Mobile microbiome: oral bacteria in extra-oral infections and inflammation

Gingival enlargement induced by cyclosporine in Medullary aplasia: A case report

BACKGROUND

Cyclosporine is an immunosuppressive agent used effectively for treatment of a rare haematological disorder known as medullary aplasia. This drug prevents several side effects, including gingival enlargement (GE) which compromises aesthetics, phonetics and chewing, and also predisposes patients to periodontitis.

CASE SUMMARY

This clinical case reports a 41-year-old woman who presented with cyclosporine-induced GE with underlying periodontitis and medullary aplasia. The management of the disease was approached through multidisciplinary strategy which allowed for accurate diagnosis and a strategic treatment based on the systemic condition and severity of oral pathology. The diagnosis was confirmed through histopathological analysis. The treatment was carried out in phases: Initial (oral hygiene motivation, mechanical supragingival plaque control, and non-surgical therapy); systemic treatment, corrective treatment, and maintenance.

CONCLUSION

Multidisciplinary management of cyclosporine-induced GE and medullary aplasia allows for correct diagnosis and effective treatment of this pathological expression through a phased therapeutic approach.

Identification of Fusobacterium Species Using Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight Mass Spectrometry by Updating ASTA CoreDB

PURPOSE

Fusobacterium species can cause infections, and associations with cancer are being increasingly reported. As their clinical significance differs, accurate identification of individual species is important. However, matrix-assisted laser desorption/ionization-time of flight mass spectrometry has not been found to be effective in identifying Fusobacterium species in previous studies. In this study, we aimed to improve the accuracy and efficacy of identifying Fusobacterium species in clinical laboratories.

MATERIALS AND METHODS

In total, 229 Fusobacterium isolates were included in this study. All isolates were identified at the species level based on nucleotide sequences of the 16S ribosomal RNA gene and/or DNA-dependent RNA polymerase β-subunit gene (rpoB). Where necessary, isolates were identified based on whole genome sequences. Among them, 47 isolates were used for updating the ASTA database, and 182 isolates were used for the validation of Fusobacterium spp. identification.

RESULTS

Fusobacterium isolates used for validation (182/182) were correctly identified at the genus level, and most (180/182) were correctly identified at the species level using the ASTA MicroIDSys system. Most of the F. nucleatum isolates (74/75) were correctly identified at the subspecies level.

CONCLUSION

The updated ASTA MicroIDSys system can identify nine species of Fusobacterium and four subspecies of F. nucleatum in good agreement. This tool can be routinely used in clinical microbiology laboratories to identify Fusobacterium species and serve as a springboard for future research.

Prevalence of Microorganisms in Atherosclerotic Plaques of Coronary Arteries: A Systematic Review and Meta-Analysis

Background

In this systematic review and meta-analysis, the existence of pathogens in atherosclerotic plaques of coronary arteries was investigated in coronary arteries diseases (CAD) patients.

Methods

This study was designed and implemented up to 31 August 2020. The findings present according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) checklist. Two independent reviewers (I.RJ and S.H) performed a comprehensive search on four different English databases including PubMed, ISI, Scopus, and Embase. In order to assess the quality of the articles, a checklist prepared by The Joanna Briggs Institute (JBI) was used.

Results

Finally, 44 studies were selected. The prevalence of different microorganisms in coronary arteries were as follows: Aggregatibacter actinomycetemcomitans (46.2%), Campylobacter rectus (43.0%), Chlamydia pneumonia (42.8%), Cytomegalovirus (29.1%), Helicobacter pylori (18.9%), Herpes simplex virus type 1 (5.9%), Porphyromonas gingivalis (42.6%), Prevotella intermedia (47.6%), Tannerella forsythia (43.7%), and Treponema denticola (32.9%).

Conclusion

Based on the result of this meta-analysis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans are the most common microorganisms in atherosclerotic plaques of coronary arteries and may have an important role in the development of atherosclerosis.

Elevated dietary carbohydrate and glycemic intake associate with an altered oral microbial ecosystem in two large U.S. cohorts

The human oral microbiome is associated with chronic diseases including cancer. However, our understanding of its relationship with diet is limited. We assessed the associations between carbohydrate and glycemic index (GI) with oral microbiome composition in 834 non-diabetic subjects from the NCI-PLCO and ACS-CPSII cohorts. The oral microbiome was characterized using 16Sv3-4 rRNA-sequencing from oral mouthwash samples. Daily carbohydrate and GI were assessed from food frequency questionnaires. We used linear regression, permutational MANOVA, and negative binomial Generalized Linear Models (GLM) to test associations of diet with α- and β-diversity and taxon abundance (adjusting for age, sex, cohort, BMI, smoking, caloric intake, and alcohol). A q-value (FDR-adjusted P-value) of <0.05 was considered significant. Oral bacterial α-diversity trended higher in participants in the highest quintiles of carbohydrate intake, with marginally increased richness and Shannon diversity (p-trend=0.06 and 0.07). Greater carbohydrate intake was associated with greater abundance of class Fusobacteriia (q=0.02) and genus Leptotrichia (q=0.01) and with lesser abundance of an Actinomyces OTU (q=4.7E-04). Higher GI was significantly related to greater abundance of genus Gemella (q=0.001). This large, nationwide study provides evidence that diets high in carbohydrates and GI may influence the oral microbiome.

The systemic oral health connection: Biofilms

Frequently, periodontal health and it's associated oral biofilm has not been addressed in those patients who have systemic health issues, especially those who are not responding to medical treatment via their physician. Oral biofilm may be present in the periodontal sulcus in the absence of clinical disease of periodontal disease (bleeding on probing, gingival inflammation) and periodontal reaction is dependent on the patient's immune response to the associated bacterial and their byproducts. Increasing evidence has been emerging the past decade connecting oral biofilm with systemic conditions, either initiating them or complicating those medical conditions. The patient's health needs to be thought of as a whole-body system with connections that may originate in the oral cavity and have distant affects throughout the body. To maximize total health, a coordination in healthcare needs to be a symbiosis between the physician and dentist to eliminate the oral biofilm and aid in prevention of systemic disease or minimize those effects to improve the patient's overall health and quality of life. Various areas of systemic health have been associated with the bacteria and their byproducts in the oral biofilm. Those include cardiovascular disease, chronic kidney disease, diabetes, pulmonary disease, prostate cancer, colon cancer, pancreatic cancer, pre-term pregnancy, erectile dysfunction Alzheimer's disease and Rheumatoid arthritis. This article will discuss oral biofilm, its affects systemically and review the medical conditions associated with the oral systemic connection with an extensive review of the literature.

