The influence of microbiota on the development and course of inflammatory diseases of periodontal tissues

Comprehensive Analysis of Orthodontic Treatment Effects on the Oral Microbiome, Metabolome, and Associated Health Indicators

INTRODUCTION AND AIMS

Effects of orthodontic treatments on oral health, particularly on the microbiome and metabolome, are not well understood, and this study aims to clarify these influences using multi-omics approaches.

METHODS

We used 16SrRNA sequencing to analyze oral microbiota and untargeted metabolomics for metabolic profiling, comparing clear aligners (CAs) and fixed appliances (FAs) in healthy and unhealthy oral environments.

RESULTS

We found CAs significantly improve oral health markers-including reduced plaque accumulation, enamel demineralization, microbiome alpha diversity, and microbial heterogeneity, especially in unhealthy oral environments. Orthodontic treatment type and overall oral health status significantly altered the oral microbiota structure and metabolite composition. Notably, the effect of orthodontic methods was more pronounced on metabolome than on microbiome. There's a strong link between changes in oral microbiome, health status, and hygiene habits. For example, Prevotella and Treponema were linked to poor oral health indicators, whereas Rothia, Granulicatella, and Streptococcus were associated with good oral hygiene indicators. Machine learning analysis identified 13 key metabolites, including cholylarginine, alpha-CEHC glucuronide, 2-hydroxypentanoic acid, Cer (d17:1/6 keto-PGF1alpha), and LysoPE (15:0/0:0), which were associated with inflammatory responses and served as predictive markers for poor oral health. These metabolites were closely correlated with specific microbial species enriched in oral environment, including Rothia, Prevotella, and Anaeroglobus, suggesting their potential as biomarkers for oral health monitoring. KEGG enrichment revealed differential metabolites were significantly enriched in alkaloid biosynthesis pathways, particularly map01064, which is crucial for polyamine synthesis related to bacterial activities.

CONCLUSION

CAs significantly improve oral health markers, particularly affecting the metabolome more than the microbiome, with key metabolites and microbial species serving as potential biomarkers for oral health monitoring.

CLINICAL RELEVANCE

This study provides comprehensive insights into interactions among orthodontic treatments, oral health status, microbial, and metabolic dynamics, offering foundation for developing personalized strategies in oral health management and orthodontic care.

Forecasting the development of antimicrobial resistance of S. aureus

Today, about 15.0% of odontogenic pathology is caused by Staphylococcus aureus (S. aureus). The aim of the study was to predict the development of antimicrobial resistance of S. aureus based on retrospective data.

Methods

A total of 425 patients undergoing treatment for odontogenic infectious diseases of the facial area during 2019-2023 were involved in the study. The object of the study was 106 clinical isolates of S. aureus that were isolated and identified from patients. Determining the sensitivity of the obtained isolates to antimicrobial drugs was carried out using Vitek antimicrobial susceptibility testing (Biomerioux, France) and analyzed according to the breackpoint tables of the EUCAST. Prediction of the development of antimicrobial resistance of S. aureus to various antibiotics was carried out on the basis of the received sensitivity data of the studied isolates in 2019-2023 using the exponential smoothing method.

Results

The antimicrobial resistance of S. aureus isolates to various antibiotics changed annually during 2019-2023. The level of resistance of S. aureus isolates to benzylpenicillin wavered between 40%-50% from 2019 to 2023 with the trend of an 18.0% increase over the next five years. A uniform plateau of antimicrobial resistance of S. aureus to cefoxitin is predicted at the level of 32.0% during 2024-2028. We recorded the highest portions of S. aureus resistant to norfloxacin (33.3%) and ciprofloxacin (16.7%) in 2023 with prediction of its increasing in the next five years within the range of 20.0%. It was established that S. aureus may reach 100.0% resistance to gentamicin in 2027. According to exponential smoothing, the level of S. aureus resistance to amikacin will increase by 22.7% over the next five-year period. Moreover, representatives of this species of bacteria can develop complete (100.0%) resistance to tetracycline as early as 2027.

Conclusions

Mathematical prediction of the development of antimicrobial sensitivity of S. aureus isolates showed a high probability of its development to antibiotics of all groups in the next five years.

Extracellular vesicle production by oral bacteria related to dental caries and periodontal disease: role in microbe-host and interspecies interactions

Extracellular vesicles (EVs) are cell membrane-derived structures between 20-400 nm in size. In bacteria, EVs play a crucial role in molecule secretion, cell wall biogenesis, cell-cell communication, biofilm development, and host-pathogen interactions. Despite these increasing reports of bacterial-derived vesicles, there remains a limited number of studies that summarize oral bacterial EVs, their cargo, and their main biological functions. Therefore, the aim of this review is to present the latest research on oral bacteria-derived EVs and how they can modulate various physiological and pathological processes in the oral cavity, including the pathogenesis of highly relevant diseases such as dental caries and periodontitis and their systemic complications. Overall, caries-associated bacteria (such as Streptococcus mutans) as well as periodontal pathogens (including the red complex pathogens Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) have all been shown to produce EVs that carry an array of virulent factors and molecules involved in biofilm and immune modulation, bacterial adhesion, and extracellular matrix degradation. As bacterial EV production is strongly impacted by genotypic and environmental variations, the inhibition of EV genesis and secretion remains a key potential future approach against oral diseases.

