Binge-eating spectrum disorders, including bulimia nervosa (BN) and binge-eating disorder (BED), have psychological, behavioral, and physical effects, which present significant challenges for accurate diagnosis and treatment. Identifying biomarkers is thus of relevance to improve diagnostic and treatment strategies.

Saliva collected from female individuals with BED (n = 20), BN (n = 17), and normal weight healthy controls (NW-HC) (n = 20) was analyzed to assess salivary microbiome, exosomal miRNA expression, and DNA methylation of dopaminergic system gene components.

Microbial diversity was significantly reduced in BED and BN groups compared to NW-HC. Differential abundance analysis revealed that Bacilli (class-level) were enriched in BN and BED, while Lachnospirales (order-level) were significantly depleted in BN compared to NW-HC. In total, 79 miRNAs were differentially expressed in patients compared with controls. Alteration in four of these miRNAs (let-7b-5p, mir-15b-5p, mir-429, and mir-221-3p) identified via network analysis as potentially relevant to psychiatric disorders, were confirmed to be significantly upregulated in both BED and BN compared with controls. Significant hypomethylation at specific CpG sites of the DAT1 gene was also observed in BED and BN groups relative to controls. Correlation analysis highlighted significant associations between specific microbiota genera, miRNA expression, and DNA methylation of DAT1 in both the BED and BN groups.

Our findings provide new evidence on the role of epigenetic modifications linked to alterations in salivary microbial composition and diversity in BED and BN, opening new avenues for future research and therapeutic interventions in eating disorders targeting miRNAs and microbiota.

Most studies on pregnant women focus on analyzing individual microbial species at specific body sites. This study aims to explore the characteristics, functions, and microbial networks of the oral, placental, and gut microbiota in healthy pregnant women.

A total of 23 healthy pregnant women were enrolled in this study. We analyzed the microbial composition, functional profiles, and microbial networks of the oral, placental, and gut microbiota using 16S rRNA gene sequencing.

Our findings revealed significant differences in microbial composition across these three sites. The placental microbiota contained a relatively high proportion of low-abundance microorganisms, which were more diverse and evenly distributed compared to the gut and oral microbiota. The microbial composition at each site displayed distinct characteristics, likely influenced by environmental, physiological, and biological factors. The placental microbiota exhibited a complex network of tightly interconnected genera, whereas the gut microbiota showed sparser connections, with fewer closely related genera compared to the placental and oral microbiota. Functional differences were also observed among the three microbiota, with each playing a unique role in maintaining host health and metabolic balance. While the oral and gut microbiota shared functional similarities, the placental microbiota exhibited distinct functional characteristics.

This study provides valuable insights into the microbial communities of healthy pregnant women, offering important data for microbiological research during pregnancy and laying the foundation for future investigations into the roles of these microbial communities in maternal health.

Developing and utilizing effective local antimicrobial agents can help treat periodontitis while minimizing the risks associated with systemic antibiotic use. Recent studies have shown that the mucosal adhesion properties of hydrogels can play a potential role in the treatment of periodontitis. The hydrogel can improve the contact and retention time of drugs in the periodontal pocket. Through the adhesion of mucosa, it interacts with the mucin coating surface of epithelium and teeth to form a specific interface force. The hydrogel exhibits strong mucosal adhesion (adhesion strength: 5-6 N/cm2) and prolonged retention in periodontal pockets (≥6 h), enabling sustained drug release through dynamic sol-gel transitions triggered by pH and reactive oxygen species (ROS). This design overcomes the limitations of poor mechanical stability in conventional formulations. The dynamic balance of oral microbiota plays an important role in maintaining oral health. Probiotics, by colonizing the oral cavity, transform the infected site from an environment rich in inflammatory cytokines to a more benign environment, inhibit harmful pathogenic microorganisms, and contribute to overall health. Microenvironment sensitive hydrogels can perform dynamic sol gel transformation in situ, and can accurately control drug release when exposed to various stimuli (such as temperature change, light, pH change, reactive oxygen species, etc.). Oral probiotics and anti-inflammatory drugs are encapsulated in hydrogels to inhibit the proliferation and adhesion of oral pathogens by planting in the mouth and producing metabolites, effectively preventing and treating oral diseases.

Antibiotics are used in periodontal therapy in selected cases, but therapy is rarely guided by antimicrobial susceptibility testing (AST). Direct AST of the oral microbiota using a combination disk with different antibiotics could provide a new way of AST to guide treatment planning.

We performed AST of 46 strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum complex, Prevotella species, and Porphyromonas gingivalis, with a combination disk of amoxicillin (AMX) and metronidazole (MET). The AMX-MET was compared to the largest inhibition zone diameter (IZD) obtained with AMX or MET disks, using an ordinary least square linear regression model.

The IZD of the AMX-MET correlated with the AMX for A. actinomycetemcomitans (interception 0.3) and with the MET for Fusobacterium (interceptions -1.25). For Prevotella, the AMX-MET was compared to AMX and MET after 20 and 44 h resulting in a superior correlation after 20 h (interception 0.06 vs 6.61 after 44 h). For P. gingivalis, the AMX-MET was compared to MET after 44 h resulting in an inferior correlation (interception 16.65).

The IZD of AMX-MET was comparable to that of AMX and MET for important periodontal pathogens, which opens for studies on direct AST of oral samples with a mixed microbiota.

The amoxicillin-metronidazole disk for antimicrobial susceptibility testing results in comparable inhibition zone diameters to that of AMX and MET for important periodontal pathogens.

Enterococcus faecalis, a non-oral nosocomial pathogen, intriguingly ranks among the most frequently retrieved species from polymicrobial infections of dental root canals. This review integrates findings from the latest omics approaches, alongside emerging evidence of E. faecalis interactions within oral polymicrobial communities, to refine our understanding of its role in these infections. Herein, E. faecalis emerges as an ecologically invasive species and a catalyst of the pathogenicity of entire communities.