The oral microbiota and cardiometabolic health: A comprehensive review and emerging insights

There is mounting evidence demonstrating that oral dysbiosis causes periodontal disease and promotes the development of cardiovascular disease. The advancement of omics techniques has driven the optimization of oral microbiota species analysis and has provided a deeper understanding of oral pathogenic bacteria. A bi-directional relationship exists between the oral microbiota and the host, and oral-gut microbiota transfer is known to alter the composition of the gut microbiota and may cause local metabolic disorders. Furthermore, cardiovascular health can also be highly affected by oral microbiota functions and metabolites, including short-chain fatty acids (SCFAs), nitric oxide (NO), hydrogen sulfide (H2S), and some lipid metabolites. Studies have found that trimethylamine oxide (TMAO) may have adverse effects on cardiovascular health, whereas SCFAs, NO, and H2S have cardioprotective effects. SCFAs and H2S exert varying oral and cardiovascular effects, however reports on this specific topic remain controversial. Previous evidences are accustomed to summarizing the functions of oral microbiota in the context of periodontitis. The direct relationship between oral microbiota and cardiovascular diseases is insufficient. By systematically summarizing the methods associated with oral microbiota transplantation (OMT), this review facilitates an investigation into the causal links between oral microbiota and cardiovascular disease. The concomitant development of omics, bioinformatics, bacterial culture techniques, and microbiota transplantation techniques is required to gain a deeper understanding of the relationship between oral microbiota and cardiovascular disease occurrence.

Characterizing the supragingival microbiome of healthy pregnant women

The ecological characteristics and changes of the supragingival plaque microbial community during pregnancy are poorly understood. This study compared the microbial community characteristics of supragingival plaque in pregnant and non-pregnant women, with the aim of identifying specific microbial lineages and genera that may be associated with pregnancy. Thirty pregnant women were randomly selected from the First Affiliated Hospital of Xinjiang Medical University and divided into groups based on pregnancy trimester: first trimester (group P1, n=10, ≤12 weeks), second trimester (group P2, n=10, 13–27 weeks), and third trimester (group P3, n=10, 28–40 weeks). Ten healthy non-pregnant women (group N) were enrolled as the control group. Supragingival plaque samples of all subjects were collected and oral microbial composition was surveyed using a 16S rRNA gene sequencing approach. Statistical analysis was performed using a nonparametric test. The Chao 1 index of P3 was significantly lower compared with that of N, P1, and P2 (P&lt;0.05). The Simpson indices of P2 and P3 were significantly higher than that of N (P&lt;0.05). The Shannon index of P2 was significantly higher compared with that of N (P&lt;0.05). Principal coordinate analysis (PCoA) showed different clustering according to the pregnancy status. Linear discriminant analysis effect size (LEfSe) revealed that the microbial species in group N that were significantly different from those of other groups were concentrated in the genus Neisseria. Species in P1 that were significantly different from those of other groups were concentrated in the genus Tannerella, while those in P2 and P3 were concentrated in the genus Leptotrichia. A total of 172 functional pathways were predicted for the bacterial communities in this study using PICRUSt2. Principal Component Analysis (PCA) showed that most predicted functional pathways clustered together in N and P1 and in P2 and P3. LEfSe analysis revealed that 11 pathways played a discriminatory role in the four groups. This work suggests a potential role of pregnancy in the formation of supragingival plaque microbiota and indicates that physiological changes during pregnancy may convert supragingival plaque into entities that could cause harm, which may be a risk factor for maternal health. Furthermore, findings from the study provide a basis for etiological studies of pregnancy-associated oral ecological disorders.

Exploring the Mechanisms and Association between Oral Microflora and Systemic Diseases

The scope of dentistry is ever-changing and dynamic in all fields of dentistry including periodontal health and disease. Recent studies show that oral health and systemic health are interdependent, particularly in the way that poor oral hygiene and periodontal health affect the systemic health of an individual and vice versa. Periodontal diseases are multifactorial in nature in which the role of bacterial infections is inevitable. Furthermore, high-throughput sequencing technologies have shed light on the dysregulation of the growth of oral microbial flora and their environment, including those that are associated with periodontitis and other oral and non-oral diseases. Under such circumstances, it becomes important to explore oral microbiota and understand the effects of periodontal pathogens in the pathogenesis of systemic diseases. In addition, it may strengthen our view that a better understanding of oral microbial flora and proper examination of the oral cavity may aid in the early diagnosis and possible treatment of systemic diseases and conditions. This will eventually lead to providing better care to our patients. Therefore, in this research, we attempt to outline the periodontal pathophysiology along with the role of periodontal pathogens in some commonly encountered systemic conditions.

Oral Microbiota and Tumor-A New Perspective of Tumor Pathogenesis

Microorganisms have long been known to play key roles in the initiation and development of tumors. The oral microbiota and tumorigenesis have been linked in epidemiological research relating to molecular pathology. Notably, some bacteria can impact distal tumors by their gastrointestinal or blood-borne transmission under pathological circumstances. Certain bacteria drive tumorigenesis and progression through direct or indirect immune system actions. This review systemically discusses the recent advances in the field of oral microecology and tumor, including the oncogenic role of oral microbial abnormalities and various potential carcinogenesis mechanisms (excessive inflammatory response, host immunosuppression, anti-apoptotic activity, and carcinogen secretion) to introduce future directions for effective tumor prevention.

The interplay between oral microbes and immune responses

Oral microbes play a critical role in maintaining oral homeostasis. Microbial dysbiosis promotes disease pathogenesis through several mechanisms. Recent studies have revealed that microbial imbalance and sustained inflammation are involved in disease progression. The adverse interaction triggered by a host immune response to microorganisms can lead to oral and systemic diseases. Here, we reviewed how oral microbes communicate with hosts during the development of local and distant inflammation. Elucidation of these processes may reveal future directions in this field and the potential targets of novel biological therapies for oral and systemic diseases.

The oral microbiota and its role in carcinogenesis

Despite decades of research, cancer continues to be a major global health concern. In recent years, the role played by microorganisms in the development and progression of cancer has come under increased scrutiny. The aim of the present review is to highlight the main associations between members of the human oral microbiota and various cancers. The PubMed database was searched for available literature to outline the current state of understanding regarding the role of the oral microbiota and a variety of human cancers. Oral squamous cell carcinoma (OSCC) is associated with carriage of a number of oral bacteria (e.g., Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sp.), certain viruses (e.g., human papilloma virus, human herpes virus 8, herpes simplex virus 1 and Epstein-Barr virus) and yeast (Candida albicans). Moreover, members of the oral microbiota are associated with cancers of the esophagus, stomach, pancreas, colon/rectum and lung. Furthermore, the present review outlines a number of the carcinogenic mechanisms underlying the presented microbial associations with cancer. Such information may one day help clinicians to diagnose neoplastic diseases at earlier stages and prescribe treatments that take into account the possible microbial nature of carcinogenesis.

Proton Pumping ATPases: Rotational Catalysis, Physiological Roles in Oral Pathogenic Bacteria, and Inhibitors

Proton pumping ATPases, both F-type and V/A-type ATPases, generate ATP using electrochemical energy or pump protons/sodium ions by hydrolyzing ATP. The enzymatic reaction and proton transport are coupled through subunit rotation, and this unique rotational mechanism (rotational catalysis) has been intensively studied. Single-molecule and thermodynamic analyses have revealed the detailed rotational mechanism, including the catalytically inhibited state and the roles of subunit interactions. In mammals, F- and V-ATPases are involved in ATP synthesis and organelle acidification, respectively. Most bacteria, including anaerobes, have F- and/or A-ATPases in the inner membrane. However, these ATPases are not believed to be essential in anaerobic bacteria since anaerobes generate sufficient ATP without oxidative phosphorylation. Recent studies suggest that F- and A-ATPases perform indispensable functions beyond ATP synthesis in oral pathogenic anaerobes; F-ATPase is involved in acid tolerance in Streptococcus mutans, and A-ATPase mediates nutrient import in Porphyromonas gingivalis. Consistently, inhibitors of oral bacterial F- and A-ATPases, such as phytopolyphenols and bedaquiline, strongly diminish growth and survival. Herein, we discuss rotational catalysis of bacterial F- and A-ATPases, and discuss their physiological roles, focusing on oral bacteria. We also review the effects of ATPase inhibitors on the growth and survival of oral pathogenic bacteria. The features of the catalytic mechanism and unique physiological roles in oral bacteria highlight the potential for proton pumping ATPases to serve as targets for oral antimicrobial agents.

