in Porphyromonas gingivalis and Tannerella forsythia.

Conclusion: CBD reduced the total bacterial count and the red complex, inhibiting known periodontal pathogens. Within the limitations, the results provide exploratory evidence that CBD may reduce the total bacterial count in the proposed polymicrobial biofilm model, including the red complex bacteria, and may thus be postulated as an inhibitor of known periodontal pathogens. However, future in vivo studies with robust sample sizes and standardized CFU-based quantification are required to confirm these findings.