Background/Objectives: Oral health is a complex concept involving physical, psychological, emotional, and social components. A key factor in maintaining oral tissue integrity is redox balance, which is disrupted by oxidative stress (OS) through an imbalance between reactive oxygen species (ROS) and antioxidant defenses. This study examines the contribution of endogenous and exogenous sources to OS and explores the therapeutic potential of medicinal plants from the Asteraceae and Lamiaceae families in restoring redox homeostasis and improving oral health. Methods: A literature review was conducted, analyzing the role of OS in oral diseases and the antioxidant mechanisms of selected Asteraceae species. Special attention was given to their phytochemical contents-polyphenols, flavonoids, and essential oils-and their biological relevance to oral health. Results: OS plays a critical role in the onset and progression of oral conditions such as caries, periodontitis, gingivitis, aphthous ulcers, abscesses, precancerous lesions, and oral cancers. ROS and reactive nitrogen species (RNS) cause inflammation, tissue breakdown, and salivary gland dysfunction. Asteraceae plants like Matricaria chamomilla, Calendula officinalis, Cichorium intybus, Taraxacum officinale, Arctium lappa, Achillea millefolium, and Solidago virgaurea demonstrate notable antioxidant, anti-inflammatory, and antimicrobial properties that help counteract OS and support oral homeostasis. Conclusions: Asteraceae and Lamiaceae species show high therapeutic potential in addressing OS-related oral disorders. Their bioactive compounds aid in restoring redox balance and protecting oral tissues. These findings support the integration of phytotherapeutic agents into oral healthcare and call for further clinical validation of plant-based strategies for disease prevention and management.

The oral microbiota is an essential microbial community within the human body, playing a vital role in maintaining health. In older adults, age-related changes in the oral microbiota are linked to both systemic and oral health impairments. The use of various medications for systemic diseases in the elderly can also contribute to the development of oral diseases. Oral microbiota dysbiosis refers to an imbalance in the composition of oral microbial communities. This imbalance, along with disruptions in the host immune response and prolonged inflammation, is closely associated with the onset and progression of several diseases. It contributes to oral conditions such as dental caries, periodontal disease, and halitosis. It is also linked to systemic diseases, including Alzheimer's disease, type 2 diabetes mellitus, rheumatoid arthritis, atherosclerotic cardiovascular disease, and aspiration pneumonia. This review aims to explore how oral microbiota influences specific health outcomes in older individuals, focusing on Alzheimer's disease, type 2 diabetes mellitus, rheumatoid arthritis, atherosclerotic cardiovascular disease, and aspiration pneumonia. The oral microbiota holds promise as a diagnostic tool, therapeutic target, and prognostic biomarker for managing cardiovascular disease, metabolic diseases, infectious diseases and autoimmune diseases. Emphasizing proper oral health care and instilling an understanding of how drugs prescribed for systemic disease impact the oral microbiome, is anticipated to emerge as a key strategy for promoting the general health of older adults.

Surface-enhanced Raman spectroscopy (SERS) is a transformative tool for infectious disease diagnostics, offering rapid and sensitive species identification. However, background spectra in biological samples complicate analyte peak detection, increase the limit of detection, and hinder data augmentation. To address these challenges, we developed a deep learning framework utilizing dual neural networks to extract true virus SERS spectra and estimate concentration coefficients in water for 12 different respiratory viruses. The extracted spectra showed a high similarity to those obtained at the highest viral concentration, validating their accuracy. Using these spectra and the derived concentration coefficients, we augmented spectral data sets across varying virus concentrations in water. XGBoost models trained on these augmented data sets achieved overall classification and concentration prediction accuracy of 92.3% with a coefficient of determination (R2) > 0.95. Additionally, the extracted spectra and coefficients were used to augment data sets in saliva backgrounds. When tested against real virus-in-saliva spectra, the augmented spectra-trained XGBoost models achieved 91.9% accuracy in classification and concentration prediction with R2 > 0.9, demonstrating the robustness of the approach. By delivering clean and uncontaminated spectra, this methodology can significantly improve species identification, differentiation, and quantification and advance SERS-based detection and diagnostics.

Epidemiological studies show firefighters have increased risks of cancer, diabetes, and cardiovascular disease. To explore links between occupational/environmental exposures and dysbiosis-associated health risks, this case-control study compared oral microbiota of age-matched firefighters (n = 13) and non-firefighters (n = 13) using next-generation sequencing. Firefighters exhibited significantly reduced overall microbial diversity (p ≤ 0.05) and compositional shifts. Firmicutes increased from 53.5% to 68.5%, and Bacteroidetes from 9.5% to 14.1%, while Proteobacteria decreased from 24.6% to 8.3%, and Fusobacteria from 3.3% to 1.1%. This resulted in a higher Firmicutes to Bacteroidetes ratio (5.63 vs. 4.89 in controls), indicating a pro-inflammatory oral microenvironment. At the family level, Streptococcaceae (45.1% to 60.3%) and Prevotellaceae (6.2% to 10.0%) increased, whereas Neisseriaceae (17.7% to 4.9%) and Fusobacteriaceae (2.1% to 0.8%) decreased. The genus Streptococcus dominated firefighters' microbiota, rising from 45.1% to 60.3%. Diversity indices confirmed reduced microbial evenness and richness in firefighters. Metadata analysis linked frequent fire exposures to perturbations in Comamonadaceae and Carnobacteriaceae (p ≤ 0.05). Barbecue consumption, a source of polycyclic aromatic hydrocarbons, correlated with elevated Spirochaetaceae and Peptostreptococcaceae. This first report on oral dysbiosis in firefighters reveals significant alterations in microbiota abundance, diversity, and evenness, implying potential health risks for this group.

Evidence indicates a connection between periodontitis (PD) and systemic lupus erythematosus (SLE), though the underlying co-morbid mechanisms remain unclear. This study sought to identify the genetic factors and potential therapeutic agents involved in the interaction between PD and SLE. We employed multi-omics methodologies, encompassing differential expression analysis, weighted gene co-expression network analysis (WGCNA), functional enrichment (GO/KEGG), LASSO regression, diagnostic model construction, protein-protein interaction (PPI) networks, immune infiltration profiling, computational drug prediction, molecular docking, and disease subtyping, to analyze PD and SLE expression datasets from the Gene Expression Omnibus (GEO) database (GSE10334, GSE16134, GSE50772, and GSE81622). Cross-analysis identified 32 crosstalk genes (CGs) common to both PD and SLE. LASSO analysis pinpointed three key diagnostic genes (TAGLN, MMP9, TNFAIP6) for both conditions. The resulting diagnostic models demonstrated robust efficacy in both training and validation datasets. Four topological algorithms in Cytoscape highlighted four central crosstalk genes (TAGLN, MMP9, TNFAIP6, IL1B). Additionally, hesperidin, doxycycline, and cytochalasin D emerged as potential therapeutic agents. Two subtypes (C1 and C2) of PD and SLE were delineated based on CG expression profiles. The development of diagnostic models, potential drug identification, and disease subtype classification are poised to enhance diagnosis and treatment. These findings aim to deepen the understanding of PD and SLE complexities.