Melatonin ameliorates lung cell inflammation and apoptosis caused by Klebsiella pneumoniae via AMP-activated protein kinase

Klebsiella pneumoniae is a Gram-negative bacterium and the causative agent of several life-threatening nosocomial infections, including pneumonia. K. pneumoniae induces acute lung injury and inflammation in humans that require immediate hospitalization and treatment. Therefore, attenuation of K. pneumoniae-induced inflammation is necessary for the survival of patients. This study investigated the mechanisms by which melatonin abrogated K. pneumoniae-induced inflammation and apoptosis of lung cell lines, HLF-1 and BEAS-2B. Our results showed that in vitro infection of HLF-1 and BEAS-2B cells by K. pneumoniae significantly induced inflammation and apoptosis increased elevated levels of IL-6, CXCL1, CXCL2, and caspase-9 mRNA. However, these effects were abrogated by melatonin treatment. Infection with K. pneumoniae significantly increased the expression of AMP-induced protein kinase (AMPK). Furthermore, AMPK silencing significantly abrogated the suppression of inflammation and apoptosis in melatonin-infected K. pneumoniae lung cells. Melatonin could alleviate K. pneumoniae infection-induced inflammation in three-dimensional lung spheroids. In conclusion, our study demonstrated that melatonin abrogated K. pneumoniae-induced inflammation and apoptosis in lung cells through AMPK. Our study demonstrated the potential of melatonin for therapy against K. pneumoniae infections including pneumonia.

Insight into the Relationship between Oral Microbiota and the Inflammatory Bowel Disease

Inflammatory bowel disease has been a growing concern of lots of people globally, including both adults and children. As a chronic inflammatory disease of the intestine, even though the etiology of inflammatory bowel disease is still unclear, the available evidence from clinic observations has suggested a close association with microorganisms. The oral microbiota possesses the characteristics of a large number and abundant species, second only to the intestinal microbiota in the human body; as a result, it successfully attracts the attention of researchers. The highly diverse commensal oral microbiota is not only a normal part of the oral cavity but also has a pronounced impact on the pathophysiology of general health. Numerous studies have shown the potential associations between the oral microbiota and inflammatory bowel disease. Inflammatory bowel disease can affect the composition of the oral microbiota and lead to a range of oral pathologies. In turn, there are a variety of oral microorganisms involved in the development and progression of inflammatory bowel disease, including Streptococcus spp., Fusobacterium nucleatum, Porphyromonas gingivalis, Campylobacter concisus, Klebsiella pneumoniae, Saccharibacteria (TM7), and Candida albicans. Based on the above analysis, the purpose of this review is to summarize this relationship of mutual influence and give further insight into the detection of flora as a target for the diagnosis and treatment of inflammatory bowel disease to open up a novel approach in future clinical practice.

Diversity of the gut, vaginal and oral microbiome among pregnant women in South Africa with and without pre-eclampsia

Background

Changes in microbial communities are a known characteristic of various inflammatory diseases and have been linked to adverse pregnancy outcomes, such as preterm birth. However, there is a paucity of information regarding the taxonomic composition and/or diversity of microbial communities in pre-eclampsia. The aim of this study was to determine the diversity of the gut, vaginal and oral microbiome in a cohort of South African pregnant women with and without pre-eclampsia. The diversity of the gut, vaginal and oral microbiome was determined by targeted next generation sequencing (NGS) of the V3 and V4 region of the 16S rRNA gene on the Illumina MiSeq platform.

Results

In this study population, pre-eclampsia was associated with a significantly higher alpha diversity (P = 0.0472; indicated by the Shannon index) in the vaginal microbiome accompanied with a significant reduction in Lactobacillus spp. (P = 0.0275), compared to normotensive pregnant women. Lactobacillus iners was identified as the predominant species of the vaginal microbiome in both cohorts. High inter-individual variation in alpha diversity was observed in the gut and oral microbiome in both cohorts. Although differences in the relative abundance of bacteria at all phylogenetic levels were observed, overall microbial composition of the gut, oral and vaginal microbiome was not significantly different in the pre-eclampsia cohort compared to the normotensive cohort.

Conclusion

Collectively, a reduction of Lactobacillus spp., and predominance of L. iners in pregnant women with pre-eclampsia could suggest an unstable vaginal microbiome that might predispose pregnant women to develop pre-eclampsia. The lack of significant structural changes in the gut, oral and vaginal microbiome does not suggest that the characterized communities play a role in pre-eclampsia, but could indicate a characteristic unique to the study population. The current study provided novel information on the diversity of the gut, oral and vaginal microbiome among pregnant women in South Africa with and without pre-eclampsia. The current study provides a baseline for further investigations on the potential role of microbial communities in pre-eclampsia.

A Commentary on the Potential Use of Oral Microbiome in Prediction, Diagnosis or Prognostics of a Distant Pathology

In health, the oral microbiome is in balance with its host. If this balance is lost, this symbiosis is replaced by dysbiotic microbial communities, which are thought to affect the rest of the body either directly or via metabolites or pro-inflammatory molecules. The association of oral microbiome with general health has led to attempts to use oral microbial biomarkers for the prediction, diagnosis or prognosis of distant pathologies such as colorectal carcinoma or pancreatic cancer. These attempts however have no chance to succeed if the complexity of the oral ecosystem and the interplay of environmental, behavioral and biological factors is not taken into account. Standardized, well-documented oral sample collection procedures together with detailed clinical oral examination and behavioral data are the prerequisites for the successful evaluation of the oral microbiome as a potential biomarker for distant pathologies.

Microbial Analysis of Umbilical Cord Blood Reveals Novel Pathogens Associated with Stillbirth and Early Preterm Birth

Stillbirths account for half of all perinatal mortality, but the underlying cause of a significant portion of the cases remains unknown. We set out to test the potential role and extent of microbial infection in stillbirth through a case-control analysis of fetal cord blood collected from the multisite Stillbirth Collaborative Research Network. Cases (n = 60) were defined as stillbirths at >20 weeks of gestation, and controls (n = 176) were live births. The bacterial presence, abundance, and composition were analyzed by endpoint PCR of full-length 16S rRNA and the V4 amplicon sequence variants (ASVs). The results demonstrate that bacterial prevalence and abundance were both significantly increased in stillbirth, even after adjusting for maternal age, race, body mass index, number of pregnancies, gestational age, and multiple gestations. Composition of bacterial communities in the cord blood also differed significantly. Using a group of 25 ASVs differentially abundant between the two groups, a Random Forest classification model achieved an accuracy score of 0.76 differentiating stillbirth and live birth, with Group B Streptococcus as the most enriched species in stillbirth. Positive PCR was also significantly associated with early preterm birth. A group of oral anaerobes, including Actinomyces, Campylobacter, Fusobacterium, Peptostreptococcus, Porphyromonas, and Prevotella, were enriched in live early preterm birth, suggesting possible oral origin of infection. Our ASV-based microbiome analysis revealed specific candidate pathogens associated with infections in stillbirth and early preterm birth. The cord blood microbial signatures may be markers of adverse pregnancy outcomes. Our study will help identify possible mechanism of infection and improve our ability to prevent stillbirth and early preterm birth.