Evaluation of the Antimicrobial Efficacy of Ethanolic and Aqueous Extracts of Licorice (Glycyrrhiza glabra) Against a Periodontal Pathogen: An In Vitro Study

BACKGROUND

Periodontal disease is a major contributing factor to tooth loss and can significantly impact overall health. Traditional periodontal therapy typically involves mechanical debridement to remove plaque and calculus, along with the use of antimicrobial agents to reduce bacterial load. Licorice (Glycyrrhiza glabra) has a long history of use in traditional medicine for treating various ailments since it contains glycyrrhizin, glabridin, liquiritin, and flavonoids, which possess anti-inflammatory, antioxidant, and antimicrobial activities. Hence, licorice can be considered a viable alternative for managing periodontal inflammation.

AIM

The objective of this study is to conduct a comparative evaluation of the antimicrobial efficacy of ethanolic and aqueous extracts of licorice (Glycyrrhiza glabra) against a key periodontal pathogen, Prevotella intermedia (P. intermedia) Methodology: In this study, aqueous and ethanolic preparation of licorice was done, and the antimicrobial effect of these extracts against P. intermediawas tested by evaluating the minimum inhibitory concentration (MIC). The gold standard chemical plaque control agent chlorhexidine was used as a control.  Result: Results of the present study showed that licorice extract has antimicrobial activity against P. intermedia. The MIC of aqueous and ethanolic licorice root extracts against P. intermedia was established at 0.8% and 0.1%, respectively. When the aqueous and ethanolic extracts were compared, the ethanolic extract of licorice showed significantly more antimicrobial properties than the aqueous extract.

CONCLUSION

Ethanolic extract of licorice possesses highly significant antibacterial activity against P. intermedia; hence, it can be used as an alternative to chlorhexidine mouthwash.

Current progresses and challenges for microbiome research in human health: a perspective

It is becoming increasingly clear that the human microbiota, also known as "the hidden organ", possesses a pivotal role in numerous processes involved in maintaining the physiological functions of the host, such as nutrient extraction, biosynthesis of bioactive molecules, interplay with the immune, endocrine, and nervous systems, as well as resistance to the colonization of potential invading pathogens. In the last decade, the development of metagenomic approaches based on the sequencing of the bacterial 16s rRNA gene via Next Generation Sequencing, followed by whole genome sequencing via third generation sequencing technologies, has been one of the great advances in molecular biology, allowing a better profiling of the human microbiota composition and, hence, a deeper understanding of the importance of microbiota in the etiopathogenesis of different pathologies. In this scenario, it is of the utmost importance to comprehensively characterize the human microbiota in relation to disease pathogenesis, in order to develop novel potential treatment or preventive strategies by manipulating the microbiota. Therefore, this perspective will focus on the progress, challenges, and promises of the current and future technological approaches for microbiome profiling and analysis.

Enamel Matrix Derivative Suppresses Chemokine Expression in Oral Epithelial Cells

Epithelial cells in periodontitis patients increasingly express chemokines, suggesting their active involvement in the inflammatory process. Enamel matrix derivative (EMD) is an extract of porcine fetal tooth germs clinically applied to support the regrowth of periodontal tissues. Periodontal regeneration might benefit from the potential anti-inflammatory activity of EMD for epithelial cells. Our aim was, therefore, to set up a bioassay where chemokine expression is initiated in the HSC2 oral squamous carcinoma cell line and then test EMD for its capacity to lower the inflammatory response. To establish the bioassay, HSC2 cells being exposed to TNFα and LPS from E. coli (Escherichia coli) or P. gingivalis (Porphyromonas gingivalis) were subjected to RNAseq. Here, TNFα but not LPS caused a robust increase of chemokines, including CXCL1, CXCL2, CXCL8, CCL5, and CCL20 in HSC2 cells. Polymerase chain reaction confirmed the increased expression of the respective chemokines in cells exposed to TNFα and IL-1β. Under these conditions, EMD reduced the expression of all chemokines at the transcriptional level and CXCL8 by immunoassay. The TGF-β receptor type I kinase-inhibitor SB431542 reversed the anti-inflammatory activity. Moreover, EMD-activated TGF-β-canonical signaling was visualized by phosphorylation of smad3 and nuclear translocation of smad2/3 in HSC2 cells and blocked by SB431542. This observation was confirmed with primary oral epithelial cells where EMD significantly lowered the SB431542-dependent expression of CXCL8. In summary, our findings suggest that TGF-β signaling mediates the effects of EMD to lower the forced expression of chemokines in oral epithelial cells.