Emerging evidence links oral-derived gut microbes to colorectal cancer (CRC) development, but CRC prognosis-related microbial alterations in oral remain underexplored. In a retrospective study of 312 CRC patients, we examined the oral microbiota using 16S rRNA gene full-length amplicon sequencing to identify prognostic microbial biomarkers for CRC. Neisseria oralis and Campylobacter gracilis increased CRC progression risk (HR = 2.63 with P = 0.007, HR = 2.27 with P = 0.001, respectively), while Treponema medium showed protective effects (HR = 0.41, P = 0.0002). A microbial risk score (MRS) incorporating these species effectively predicted CRC progression risk (C-index = 0.68, 95% CI = 0.61-0.76). When compared to a model constructed solely from clinical factors, including tumor stage, lymphatic metastasis, and perineural invasion, the predictive accuracy significantly improved with the addition of the MRS, resulting in a C-index rising to 0.77 (P = 2.33 × 10-5). Our findings suggest that oral microbiota biomarkers may contribute to personalized CRC monitoring strategies, their implementation in clinical surveillance necessitates confirmatory studies.

(1) The link between periodontal disease (PD) and acute coronary syndromes (ACSs) is predominantly attributed to the atherosclerotic process, mediated by systemic inflammation. However, the correlation between the severity of PD, characterized by the presence of periodontal pathogens, and systemic inflammation in patients with ACS remains inadequately clarified. (2) This study aims to assess the association between the severity of PD and systemic inflammatory biomarkers, along with lipid profiles, in patients with ACS. (3) In total, 42 patients with ACS and concomitant PD were divided into two groups based on the presence of periodontal pathogens belonging to the red or red-orange complexes. Group 1-29 patients displayed pathogens from the red complex (RC) and group 2-13 patients displayed pathogens from the red-orange complex (ROC). All participants underwent a comprehensive dental examination, including DNA sampling from the periodontal pockets for pathogen detection. Systemic inflammation was evaluated alongside assessments of lipid profiles. (4) Inflammatory markers were more pronounced in the RC group compared with the ROC group. Moreover, patients in the RC group showed significantly higher monocyte-to-lymphocyte ratios (0.41 ± 0.20 vs. 0.28 ± 0.12; p = 0.002), platelet-to-lymphocyte ratios (139.50 ± 33.85 vs. 100.90 ± 8.84; p = 0.02), serum C-reactive protein levels (9.34 ± 1.08 mg/L vs. 5.46 ± 1.03 mg/L; p = 0.03), and serum uric acid levels (6.9 ± 0.49 mg/dL vs. 5.4 ± 0.26 mg/dL; p = 0.006). Concerning lipid profiles, the RC group exhibited significantly higher low-density lipoprotein cholesterol (LDL) levels (169.60 ± 12.63 mg/dL vs. 106.70 ± 9.34 mg/dL; p = 0.0007) and significantly lower high-density lipoprotein cholesterol (HDL) levels (29.29 ± 3.50 mg/dL vs. 39.56 ± 2.07 mg/dL; p = 0.002). (5) The severity of PD, indicated by the concomitant presence of pathogens from the red and orange complexes, is associated with an unfavorable lipid profile and elevated inflammatory biomarkers. These findings highlight the potential importance of periodontal intervention in the prevention of ACS.

Nitrate, an inorganic anion found in various foods is also present in saliva and has emerged as a potential prebiotic for the oral microbiome. Salivary glands concentrate nitrate from the bloodstream and release it into the oral cavity via the anion transporter sialin SLC17A5. In previous studies dietary nitrate supplementation altered oral bacteria composition, favouring genera like Rothia and Neisseria while reducing Streptococcus, Veillonella, Prevotella, and Actinomyces. The present study hypothesized that taste intensity might adapt to changes in the oral microbiome caused by nitrate supplementation. Participants underwent taste tests before, during, and after supplementation. All subjects showed greater levels of salivary nitrate during supplementation and had higher levels of Neisseria compared to before. Subjects were then grouped according to taste tests (before vs. during) as responders (ANOVA p < 0.05, n = 7), and non-responders (ANOVA p > 0.05, n = 6) and their salivary metabolome and oral microbiome further analysed. Responders had significantly less 5-amino pentanoate, formate, propionate and butyrate in saliva while non-responders showed no metabolite changes between before and during supplementation. In contrast, non-responders had increased Capnocytophaga gingivalis and altered lysosomal degradation pathways. Overall, nitrate supplementation shifted the oral microbiome composition in all subjects and when taste intensity was altered this correlated to bacteria-derived short-chain fatty acid production. This suggests taste perception is affected by the oral microbiome.

Cancers of the oral cavity, lip, salivary gland, and oropharynx cause substantial global disease burden. While tobacco-use and alcohol use are highly associated with oral cancers, the rising incidence of disease in patients who do not use tobacco or alcohol points to additional carcinogenic risk factors. Chronic inflammation, disruption of the oral microbiome, and dysbiosis are becoming more widely implicated in the pathogenesis of oral cancer. Several studies have identified specific bacterial species enriched in patients with oral cancer, including Porphyromonas gingivalis and Fusobacterium nucleatum. In this narrative review, we describe potential carcinogenic mechanisms exhibited by these species and other microbes in the development of oral cancer.

This study investigated the multifunctional oral cavity simulator (MOCS) in terms of microbial composition, functional profile, and dentin root demineralization. Microcosm biofilms were grown on dentin using human saliva for 4, 7, and 14 days, with exposure to sucrose and a mucin-enriched medium. Biofilms were analyzed for microbial viability and composition through CFU count and 16S-rRNA gene sequencing. Demineralization was quantified by percentage surface hardness change (%SHC), mineral loss (ML), and lesion depth (LD). The results showed microbial viability at all time points. After 7 days, aciduric/acidogenic and proteolytic organisms increased in abundance. The functional profile reflected the oscillations in microbial composition. No significant differences in %SHC, ML, or LD were observed across the time points. Carious lesions exhibited 60-70% SHC and 125-200 µm depth. MOCS was able to induce root carious lesions as result of microcosm biofilm metabolic activity, indicating its potential use in preclinical studies on root dentin caries.

To evaluate the clinical applicability of nano silver fluoride sustained release orthodontic elastomerics (NSF-RE) by investigating its effects on inhibiting biofilm formation and enamel demineralization using dental microcosm biofilms.

Two types of 23 % NSF coating solutions were prepared depending on the presence or absence of the plasticizer (polyethylene glycol [PEG] 6000: NSF-EP and NSF-E); the elastomerics were dip-coated individually with these. Biofilms were allowed to form on bovine enamel specimens with the elastomerics. Biofilm maturity (red/green ratio) was measured. After 7 days, biofilm thickness, live/dead cell ratio, and cell viability were evaluated. Microbiome taxonomic profiling was conducted on days 3 and 7. Mineral loss beneath the biofilm was quantified from fluorescence loss (ΔF) and ΔFmax values obtained. Demineralization at varying distances from the specimen center was evaluated based on the difference in ΔF between the control and experimental groups.