Sonication versus the conventional method for evaluation of the dental microbiome: a prospective pilot study

Objectives

To investigate sonication as a new tool in microbiological probing of dental infections.

Methods

Comparison of a standard probing method: intraoperative swab, with sonication, and vortex of the removed tooth, was performed on 20 carious destructed teeth. Illumina high throughput sequencing of the 16S-rRNA-gene was used for assessing the microbial composition. Antibiotic susceptibility has been assigned based on known resistances of each detected species. Probing procedures were compared using Bland–Altmann-Test, and antibiotic susceptibility using the Friedmann-Test and alpha-adjusted post-hoc-analysis.

Results

In total, 60 samples were analysed: 20 intraoperative swabs, 20 vortex fluids, and 20 sonication fluids. Sonication fluid yielded the highest number of bacterial sequencing reads in all three procedures. Comparing the operational taxonomic units (OTUs) of the identified bacteria, significantly more OTUs were found in sonication fluid samples. Phylum and order abundances varied between the three procedures. Significantly more Actinomycetales have been found in sonication fluid samples compared to swab samples. The assigned resistance rates for the identified bacteria (1.79–31.23%) showed no differences between the tested probing procedures. The lowest resistance rates were found for amoxicillin + clavulanate (3.95%) and levofloxacin (3.40%), with the highest in amoxicillin (30.21%) and clindamycin (21.88%).

Conclusions

By using sonication on extracted teeth, it is possible to get a more comprehensive image of the residing microbial flora compared to the standard procedure. If sonication is not available, vortexing is a potential alternative. In immunocompromised patients, especially when actinomycosis is suspected, sonication should be considered for a more detailed microbiological evaluation of the potential disease-causing microbiome. Due to the high rates of antibiotic resistance, a more targeted antibiotic therapy is favourable. Levofloxacin should be considered as a first-line alternative to amoxicillin + clavulanate in patients with an allergy to penicillin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02374-0.

Is periodontal disease a risk indicator for urogenital cancer? A systematic review and meta-analysis of cohort studies

Objectives

The objective of the present work was to conduct a systematic review and meta-analysis to assess the association between periodontal disease (PD) and urogenital cancer (UC) risk.

Materials and methods

An electronic search in PubMed, EMBASE, the Cochrane Library, and Web of Science was conducted using MeSH terms to identify cohort studies published before May 17, 2022. Cohort studies examining the association between PD and UC risk were included. We used a random-effects model to summarize the effect sizes with 95% confidence intervals (CIs) of the included studies with PD as the indicator and UC as the outcome.

Results

Eleven cohort studies met the inclusion criteria. Our results suggest that PD patients increases the risk of UC by 1.24-fold (hazard ratio (HR), 1.24; 95% CI, 1.17-1.31; I², 22.4%). The strength of the sensitivity analysis and cumulative meta-analysis confirmed the reliability of the results.

Conclusion

We found that PD is a potential risk factor for UC. Our results indicate that along with the decrease in the incidence of PD,PD treatment may help prevent UC. We hope that our study will raise awareness of periodontal health, thereby reducing the incidence of UC.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021244405.

Metagenomic analysis reveals associations between salivary microbiota and body composition in early childhood

Several studies have shown that body mass index is strongly associated with differences in gut microbiota, but the relationship between body weight and oral microbiota is less clear especially in young children. We aimed to evaluate if there is an association between child growth and the saliva microbiome. We hypothesized that associations between growth and the saliva microbiome would be moderate, similarly to the association between growth and the gut microbiome. For 236 toddlers participating in the New Hampshire Birth Cohort Study, we characterized the association between multiple longitudinal anthropometric measures of body height, body weight and body mass. Body Mass Index (BMI) z-scores were calculated, and dual-energy x-ray absorptiometry (DXA) was used to estimate body composition. Shotgun metagenomic sequencing of saliva samples was performed to taxonomically and functionally profile the oral microbiome. We found that within-sample diversity was inversely related to body mass measurements while community composition was not associated. Although the magnitude of associations were small, some taxa were consistently associated with growth and modified by sex. Certain taxa were associated with decreased weight or growth (including Actinomyces odontolyticus and Prevotella melaninogenica) or increased growth (such as Streptococcus mitis and Corynebacterium matruchotii) across anthropometric measures. Further exploration of the functional significance of this relationship will enhance our understanding of the intersection between weight gain, microbiota, and energy metabolism and the potential role of these relationships on the onset of obesity-associated diseases in later life.

Pyroptosis may play a crucial role in modifications of the immune microenvironment in periodontitis

BACKGROUND AND OBJECTIVE

Published studies proved that both pyroptosis and periodontitis owned a substantial relationship with immunity, and recent research revealed a solid correlation between periodontitis and pyroptosis. While abundant findings have confirmed pyroptosis has a strong impact on the tumor microenvironment, the function of pyroptosis in influencing the periodontitis immune microenvironment remains poorly understood. Thus, we aimed to identify pyroptosis-related genes whose expression signature can well discriminate periodontitis from healthy controls and to comprehend the role of pyroptosis in the periodontitis immune microenvironment.

MATERIALS AND METHODS

The periodontitis-related datasets were acquired from the Gene Expression Omnibus (GEO) database. A series of bioinformatics analyses were conducted to investigate the underlying mechanism of pyroptosis in the periodontitis immune microenvironment. Infiltrating immunocytes, immunological reaction gene sets, and the human leukocyte antigen (HLA) gene were all investigated as potential linkages between periodontitis immune microenvironment and pyroptosis.

RESULTS

Twenty-one pyroptosis-related genes were dysregulated. A four-mRNA combined classification model was constructed, and the receiver operating characteristic (ROC) curve analysis demonstrated its prominent classification capabilities. Subsequently, the mRNA levels of the four hub markers (CYCS, CASP3, NOD2, CHMP4B) were validated by quantitative real-time PCR (qRT-PCR). The correlation coefficients between each hub gene and immune characteristics were calculated, and CASP3 exhibited the most significant correlations with the immune characteristics. Furthermore, distinct pyroptosis-related expression patterns were revealed, along with immunological features of each pattern. Afterward, we discovered 1868 pyroptosis phenotype-related genes, 134 of which were related to immunity. According to the functional enrichment analysis, these 134 genes were closely related to cytokine signaling in immune system, and defense response. Finally, a co-expression network was constructed via the 1868 gene expression profiles.

CONCLUSION

Four hub mRNAs (CYCS, CASP3, NOD2, and CHMP4B) formed a classification model and concomitant results revealed the crucial role of pyroptosis in the periodontitis immune microenvironment, providing fresh insights into the etiopathogenesis of periodontitis and potential immunotherapy.