The NSF-EP (elastomerics treated with NSF coating containing PEG) had a 6.7 % significantly lower R/G ratio from day 3 and a 36.1 % thinner biofilm compared to the negative control with uncoated elastomerics. In the NSF-EP group, cell viability assessments indicated reductions in total and aciduric bacterial counts by 9.4 % and 13.0 %, respectively. NSF-EP also had the lowest relative abundance of five caries-related bacteria. Additionally, NSF-EP significantly increased ΔF and ΔFmax by 34.8 % and 38.7 %, respectively, indicating reduced mineral loss. Demineralization did not differ according to distance from the elastomerics.

NSF-RE significantly reduces biofilm formation and demineralization, offering a promising caries prevention strategy in orthodontic patients.

By inhibiting both biofilm formation and demineralization, NSF-RE provides a dual-function approach that may effectively prevent dental caries in orthodontic patients.

Menopause is characterized by the cessation of menstruation and a decline in reproductive function, which is an intrinsic component of the aging process. However, it has been a frequently overlooked field of women's health. The oral and gut microbiota, constituting the largest ecosystem within the human body, are important for maintaining human health and notably contribute to the healthy aging of menopausal women. Therefore, a comprehensive review elucidating the impact of the gut and oral microbiota on menopause for healthy aging is of paramount importance. This paper presents the current understanding of the microbiome during menopause, with a particular focus on alterations in the oral and gut microbiota. Our study elucidates the complex interplay between the microbiome and sex hormone levels, explores microbial crosstalk dynamics, and investigates the associations between the microbiome and diseases linked to menopause. Additionally, this review explores the potential of microbiome-targeting therapies for managing menopause-related diseases. Given that menopause can last for approximately 30 years, gaining insights into how the microbiome and menopause interact could pave the way for innovative interventions, which may result in symptomatic relief from menopause and an increase in quality of life in women.

Schizophrenia is a chronic and thoughtful psychological disorder that affects a person's thinking, feelings, and behaviours. Multi-factorial genetic, environmental, and neurological variables cause it. Recently, more research focused on the human microbiome, which alters the immune system and develops adverse health effects on the human body. The study discusses a possible relationship between the oropharyngeal microbiome and schizophrenia. According to recent studies, the oropharyngeal microbiome may alter the immune system in the human body and cause various psychiatric disorders, including schizophrenia. The oropharyngeal microbiome can cause schizophrenia either by affecting the genes, chromosomes, and immune system in the human body. Additionally, it examines the combined mechanism of how the oropharyngeal microbiome's alterations lead to genetic abnormalities and immune dysregulation in schizophrenia. By combining the various approaches, this chapter offers a comprehensive view of the oropharyngeal microbiome's role in schizophrenia and suggests that microbial alterations could serve as biomarkers or therapeutic targets for the disorder.

Hypertension is a prevalent metabolic disorder in the elderly, with its pathogenesis linked to gut microbiota dysbiosis. Recent studies suggested that oral microbiota may also play a role in hypertension development, yet its relationship with hypertension in the elderly remains underexplored.

This cross-sectional study aimed to examine the structure of the oral microbiota and its association with hypertension in elderly patients, providing insights into hypertension prevention and treatment.

A total of 206 subjects (60-89 years) were categorized into normal (CON) and hypertensive (HTN) groups, based on the Chinese Hypertension Guidelines. Saliva samples were analyzed using 16S rRNA gene sequencing.

Oral microbiota composition was significantly influenced by blood pressure. At the phylum level, Synergistetes and Spirochaetes were more significantly abundant in the HTN group, while at the genus level Treponema and Leptothrix was higher, Actinomyces and Capnocytophaga were lower in HTN. Random Forest analysis identified 15 key microbiota as strong discriminators of HTN (AUC 0.74). Blood pressure was negatively correlated with Actinomycetes and positively correlated with Leptothrix. PICRUST2 analysis revealed elevated chlorinated compound degradation in HTN patients.

This study identified distinct oral microbiota in elderly hypertensive patients, highlighting the role of the oral microbiome in hypertension pathogenesis.

With the development of society, ecological and environmental problems have gradually become the focus of attention of countries around the world, among which environmental particulate matter poses a major harm to health. This article elucidates the association between environmental particulate matter and dental caries and provides new insights into the underlying mechanisms. In addition, this study emphasizes the role of oxidative stress in the occurrence and development of dental caries, and a new research pathway based on the interaction between oxidative stress and dental caries based on the Nrf2 pathway has become the focus of future research on the pathogenesis of dental caries. The relevant content of this review can provide a certain theoretical basis for the follow-up multidisciplinary joint research of researchers, and provide a certain reference for public health personnel and policymakers to formulate prevention strategies and public health interventions, carry out more accurate individualized treatment for high-risk groups, implement key prevention and treatment, and promote the overall improvement of effective prevention and treatment of caries. Ultimately, more attention must be paid to addressing the relationship between environmental particulate pollution and dental caries, with a focus on pollution control and reducing preventable environmental risks in order to protect oral health more broadly.

The present study aimed to characterize the salivary microbiota in patients with catathrenia and to longitudinally validate potential biomarkers after treatment with mandibular advancement devices (MAD).

Twenty-two patients with catathrenia (12 M/10 F, median age 28 y) and 22 age-matched control volunteers (8 M/14 F, median age 30 y) were included in the cross-sectional study. Video/audio polysomnography was conducted for diagnosis. All patients received treatment with custom-fit MAD and were followed for one month. Ten patients (6 M/4 F) underwent post-treatment PSG. Salivary samples were collected, and microbial characteristics were analyzed using 16S rRNA gene sequencing. The 10-fold cross-validated XGBoost and nested Random Forest Classifier machine learning algorithms were utilized to identify potential biomarkers.

In the cross-sectional study, patients with catathrenia had lower α-diversity represented by Chao 1, Faith's phylogenetic diversity (pd), and observed species. Beta-diversity based on the Bray-Curtis dissimilarities revealed a significant inter-group separation (p = 0.001). The inter-group microbiota distribution was significantly different on the phylum and family levels. The treatment of MAD did not alter salivary microbiota distribution significantly. Among the most important genera in catathrenia and control classification identified by machine learning algorithms, four genera, Alloprevotella, Peptostreptococcaceae_XI_G1, Actinomyces and Rothia, changed significantly with MAD treatment. Correlation analysis revealed that Alloprevotella was negatively related to the severity of catathrenia (r2= -0.63, p < 0.001).

High-throughput sequencing revealed that the salivary microbiota composition was significantly altered in patients with catathrenia. Some characteristic genera (Alloprevotella, Peptostreptococcaceae_XI_G1, Actinomyces, and Rothia) could be potential biomarkers sensitive to treatment. Future studies are needed to confirm and determine the mechanisms underlying these findings.