Characterization of Bacterial Differences Induced by Cleft-Palate-Related Spatial Heterogeneity

Background: Cleft palate (CP) patients have a higher prevalence of oral and respiratory tract bacterial infections than the general population. Nevertheless, characteristics of bacterial differences induced by CP-related anatomical heterogeneity are unknown. Methods: In this study, we systematically described the characteristics of bacteria in the oral and nasal niches in healthy children, CP children, healthy adolescents, CP adolescents, and postoperative adolescents by 454-pyrosequencing technology (V3−V6) to determine bacterial differences induced by CP. Results: Due to the CP-induced variations in spatial structure, the early establishment of microecology in CP children was different from that in healthy children. Nasal bacterial composition showed greater changes than in the saliva. Moreover, such discrepancy also appeared in CP and postoperative adolescents who had even undergone surgery > 10 years previously. Interestingly, we found by Lefse analysis that part of bacterial biomarkers in the nasal cavity of CP subjects was common oral flora, suggesting bacterial translocation between the oral and nasal niches. Therefore, we defined the oral−nasal translocation bacteria as O-N bac. By comparing multiple groups, we took the intersection sets of O-N bacs selected from CP children, CP adolescents, and postoperative adolescents as TS O-N bacs with time−character, including Streptococcus, Gemella, Alloprevotella, Neisseria, Rothia, Actinomyces, and Veillonella. These bacteria were at the core of the nasal bacterial network in CP subjects, and some were related to infectious diseases. Conclusions: CP would lead to significant and long-term differences in oral and nasal flora. TS O-N bacs migrating from the oral to the nasal might be the key stone causing nasal flora dysbiosis in the CP patients.

Antifungal Susceptibility of Candida albicans Isolated from Tongue and Subgingival Biofilm of Periodontitis Patients

The subgingival biofilm, as the most complex microbial community, has been proven to be reservoir of Candida spp. The main concept of this study was to investigate if there is a difference between the sensitivity of Candida albicans (C. albicans) isolated from tongue and subgingival areas of periodontitis patients to antifungal agents. The aim of the study was to determine: (1) the distribution of different Candida species in the tongue and subgingival samples of periodontitis patients; (2) the susceptibility of Candida albicans strains from tongue and subgingival biofilm to the effects of commonly used antifungal agents: fluconazole, amphotericin B and itraconazole; (3) the correlation between the susceptibility of Candida albicans and clinical periodontal parameters. Tongue and subgingival biofilm samples of periodontitis subjects (N = 163) were examined. Susceptibility was tested when the same Candida species was isolated from both sites (17 subjects). Candida spp. were isolated in 23.3% of tongue and 21.5% of the subgingival samples. All isolates were susceptible to amphotericin B, while 64.71% of tongue and 52.94% of subgingival isolates were susceptible to fluconazole. A low frequency of itraconazole susceptibility was observed for tongue (17.64%) and subgingival isolates (11.76%). The correlations between full-mouth plaque score and Minimal Inhibitory Concentration (MIC) for tongue isolates were strongly positive for all antimycotics. Positive correlation was also observed between moderate periodontal destruction and MICs for tongue and subgingival isolates. The susceptibility of C. albicans to antifungals correlate with oral hygiene and moderate periodontal destruction. There is no difference in antifungal susceptibility between tongue and subgingival isolates.

Standardized studies of the oral microbiome: From technology-driven to hypothesis-driven

The microbiome is in a symbiotic relationship with the host. Among the microbial consortia in the human body, that in the oral cavity is complex. Instead of repeatedly confirming biomarkers of oral and systemic diseases, recent studies have focused on a unified clinical diagnostic standard in microbiology that reduces the heterogeneity caused by individual discrepancies. Research has also been conducted on other topics of greater clinical importance, including bacterial pathogenesis, and the effects of drugs and treatments. In this review, we divide existing research into technology-driven and hypothesis-driven, according to whether there is a clear research hypothesis. This classification allows the demonstration of shifts in the direction of oral microbiology research. Based on the shifts, we suggested that establishing clear hypotheses may be the solution to major research challenges.

Prevalence and Antifungal Susceptibility Profile of Oral Candida spp. Isolates from a Hospital in Slovakia

Oral fungal infections are a worldwide healthcare problem. Although Candida albicans is still the most common yeast involved in the infections of oral cavity, non-Candida albicans Candida species (NCACs) have been highly related to these infections, particularly in older, immunosuppressed or patients with long exposure to antimicrobial drugs. The goal of this work was to perform a quick epidemiological and mycological study on the oral samples collected from a laboratory of a hospital in Slovakia, for 60 days. The samples’ identification was performed by Germ-tube formation test, CHROMID® Candida, Auxacolor 2, ID 32C automated method, and the antifungal susceptibility testing determined by E-test®. Results confirm that comparing with bacteria, yeasts still occur in the lower number, but there is a high rate of antifungal resistance (81.6%)—to, at least one drug—among the collected samples, particularly to azoles and 5′-FC, which is clinically noteworthy.

Impact of the Gastrointestinal Tract Microbiota on Cardiovascular Health and Pathophysiology

ABSTRACT

The microbiota of the gastrointestinal tract (GIT) is an extremely diverse community of microorganisms, and their collective genomes (microbiome) provide a vast arsenal of biological activities, in particular enzymatic ones, which are far from being fully elucidated. The study of the microbiota (and the microbiome) is receiving great interest from the biomedical community as it carries the potential to improve risk-prediction models, refine primary and secondary prevention efforts, and also design more appropriate and personalized therapies, including pharmacological ones. A growing body of evidence, though sometimes impaired by the limited number of subjects involved in the studies, suggests that GIT dysbiosis, i.e. the altered microbial composition, has an important role in causing and/or worsening cardiovascular disease (CVD). Bacterial translocation as well as the alteration of levels of microbe-derived metabolites can thus be important to monitor and modulate, because they may lead to initiation and progression of CVD, as well as to its establishment as chronic state. We hereby aim to provide readers with details on available resources and experimental approaches that are used in this fascinating field of biomedical research, and on some novelties on the impact of GIT microbiota on CVD.

Fusobacterium nucleatum Accelerates Atherosclerosis via Macrophage-Driven Aberrant Proinflammatory Response and Lipid Metabolism

Periodontitis, an oral chronic inflammatory disease, is reported to show an association with atherosclerotic vascular disease. Fusobacterium nucleatum is an oral commensal bacterium that is abundantly implicated in various forms of periodontal diseases; however, its role in the pathogenesis of atherosclerosis is unclear. This study aimed to elucidate the underlying pathogenic mechanisms of atherosclerosis induced by F. nucleatum to provide new insight on the prevention and treatment of atherosclerosis. We used an animal model, that is, ApoE^–/– mice were infected with F. nucleatum by oral gavage, and in vitro co-culture models to assess the pathogenicity of F. nucleatum. The results indicate that F. nucleatum ATCC 25586 invaded aortic tissues and substantially increased the progression of atherosclerotic lesions. In addition, F. nucleatum changed plaque composition into a less-stable phenotype, characterized with increased subcutaneous macrophage infiltration, M1 polarization, lipid deposition, cell apoptosis, and reduced extracellular matrix and collagen content. The serum levels of pro-atherosclerotic factors, such as interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein-1 (MCP-1), c-reactive protein, and oxidized low-density lipoprotein (ox-LDL) and microRNAs (miR-146a, miR-155, and miR-23b) were considerably increased after F. nucleatum stimulation, whereas HDL-c level was reduced. F. nucleatum induced in vitro macrophage apoptosis in a time- and dose-dependent manner. F. nucleatum facilitated ox-LDL–induced cholesterol phagocytosis and accumulation by regulating the expression of lipid metabolism-related genes (AR-A1, ACAT1, ABCA1, and ABCG1). F. nucleatum further worsened the atherosclerotic plaque microenvironment by considerably increasing the levels of IL-6; IL-1β; TNF-α; MCP-1; and MMP-2, 8, and 9 and by suppressing fibronectin (FN) 1 levels during foam cell formation. This study shows that F. nucleatum ATCC 25586 is implicated in atherosclerosis by causing aberrant activation and lipid metabolism in macrophage.