Bacteriophages (phages) play a crucial role in shaping the composition and diversity of the human microbiome across various body niches. Recent advancements in high-throughput sequencing technologies have enabled comprehensive analysis of the human phageome in different body sites. This review comprehensively analyzes phage populations across major human body niches, examining their distribution and dynamics through recent metagenomic discoveries. We explore how phage-bacteria interactions within different body sites contribute to homeostasis and disease development. Emerging evidence demonstrates that phageome perturbations can serve as early indicators of various disorders, particularly in the gut microbiome. Understanding these complex microbial interactions offers promising opportunities for developing novel diagnostic markers and therapeutic approaches. However, the causal relationship between phages, bacteria, and disease development remains unclear. Further research is needed to elucidate the role of phages in human health and disease and to explore their potential as diagnostic or therapeutic tools. Understanding the intricate interactions between phages, bacteria, and the human host is crucial for unraveling the complexities of the human microbiome and its impact on health and disease.

Sjögren's syndrome is an autoimmune disease characterized by lymphatic infiltration of secretory tissues. The disease results in dryness of the eyeball or mouth, which often occur simultaneously. Agents used to treat Sjögren's syndrome may improve oral hydration and the patient's quality of life. There are several pharmacological and non-pharmacological agents used to treat significant problem like xerostomia. The use of appropriate medicines (i.e. pilocarpine and cevimeline) may cause changes in the local microbiome, which is very sensitive to quantitative changes in water. As a result of Sjögren's syndrome, a new balance of the microbiome is established in the oral cavity, which, if disturbed by medical measures, may increase the risk of oral lesions (such as periodontopathies or caries) or reduce this risk. Overall, the knowledge regarding microbiological aspects and agents treating oral dryness is still not well described but initial results indicate some microbial alterations.

The portal to the gastrointestinal tract is the oral cavity, with transient and permanent microbial residents. Oral pathogens are implicated in the aetiology of several chronic conditions. To date, the role of oral health and the oral microbiota in the aetiology of pain in sensitisation disorders have not been explored. Here, we examined associations between self-reported oral health, the oral microbiome, and various pain presentations in women.

Oral health in women was assessed using the WHO oral health questionnaire. Body pain, migraine, and abdominal pain were determined using validated instruments. Saliva samples were evaluated using metatranscriptomics for relative gene abundance. Demographic and clinical characteristics data were evaluated for relationships between oral health scores, pain measures, and the oral microbiota at three taxa levels.

Participants in the lowest quintiles for oral health were more likely to suffer migraine headaches (χ 2 = 23.24, df 4, p < 0.001) and higher body pain scores. Four oral pathogenic species were significantly associated with SF36 bodily pain (q < 0.05) after controlling for confounders. Relative abundance of Gardnerella (genus) correlated moderately with oral health scores (ρ = -0.346, q = 0.001), while Lancefieldella (genus) and Mycoplasma salivarius were associated with migraine.

Low oral health scores correlated with higher pain scores. Both were associated with higher relative abundance of oral pathobionts. This suggests a potential role for the oral microbiota in the aetiology of pain experienced by women with migraine headache and abdominal and body pain. These findings prompt consideration of an oral microbiome-nervous system axis.

The study was registered with the Australia and New Zealand Clinical Trials Registry (ANZCTR), registration number ACTRN12620001337965, on 11/12/2020 https://www.anzctr.org.au/, and with the World Health Organisation, UTN: U1111-1258-5108.

The symbiotic relationship between the oral microbiome and the host immune system is a prerequisite of oral health. Disruptions to this system can be associated with the development of diseases like dental caries. Introducing orthodontic treatments, such as aligners and fixed appliances, might impact this microbial ecosystem. This study evaluated potential changes in salivary microbiome and the level of inflammatory marker myeloid-related protein 8/14 in patients undergoing orthodontic treatment with aligners or fixed appliances.

Forty-eight patients were divided into two groups for treatment with fixed appliances or clear aligners. Unstimulated saliva samples were collected at baseline, three, and six months for microbiome analysis via 16 S rRNA sequencing and MRP-8/14 level measurement using ELISA.

Among 503 identified microbial species, no significant changes were noted in overall microbiome. A considerable increase of caries-relevant species could not be observed either. MRP-8/14 levels remained unchanged across treatments, indicating no alterations in the inflammatory level.

Orthodontic treatment with fixed or removable appliances does not significantly alter the salivary microbiome or influence inflammation, suggesting that these interventions are unlikely to affect oral health negatively.

This study investigates for the first time the association between metabolic syndrome and oral microbial profiles in a population-based sample from Rio de Janeiro, Brazil.

We assessed 66 volunteers, collecting detailed sociodemographic, anthropometric, and clinical data alongside salivary samples for metagenomic analysis.

Our findings reveal significant differences in anthropometric parameters, including waist circumference, glycemia, High-Density Lipoprotein (HDL), and triglycerides between the metabolic syndrome and control groups. Increased abundance of Bacteroidetes and Bacteroidia was observed in the metabolic syndrome group, suggesting a potential link between these phyla and metabolic dysregulation. While no significant differences in alpha diversity were found between the overall groups, stratification by body mass index (BMI) indicated that the normal weight subgroup without Metabolic Syndrome exhibited notable variations compared to overweight and obese individuals.

This study identifies specific shifts in oral microbiota composition that are associated with metabolic syndrome, highlighting their potential as microbial biomarkers for this condition. These findings suggest a link between oral dysbiosis and metabolic dysregulation, providing new insights into the pathophysiology of metabolic syndrome. Additionally, the results pave the way for the development of non-invasive diagnostics tools and targeted therapies that leverage the oral microbiome's role in systemic health.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and neuronal loss, affecting millions worldwide. Emerging evidence highlights the oral microbiome-a complex ecosystem of bacteria, fungi, viruses, and protozoa as a significant factor in cognitive health. Dysbiosis of the oral microbiome contributes to systemic inflammation, disrupts the blood-brain barrier, and promotes neuroinflammation, processes increasingly implicated in the pathogenesis of AD. This review examines the mechanisms linking oral microbiome dysbiosis to cognitive decline through the oral-brain and oral-gut-brain axis. These interconnected pathways enable bidirectional communication between the oral cavity, gut, and brain via neural, immune, and endocrine signaling. Oral pathogens, such as Porphyromonas gingivalis, along with virulence factors, including lipopolysaccharides (LPS) and gingipains, contribute to neuroinflammation, while metabolic byproducts, such as short-chain fatty acids (SCFAs) and peptidoglycans, further exacerbate systemic immune activation. Additionally, this review explores the influence of external factors, including diet, pH balance, medication use, smoking, alcohol consumption, and oral hygiene, on oral microbial diversity and stability, highlighting their role in shaping cognitive outcomes. The dynamic interplay between the oral and gut microbiomes reinforces the importance of microbial homeostasis in preserving systemic and neurological health. The interventions, including probiotics, prebiotics, and dietary modifications, offer promising strategies to support cognitive function and reduce the risk of neurodegenerative diseases, such as AD, by maintaining a diverse microbiome. Future longitudinal research is needed to identify the long-term impact of oral microbiome dysbiosis on cognition.