Colorectal Cancer Screening in Inflammatory Bowel Diseases-Can Characterization of GI Microbiome Signatures Enhance Neoplasia Detection?

Current noninvasive methods for colorectal cancer (CRC) screening are not optimized for persons with inflammatory bowel diseases (IBDs), requiring patients to undergo frequent interval screening via colonoscopy. Although colonoscopy-based screening reduces CRC incidence in IBD patients, rates of interval CRC remain relatively high, highlighting the need for more targeted approaches. In recent years, the discovery of disease-specific microbiome signatures for both IBD and CRC has begun to emerge, suggesting that stool-based biomarker detection using metagenomics and other culture-independent technologies may be useful for personalized, early, noninvasive CRC screening in IBD patients. Here we discuss the utility of the stool microbiome as a noninvasive CRC screening tool. Comparing the performance of multiple microbiome-based CRC classifiers, including several multi-cohort meta-analyses, we find that noninvasive detection of colorectal adenomas and carcinomas from microbial biomarkers is an active area of study with promising early results.

Interleukin-17 is disease promoting in early stages and protective in late stages of experimental periodontitis

Periodontitis is one of the most common infectious diseases in humans. It is characterized by a chronic inflammation of the tooth-supporting tissue that results in bone loss. However, the role and source of the pro-inflammatory cytokine interleukin-17 (IL-17) and of the cells producing it locally in the gingiva is still controversial. Th17 αβ T cells, CD4⁺ exFoxP3⁺ αβ T cells, or IL-17-producing γδ T cells (γδ17 cells) seem to be decisive cellular players in periodontal inflammation. To address these issues in an experimental model for periodontitis, we employed genetic mouse models deficient for either γδ T cells or IL-17 cytokines and assessed the bone loss during experimental periodontal inflammation by stereomicroscopic, histological, and μCT-analysis. Furthermore, we performed flow-cytometric analyses and qPCR-analyses of the gingival tissue. We found no γδ T cell- or IL-17-dependent change in bone loss after four weeks of periodontitis. Apart from that, our data are complementary with earlier studies, which suggested IL-17-dependent aggravation of bone loss in early periodontitis, but a rather bone-protective role for IL-17 in late stages of experimental periodontitis with respect to the osteoclastogenicity defined by the RANKL/OPG ratio.

Oral Microbiome Is Associated With Incident Hypertension Among Postmenopausal Women

Background Oral microbiota are thought to influence blood pressure (BP) regulation. However, epidemiological data supporting this hypothesis are limited. We examined associations between oral microbiota, BP, and incident hypertension in postmenopausal women. Methods and Results Baseline (1997-2001) examinations were completed on 1215 women (mean age, 63 years) during which subgingival plaque was collected, BP was measured, and medical and lifestyle histories and medication inventory were obtained. Microbiome composition of subgingival plaque was measured using 16S ribosomal RNA gene amplicon sequencing. Baseline measured BP was defined as normotensive (systolic <120 mm Hg and diastolic <80 mm Hg, no BP medication use; n=429); elevated (systolic ≥120 mm Hg or diastolic ≥80 mm Hg, no medication use; n=306); or prevalent treated hypertension (history of physician diagnosis treated with medications; n=480). Incident hypertension (375 cases among 735 without baseline treated hypertension) was defined as newly physician-diagnosed hypertension treated with medication reported on annual health surveys (mean follow-up, 10.4 years). Cross-sectional analysis identified 47 bacterial species (of 245 total) that differed significantly according to baseline BP status (P<0.05). Prospective analysis identified 15 baseline bacterial species significantly (P<0.05) associated with incident hypertension: 10 positively (age-adjusted hazard ratios [HRs], 1.10-1.16 per SD in bacterial abundance) and 5 inversely (HRs, 0.82-0.91) associated. Associations were materially unchanged after further adjustment for demographic, clinical, and lifestyle factors; were similar when analysis was restricted to the normotensive group; and were of consistent magnitudes between strata of baseline age, smoking, body mass index, and BP categories. Conclusions Specific oral bacteria are associated with baseline BP status and risk of hypertension development among postmenopausal women. Research to confirm these observations and elucidate mechanisms is needed.

Oral Microbiome: Getting to Know and Befriend Neighbors, a Biological Approach

The oral microbiome, forming a biofilm that covers the oral structures, contains a high number of microorganisms. Biofilm formation starts from the salivary pellicle that allows bacterial adhesion-colonization-proliferation, co-aggregation and biofilm maturation in a complex microbial community. There is a constant bidirectional crosstalk between human host and its oral microbiome. The paper presents the fundamentals regarding the oral microbiome and its relationship to modulator factors, oral and systemic health. The modern studies of oral microorganisms and relationships with the host benefits are based on genomics, transcriptomics, proteomics and metabolomics. Pharmaceuticals such as antimicrobials, prebiotics, probiotics, surface active or abrasive agents and plant-derived ingredients may influence the oral microbiome. Many studies found associations between oral dysbiosis and systemic disorders, including autoimmune diseases, cardiovascular, diabetes, cancers and neurodegenerative disorders. We outline the general and individual factors influencing the host-microbial balance and the possibility to use the analysis of the oral microbiome in prevention, diagnosis and treatment in personalized medicine. Future therapies should take in account the restoration of the normal symbiotic relation with the oral microbiome.

Oral bacteria, oral health, and adverse pregnancy outcomes

The link between oral health and adverse pregnancy outcomes has been suggested by numerous epidemiological studies. More recent studies indicate the relationship between severity of periodontal disease and adverse pregnancy outcomes. Two virulence mechanisms are proposed: direct invasion of oral microorganisms or their components into the fetal-placenta unit and inflammatory mediators produced in the oral cavity affecting the fetal-placenta unit. While interventional periodontal therapy still yielded contradictory results, animal studies suggest that maternal supplementation of omega-3 fatty acids protects the fetus by suppressing inflammation as well as bacteria proliferation in the placenta. This article reviews the recent epidemiological, mechanistic, interventional, and therapeutic studies of oral health and adverse pregnancy outcomes.

Innate Phagocyte Polarization in the Oral Cavity

The oral cavity is a complex environment constantly exposed to antigens from food and the oral microbiota. Innate immune cells play an essential role in maintaining health and homeostasis in the oral environment. However, these cells also play a significant role in disease progression. This review will focus on two innate phagocytes in the oral cavity: macrophages and neutrophils, and examine their roles during homeostasis and disease development, with a focus on periodontal disease and cancer. Macrophages have a well-known ability to polarize and be activated towards a variety of phenotypes. Several studies have found that macrophages’ polarization changes can play an essential role in maintaining health in the oral cavity and contribute to disease. Recent data also finds that neutrophils display phenotypic heterogeneity in the oral cavity. In both cases, we focus on what is known about how these cellular changes alter these immune cells’ interactions with the oral microbiota, including how such changes can lead to worsening, rather than improving, disease states.

Probiotics-Containing Mucoadhesive Gel for Targeting the Dysbiosis Associated with Periodontal Diseases

Objective

Periodontitis is a common disorder that leads to the loss of both tooth and personal well-being, contributing to worsen the risk for metabolic and cardiovascular diseases. Recently, probiotics, characterized by rapid oral dispersion, have been topically used. Here, we present data of a mucoadhesive gel containing probiotics, capable of ensuring a slow release of bacteria to prevent and treat periodontitis.

Methods

An original mucoadhesive gel (AL0005) that is anhydrous and of food grade, loaded with the blend of lactobacilli and plants' dry extracts, has been assayed.

Results

The release kinetics of the bacterial mixture in different experimental models in vitro, including simulated saliva or physiological solutions, showed a significant and stable release for 5–8 hours. In one in vivo study of a mouse model of periodontitis, a locally applied mucoadhesive gel enriched with probiotic strains improved significantly the tissue pathology when compared with vehicle-exposed mice.

Conclusions

Together, the results suggest that this mucoadhesive gel can be useful in the normalization of the gum bacterial flora and improvement of the tissue pathology of gum disorders.

A positive feed-forward loop between Fusobacterium nucleatum and ethanol metabolism reprogramming drives laryngeal cancer progression and metastasis

Alcohol consumption, which affects the structure and composition of the laryngeal microbiota, is one of the most important risk factors for laryngeal squamous cell cancer (LSCC). Our results demonstrated that high enrichment of Fusobacterium nucleatum (F. nucleatum) in LSCC was associated with poor prognosis. F. nucleatum increased miR-155-5p and miR-205-5p expression to suppress alcohol dehydrogenase 1B (ADH1B) and transforming growth factor β receptor 2 (TGFBR2) expression by activating innate immune signaling, resulting in ethanol metabolism reprogramming to allow F. nucleatum accumulation and PI3K/AKT signaling pathway activation to promote epithelial-mesenchymal transition, further exacerbating the uncontrolled progression and metastasis of LSCC. Therefore, the positive feed-forward loop between F. nucleatum and ethanol metabolism reprogramming promotes cell proliferation, migration, and invasion to affect LSCC patient prognosis. The amount of F. nucleatum is a potential prognostic biomarker, which yields valuable insight into clinical management that may improve the oncologic outcome of patients with LSCC.

The Role of Candida albicans Virulence Factors in the Formation of Multispecies Biofilms With Bacterial Periodontal Pathogens

Periodontal disease depends on the presence of different microorganisms in the oral cavity that during the colonization of periodontal tissues form a multispecies biofilm community, thus allowing them to survive under adverse conditions or facilitate further colonization of host tissues. Not only numerous bacterial species participate in the development of biofilm complex structure but also fungi, especially Candida albicans, that often commensally inhabits the oral cavity. C. albicans employs an extensive armory of various virulence factors supporting its coexistence with bacteria resulting in successful host colonization and propagation of infection. In this article, we highlight various aspects of individual fungal virulence factors that may facilitate the collaboration with the associated bacterial representatives of the early colonizers of the oral cavity, the bridging species, and the late colonizers directly involved in the development of periodontitis, including the “red complex” species. In particular, we discuss the involvement of candidal cell surface proteins—typical fungal adhesins as well as originally cytosolic “moonlighting” proteins that perform a new function on the cell surface and are also present within the biofilm structures. Another group of virulence factors considered includes secreted aspartic proteases (Sap) and other secreted hydrolytic enzymes. The specific structure of the candidal cell wall, dynamically changing during morphological transitions of the fungus that favor the biofilm formation, is equally important and discussed. The non-protein biofilm-composing factors also show dynamic variability upon the contact with bacteria, and their biosynthesis processes could be involved in the stability of mixed biofilms. Biofilm-associated changes in the microbe communication system using different quorum sensing molecules of both fungal and bacterial cells are also emphasized in this review. All discussed virulence factors involved in the formation of mixed biofilm pose new challenges and influence the successful design of new diagnostic methods and the application of appropriate therapies in periodontal diseases.

A Correlation Study of the Microbiota Between Oral Cavity and Tonsils in Children With Tonsillar Hypertrophy

Tonsillar hypertrophy is a common disease in 3-to-6-year-old children, which may cause serve symptoms like airway obstruction. Microbiological factors play an important role in the etiology of tonsillar hypertrophy. As the starting point of digestive and respiratory tracts, the microbial composition of the oral cavity is not only unique but also closely related to the resident microbiota in other body sites. Here we reported a correlation study of the microbiota between oral cavity and tonsils in children with tonsillar hypertrophy. Saliva, supragingival plaque, and wiped samples from the tonsil surface were collected from both tonsillar hypertrophy patients and participants with healthy tonsils and were then analyzed using Illumina Miseq Sequencing of the 16S rRNA gene. In the tonsillar hypertrophic state, more genera were detected on the tonsil surface than in the tonsil parenchyma, with more intra-microbiota correlations. When tonsillar hypertrophy occurred, both the oral cavity and tonsil surface endured microbiome shift with increased genera category and more active bacterial interactions. Over half of the newly detected genera from the tonsillar hypertrophic state were associated with infection and inflammation process or exhibited antibiotic-resistant characters. Of each individual, the microbial composition and structure of saliva seemed more similar to that of the tonsil surface, compared with the supragingival plaque. In salivary microbiota, genus Johnsonella might be relative with the healthy state of tonsils, while Pseudoxanthomonas might be relative with tonsillar hypertrophy. Our study supported the link between oral microbiota with the healthy and hypertrophic states of tonsils and may provide new directions for future researches in the specific role of oral microbiota in the etiology of tonsil diseases.

Periodontal disease as a risk factor for sporadic colorectal cancer: results from COLDENT study

Colorectal cancer remains the top leading cancer worldwide. Accumulating evidence suggests periodontal pathogens are involved in colorectal carcinogenesis, indicating the need for high-quality epidemiological evidence linking periodontal disease (PD) and colorectal cancer (CRC). Thus, we conducted the first population-based case–control study that was specifically designed to investigate the association between compromised oral health and sporadic CRC. A total of 348 incident cases of colon or rectal cancer, and 310 age and sex frequency-matched controls, from the Montreal island and Laval population participated in the study. Data were collected on PD and on several CRC risk factors using validated questionnaires. A life-course approach was used to document long-term history regarding lifestyle factors. Multivariable unconditional logistic regression analysis was used to estimate the rate ratio (RR) quantifying the association between CRC and PD. Results showed that the rate of new diagnosis of CRC in persons with a positive history of PD was 1.45 times higher than in those with a negative history of PD adjusting for age, sex, BMI, education, income, diabetes, family history of CRC, regular use of non-steroidal anti-inflammatory drugs, lifetime cumulative smoking, lifetime consumption of red meats, processed meats, and alcoholic drinks, and lifetime total physical activity score (adjusted RR = 1.45; 95% CI 1.04–2.01; p = 0.026). Our results support the hypothesis of an association between PD and sporadic CRC risk.