It is largely unknown which human genetic variants shape a person's oral microbiome and potentially promote its dysbiosis. We characterized the oral microbiomes of 12,519 people by analyzing whole-genome sequencing reads from previously sequenced saliva-derived DNA. Human genetic variation at 11 loci (10 novel) associated with differences in oral microbiome composition. Nearly all of these associations implicated candidate genes with readily interpretable functions, several related to carbohydrate availability. The strongest association ( p =3.0x10 -188 ) involved the common FUT2 W154X loss-of-function variant, which associated with the abundances of 32 bacterial species. Human host genetics also appeared to powerfully shape within-species genetic variation in oral bacteria. Variation at the 11 human loci associated with variation in gene dosages in 68 regions of bacterial genomes. Several such associations implicated interactions of bacterial proteins with histo-blood group antigens presented on host mucosal cell surfaces and salivary proteins. Common, multi-allelic copy-number variation of AMY1 , which encodes salivary amylase, associated with oral microbiome composition ( p =1.5x10 -53 ) and with dentures use in UK Biobank ( p =5.9x10 -35 , n=418k), suggesting that amylase abundance impacts oral health by influencing the oral microbiome. Two other microbiome composition-associated loci, FUT2 and PITX1 , also significantly associated with dentures risk, collectively nominating numerous microbial taxa that might contribute to tooth decay.

Predicting the time since deposition (TsD) of body fluid stain at a crime scene is highly valuable in forensic investigation, as it can connect a DNA-identified stain donor to a crime or estimate the post-mortem interval in forensic case involving cadaver. Previous study has demonstrated the applicability of microbial taxa for TsD prediction. In this proof-of-concept study, we explored the combined use of taxonomic and functional characteristics in human saliva microbiome for TsD prediction. We investigated the potential correlations between the temporal dynamics in microbial communities and the TsD of saliva stains, utilizing the relative abundance of microbial genera, amplicon sequence variants (AsVs), and the metabolic function pathway profiles. The results revealed that changes in the metabolic function pathway profiles of microbial communities could contribute to TsD estimation of the aged saliva stains. We developed ensemble models with multiple heterogeneous algorithms, also combined microbial species and metabolic function pathway profiles for TsD estimation. The TsD prediction model, developed using the relative abundance of the top 50 microbial genera and metabolic functional pathway profiles with the xgboost algorithm, achieved high accuracy (R2 = 0.76, mean absolute error = 6.28 days) in a 60-day deposition. Besides, we further interpreted the model and identified potential biomarkers for TsD estimation of saliva stains. The current study provided the first evidence to explore the potential of using multiple data modalities for predicting the TsD of aged saliva stains, offering valuable insight for forensic investigation.

The relationship between the oral microbiome and oral squamous cell carcinoma (OSCC) has been extensively investigated. Nonetheless, most previous studies were single-center, resulting in the absence of systematic evaluations. To address this gap, we performed a comprehensive meta-analysis on 1,255 samples from OSCC-related 16S rRNA gene data sets, representing a diverse range of OSCC phenotypes. It is recognized that the progression of cancer is related to the alterations in the microbiome among different phenotypes. Our findings revealed distinct microbiome characteristics among different sample types, with Biopsy (Bios) and Swab samples exhibiting significant differences between phenotypes. In Bios samples, the microbiomes of the Cancer group and the normal tissue adjacent to the tumor (NAT) group display a higher similarity, while both differ from the microbiome of the Fibroepithelial polyp (FEP) group. Moreover, the identified differential genera and pathways corresponded with these observations. We developed a diagnostic model using the random forest algorithm on Swab samples, achieving an area under the receiver operating characteristic curve (AUC) of 0.918. Importantly, this model exhibited considerable effectiveness (AUC = 0.849) when applied to another sequencing platform. Taken together, our study provides a comprehensive overview of the oral microbiome during various OSCC progression stages, potentially enhancing early detection and treatment.IMPORTANCEThis study answers key questions regarding the universal microbial characteristics and comprehensive oral microbiome dynamics during oral squamous cell carcinoma (OSCC) progression. By integrating multiple data sets, we examine the following critical aspects: (1) Do different sample types harbor distinct microbial communities within the oral cavity? (2) Which sample types offer greater potential for investigating OSCC progression? (3) How are the oral microbiomes of the Cancer group, normal tissue adjacent to the tumor group, and Fibroepithelial polyp group related, and what is their potential association with OSCC development? (4) Can a diagnostic model based on microbial signatures effectively distinguish between Cancer and Health groups using Swab samples?

Pancreatic cancer is a major cause of cancer-associated mortality globally, characterized by a poor prognosis and limited therapeutic response. The current approach for treating pancreatic cancer involves locoregional control with surgical resection and systemic therapy in the form of cytotoxic chemotherapy. However, despite standard-of-care treatment, the outcomes remain dismal. Emerging evidence suggests that the gut microbiota plays a significant role in pancreatic carcinogenesis through dysbiosis, chronic inflammation and immune modulation. Dysbiosis-driven alterations in the gut microbiota composition can disrupt intestinal homeostasis, promote systemic inflammation and create a tumor-permissive microenvironment in the pancreas. Moreover, the gut microbiota modulates the efficacy of systemic therapies, including chemotherapy and immunotherapy, by impacting drug metabolism and shaping the tumor immune landscape. This review is mainly focused on exploring the intricate interplay between the gut microbiota and pancreatic cancer, and also highlighting its dual role in carcinogenesis and the therapeutic response.

SUMMARYEnterococcus faecalis is a significant resident of the gastrointestinal tract of most animals, including humans. Although generally non-pathogenic in healthy hosts, this microbe is adept at the exploitation of compromises in host immune functions, resulting in life-threatening opportunistic infections whose treatments are complicated by a high degree of intrinsic and acquired resistance to antimicrobial chemotherapy. Historically, progress in enterococcal research was limited by a lack of experimental models that replicate natural infection pathways and the relevance of in vitro studies to the natural biology of the organism. In this review, we summarize the history of enterococcal research during the 20th and early 21st centuries and describe more recent genetic and genomic tools and screens developed to address challenges in the field. We also describe how the results of recent studies reveal the importance of previously uncharacterized enterococcal genes, and we provide examples of interesting determinants that have emerged as important contributors to enterococcal biology. These factors may also serve as targets for future vaccines and chemotherapeutic agents to combat life-threatening hospital infections.

Although many studies have associated changes in the nasopharyngeal microbiota to patient's susceptibility to COVID-19, their results are highly variable and contradictory. Addressing the limitations in previous research responsible for that variability, this study uses 16S rRNA gene sequencing to analyze the nasopharyngeal microbiota of 395 subjects, 117 controls, and 278 COVID-19 patients, of different age groups that cover the entire lifespan and across varying disease severities. This revealed that bacterial alpha diversity decreases progressively throughout life but only in severely ill COVID-19 patients, in whose nasopharynx, moreover, several opportunistic pathogen bacterial genera are overrepresented. Notably, Scardovia wiggsiae appears only in severe COVID-19 patients over 60 years of age, suggesting its potential utility as a COVID-19 severity biomarker in the elderly, who are the most susceptible individuals to suffer from serious forms of the disease. Thus, our results provide valuable insights into age-associated dynamics within nasopharyngeal microbiota during severe COVID-19.

The human microbiome plays a vital role in maintaining human homeostasis, acting as a key regulator of host immunity and defense mechanisms. However, dysbiotic microbial communities may cause disruption of the symbiotic relationship between the host and the local microbiota, leading to the pathogenesis of various diseases, including viral infections and cancers. One of the most common infectious agents causing cancer is the human papilloma virus (HPV), which accounts for more than 90% of cervical cancers. In most cases, the host immune system is activated and clears HPV, whereas in some cases, the infection persists and can lead to precancerous lesions. Over the last two decades, the advent of next-generation sequencing (NGS) technology and bioinformatics has allowed a thorough and in-depth analysis of the microbial composition in various anatomical niches, allowing researchers to unveil the interactions and the underlying mechanisms through which the human microbiota could affect HPV infection establishment, persistence, and progression. Accordingly, the present narrative review aims to shed light on our understanding of the role of the human microbiome in the context of HPV infection and its progression, mainly to cervical cancer. Furthermore, we explore the mechanisms by which the composition and balance of microbial communities exert potential pathogenic or protective effects, leading to either HPV persistence and disease outcomes or clearance. Special interest is given to how the microbiome can modulate host immunity to HPV infection. Lastly, we summarize the latest findings on the therapeutic efficacy of probiotics and prebiotics in preventing and/or treating HPV infections and the potential of vaginal microbiota transplantation while highlighting the significance of personalized medicine approaches emerging from NGS-based microbiome profiling and artificial intelligence (AI) for the optimal management of HPV-related diseases.

The oral cavity is the main gateway for the entry of C. difficile spores to the digestive tract. In conditions of poor oral hygiene and periodontal diseases, the dysbiotic oral microbiota may be a reservoir for several human pathogens. Here, we explored the prevalence of C. difficile in the oral microbiota of patients with severe periodontitis by the molecular detection of species specific genes.

Subgingival biofilm, saliva and/or feces from 659 patients with gingivitis, periodontitis and no periodontal diseases were screened for the tpi and toxin A/B genes specific for C. difficile by multiplex PCR. Differences among groups were sought by the Chi-square test.

The overall frequency of C. difficile tpi gene was 29 %, with a high detection of tcdB gene (44.8 %). Patients with periodontitis showed a greater prevalence of this gene in the biofilm than individuals with gingivitis and periodontal health (p = 0.001), particularly at more severe stages of disease (p < 0.05). No toxin genes were detected in feces or biofilm from healthy patients, whereas >70 % of the biofilm from patients with periodontal diseases were positive for these genes (p < 0.001). Detection of C. difficile tpi gene in oral/fecal samples correlated with periodontal inflammation (p < 0.05). A modest intra-individual agreement between tpi gene detection in feces and saliva was found within periodontitis patients (Kappa = 0.314; p = 0.003).

The high frequency of the C. difficile specific genes tpi and tcdB in the dysbiotic subgingival biofilm of advanced periodontitis could support the presence of the bacterium in this niche.

The lack of dental travel health care has been deplored for some time. Travel medicine's remit is to prepare people for travel. People travel with their mouth firmly in their body, yet the mouth's wellbeing does not rate a mention. This article represents the first exploration of a range of topics relevant to an until now neglected, yet potentially highly important, area of health care. A range of dental mishaps can occur while away from home, from simple toothache to accidents, serious emergencies, or restoration failures. Other problems originate in unwise behaviour, including holiday-inspired body modifications.Unless there is pain, teeth are typically not thought about much. However, examining the practical side of dental hygiene during travels, several overlooked and perhaps surprising topics emerge that - through the travel lens - take on a different and important role: the oral microbiome, toothbrush hygiene, the toilet plume, and traveller diarrhoea. Based on this discussion, recommendations are made for clinical practice, education, and further research.The historical chasm between dentistry and medicine, despite long-standing calls for change, does not seem to go away and impairs holistic high quality travel health care. Travel medicine can bypass this unproductive division. It has the unique opportunity to be the first medical specialty cooperating closely with dentists to bridge this gap by providing quality travel health care to travellers with all their body parts attached.

The metabolome of COVID-19 patients has been studied sparsely, with most research focusing on a limited number of plasma metabolites or small cohorts. This is the first study to test saliva metabolites in COVID-19 patients in a comprehensive way, revealing patterns significantly linked to disease and severity, highlighting saliva's potential as a non-invasive tool for pathogenesis or diagnostic studies.

We included 30 asymptomatic subjects with no prior COVID-19 infection or vaccination, 102 patients with mild SARS-CoV-2 infection, and 61 hospitalized patients with confirmed SARS-CoV-2 status. Saliva samples were analyzed using hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS/MS) in positive and negative ionization modes.

Significant differences in metabolites were identified in COVID-19 patients, with distinct patterns associated with disease severity. Dipeptides such as Val-Glu and Met-Gln were highly elevated in moderate cases, suggesting specific protease activity related to SARS-CoV-2. Acetylated amino acids like N-acetylserine and N-acetylhistidine increased in severe cases. Bacterial metabolites, including muramic acid and indole-3-carboxaldehyde, were higher in mild-moderate cases, indicating that oral microbiota differs according to disease severity. In severe cases, polyamines and organ-damage-related metabolites, such as N-acetylspermine and 3-methylcytidine, were significantly increased. Interestingly, most metabolites that were reduced in moderate cases were elevated in severe cases.

Saliva metabolomics offers insightful information that is potentially useful in studying COVID-19 severity and for diagnosis.

Developing biomaterials capable of promoting bone regeneration in bacteria-infected sites is of utmost urgency for periodontal disease therapies. Here we produce a hybrid hydrogel by integrating CuS nanoparticles (CuSNPs), which could kill bacteria through photothermal therapy (PTT) triggered by a near infrared (NIR) light, and a gelatin methacryloyl (GelMA) hydrogel, which is injectable and biocompatible. Specifically, CuSNPs were precipitated by chitosan (CS) firstly, then grafted with methacrylic anhydride (MA) to form CuSNP@CS-MA, which was photo-crosslinked with GelMA to synthesize hybrid hydrogels (GelMA/CuSNP). The hybrid hydrogels exhibited a broad-spectrum antibacterial property that could be spatiotemprorally manipulated through applying a NIR light. Their mechanical properties were adjustable by controlling the concentration of CuSNPs, enabling the hydrogels to become more adapted to the oral diseases. Meanwhile, the hybrid hydrogels showed good cytocompatibility in vitro and improved hemostasis in vivo. Moreover, they accelerated alveolar osteogenesis and vascular genesis, successfully treating periodontis in four weeks in a rat model. GelMA/CuSNP hydrogels showed a broad-spectrum sterilization ability via PTT in vitro and outstanding antibacterial property in vivo, suggesting that the hybrid hydrogels could function in the challenging, bacteria-rich, oral environment. Such injectable hybrid hydrogels, capable of achieving both facilitated osteogenesis and NIR-inducible sterilization, represent a new biomaterial for treating periodontitis.

Oral cavity dysbiosis is associated with numerous inflammatory diseases, including diabetes, inflammatory bowel diseases, and periodontal disease. Changes in the oral microenvironment lead to bidirectional interactions between pathogens and individual host systems, which may induce systemic inflammation. There is increasing evidence linking the condition of the oral cavity with the most common causes of female infertility, such as polycystic ovary syndrome and endometriosis, as well as gestational complications, e.g., low birth weight, preterm delivery, and miscarriages. This review highlights the composition of the female oral microbiome in relation to infertility-related disorders, such as endometriosis and polycystic ovary syndrome, and provides a comprehensive overview of the current state of knowledge on the relationship between a dysbiotic oral microbiome, pregnancy, and its impact on the female reproductive tract.

Orofacial pain (OFP) includes chronic pain conditions categorized into musculoskeletal (MS), neurovascular (NV), and neuropathic (NP) pain types, encompassing temporomandibular disorders (TMD), migraines, trigeminal neuralgia (TN), post-traumatic neuropathies, and burning mouth syndrome (BMS). These conditions significantly affect quality of life; yet, their underlying metabolic disruptions remain inadequately explored. Salivary metabolomics provides a non-invasive method to investigate biochemical alterations associated with OFP subtypes. This study aimed to identify pain-specific salivary metabolites across chronic OFP types and examine their correlations with clinical characteristics. Saliva samples from 63 OFP patients (TMD, migraines, TN, post-traumatic neuropathies, BMS) and 37 pain-free controls were analyzed using liquid chromatography-mass spectrometry (LC-MS) targeting 28 metabolites linked to pain. Statistical analyses determined significant metabolite changes and associations with pain subtypes and patient characteristics. Among the 28 analyzed metabolites, 18 showed significant differences between OFP patients and controls. Key amino acids, including DL-glutamic acid, DL-aspartic acid, DL-citrulline, spermidine, and DL-ornithine, were significantly elevated in MS, NV, and NP pain types compared to controls. Additionally, DL-glutamine, DL-valine, and DL-phenylalanine were distinctively elevated in TMD and migraine patients. BMS displayed fewer alterations, with significantly lower levels of DL-proline, DL-tryptophan, DL-glutamic acid, DL-asparagine, and DL-aspartic acid compared to other pain types but elevated spermidine levels relative to controls. Salivary metabolomics revealed distinct metabolic alterations in OFP subtypes, providing insights into potential biomarkers for diagnosis and monitoring. These findings offer a foundation for personalized approaches in OFP management, although further research is required to validate and expand these results.

The oral microbiome plays an important role in the development and progression of periodontal disease. The purpose of this study was to compare microbial profiles of oral cavities in good health, with gingivitis, and in a state of periodontitis, and to identify novel pathogens involved in periodontal diseases.

One hundred and two participants, including 33 healthy controls, 41 patients with gingivitis, and 28 patients with periodontitis, were included in this cross-sectional study. Salivary oral microbiomes were investigated using 16S rRNA metagenomic sequencing, and the microbial profiles of each group were compared using age- and sex-adjusted general linear models.

The abundance of amplicon sequence variants and Chao1 diversity were significantly elevated in the gingivitis and periodontitis groups relative to healthy controls (p = 0.046). Based on linear discriminant analysis (LDA) scores (>2), Tenericutes, Mollicutes, Mycoplasmatales, Mycoplasmataceae, Mycoplasma, Bacteroidaceae, and Phocaeicola were significantly enriched in the gingivitis group, and Synergistetes, Synergistia, Synergistales, Synergistaceae, Fretibacterium, Sinanaerobacter, and Filifactor were enriched in the periodontitis group. The relative abundances of Fretibacterium fastidiosum, Sinanaerobacter chloroacetimidivorans, and Filifactor alocis (q = 0.008, all bacteria) were highest in the periodontitis group and lowest in the control group. The relative abundance of Treponema denticola was significantly elevated in the periodontitis group compared to the other two groups (q = 0.024).

Oral microbiomes differed between groups. T. denticola, F. fastidiosum, S. chloroacetimidivorans and F. alocis were significantly more abundant in the periodontitis group than in the control group. Additionally, the abundance of T. denticola and F. fastidiosum in the periodontitis group was significantly different from that in the gingivitis group.

Porphyromonas gingivalis, a key pathogen in periodontal, plays a critical role in systemic pathologiesdiseases by evading host defence mechanisms and invading periodontal tissues. Targeting its virulence mechanisms and overcoming drug resistance are essential steps toward effective therapeutic development. In this study, we focused on the Carbonic Anhydrase (CA, EC: 4.2.1.1) encoded by P. gingivalis as a potential drug target. We determined the crystal structure of PgiCA γ at a resolution of 2.4 Å and conducted kinetic characterization. The structure revealed that active PgiCA γ forms a trimer, with each monomer comprising a left-handed β-helix capped by a C-terminal α-helix and coordinated to a catalytic zinc ion through three histidine residues. Interestingly, one monomer displayed an atypical α-helix conformation, likely due to close interactions with neighbouring trimers within the crystal lattice (a probable crystallographic artefact). These findings provide new insights into the structural and functional properties of PgiCA γ, emphasizing its potential as a target for the development of novel anti-virulence therapies against P. gingivalis.