Microbiological Aspects of Root Canal Infections and Disinfection Strategies: An Update Review on the Current Knowledge and Challenges

The oral cavity is the habitat of several hundreds of microbial taxa that have evolved to coexist in multispecies communities in this unique ecosystem. By contrast, the internal tissue of the tooth, i.e., the dental pulp, is a physiologically sterile connective tissue in which any microbial invasion is a pathological sign. It results in inflammation of the pulp tissue and eventually to pulp death and spread of inflammation/infection to the periradicular tissues. Over the past few decades, substantial emphasis has been placed on understanding the pathobiology of root canal infections, including the microbial composition, biofilm biology and host responses to infections. To develop clinically effective treatment regimens as well as preventive therapies, such extensive understanding is necessary. Rather surprisingly, despite the definitive realization that root canal infections are biofilm mediated, clinical strategies have been focused more on preparing canals to radiographically impeccable levels, while much is left desired on the debridement of these complex root canal systems. Hence, solely focusing on "canal shaping" largely misses the point of endodontic treatment as the current understanding of the microbial aetiopathogenesis of apical periodontitis calls for the emphasis to be placed on "canal cleaning" and chemo-mechanical disinfection. In this review, we dissect in great detail, the current knowledge on the root canal microbiome, both in terms of its composition and functional characteristics. We also describe the challenges in root canal disinfection and the novel strategies that attempt to address this challenge. Finally, we provide some critical pointers for areas of future research, which will serve as an important area for consideration in Frontiers in Oral Health.

Candida albicans and Candida dubliniensis in Periodontitis in Adolescents and Young Adults

Aim

This study aims to evaluate the association of Candida albicans and Candida dubliniensis with periodontitis in adolescents and young adults in a Moroccan population.

Methods

426 subjects aged between 12 and 25 years were recruited for the study. A pool of plaque sample was taken. Samples were cultured on Sabouraud Chloramphenicol medium at 37°C for 24–48 hours and then identified by the Vitek 2 YST system. Clinical data and presence of Candida albicans and Candida dubliniensis were analyzed using Jamovi (Version 1.8).

Results

Candida albicans was observed in 25 subjects among 68 diseased patients (37%) and in 60 subjects among 358 healthy patients (17%). It can be reported that under normal yeast conditions, there is a statistically significant difference between these two groups (P < 0.001). Candida dubliniensis was more prevalent in periodontitis than in healthy subjects (P=0.026). Regarding clinical variables, subgroups of periodontitis subjects showed significant statistical differences for periodontal probing depth, clinical attachment loss, and number of decayed teeth in advanced periodontitis in comparison with initial or mild periodontitis. The results also indicate that the presence of the two species of Candida is not related to gender or age (P > 0.05) nor related to the severity of the periodontal disease in this population.

Conclusion

Within the limits of our study, Candida albicans is more frequently associated with periodontitis. The potential role of C. albicans in periodontitis pathogenesis is very complex. More studies on biofilm associated with different forms of periodontitis are necessary. It is also important to assess the coexistence of periodontitis and caries and the associated biofilms.

The Role of Lipopolysaccharide-Induced Cell Signalling in Chronic Inflammation

Lipopolysaccharide (LPS) is the main structural component of the outer membrane of most Gram-negative bacteria and has diverse immunostimulatory and procoagulant effects. Even though LPS is well described for its role in the pathology of sepsis, considerable evidence demonstrates that LPS-induced signalling and immune dysregulation are also relevant in the pathophysiology of many diseases, characteristically where endotoxaemia is less severe. These diseases are typically chronic and progressive in nature and span broad classifications, including neurodegenerative, metabolic, and cardiovascular diseases. This Review reappraises the mechanisms of LPS-induced signalling and emphasises the crucial contribution of LPS to the pathology of multiple chronic diseases, beyond conventional sepsis. This perspective asserts that new ways of approaching chronic diseases by targeting LPS-driven pathways may be of therapeutic benefit in a wide range of chronic inflammatory conditions.

New Insights into the Role of Oral Microbiota Dysbiosis in the Pathogenesis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of chronic intestinal inflammatory disorders with a prolonged duration characterized by recurrent relapse and remission. The exact etiology of IBD remains poorly understood despite the identification of relevant risk factors, including individual genetic susceptibility, environmental triggers, and disruption of immune homeostasis. Dysbiosis of the gut microbiota is believed to exacerbate the progression of IBD. Recently, increasing evidence has also linked oral microbiota dysbiosis with the development of IBD. On the one hand, IBD patients show significantly unbalanced composition and function of the oral microbiota known as dysbiosis. On the other, overabundances of oral commensal bacteria with opportunistic pathogenicity have been found in the gut microbiota of IBD patients. Herein, we review the current information on the causative factors of IBD, especially recent evidence of IBD-associated oral microbiota dysbiosis, which has seldom been covered in the previous literature review, highlighting the pathogenic mechanisms of specific oral bacteria in the development of IBD. Ectopic colonization of several oral bacteria, including a subset of Porphyromonas gingivalis, Streptococcus mutans, Fusobacterium nucleatum, Campylobacter concisus, and Klebsiella pneumoniae, may lead to destruction of the intestinal epithelial barrier, excessive secretion of inflammatory cytokines, disruption of the host immune system, and dysbiosis of gut microbiota, consequently aggravating chronic intestinal inflammation. Studying oral microbiota dysbiosis may open future horizons for understanding IBD pathogenesis and provide novel biomarkers for IBD. This review also presents the current treatment and new perspectives for IBD treatment.

Another Look at the Contribution of Oral Microbiota to the Pathogenesis of Rheumatoid Arthritis: A Narrative Review

Although autoimmunity contributes to rheumatoid arthritis (RA), several lines of evidence challenge the dogma that it is mainly an autoimmune disorder. As RA-associated human leukocyte antigens shape microbiomes and increase the risk of dysbiosis in mucosae, RA might rather be induced by epigenetic changes in long-lived synovial presenting cells, stressed by excessive translocations into joints of bacteria from the poorly cultivable gut, lung, or oral microbiota (in the same way as more pathogenic bacteria can lead to "reactive arthritis"). This narrative review (i) lists evidence supporting this scenario, including the identification of DNA from oral and gut microbiota in the RA synovium (but in also healthy synovia), and the possibility of translocation through blood, from mucosae to joints, of microbiota, either directly from the oral cavity or from the gut, following an increase of gut permeability worsened by migration within the gut of oral bacteria such as Porphyromonas gingivalis; (ii) suggests other methodologies for future works other than cross-sectional studies of periodontal microbiota in cohorts of patients with RA versus controls, namely, longitudinal studies of oral, gut, blood, and synovial microbiota combined with transcriptomic analyses of immune cells in individual patients at risk of RA, and in overt RA, before, during, and following flares of RA.

Differences in the oral and intestinal microbiotas in pregnant women varying in periodontitis and gestational diabetes mellitus conditions

Background: The present study aimed to investigate the potential association between oral and intestinal microbiotas of pregnant women with periodontitis and/or gestational diabetes mellitus (GDM) in the second trimester.Methods: Four groups were defined: periodontitis (n = 28), GDM (n = 7), periodontitis + GDM (n = 7), and periodontitis- and GDM-free controls (n = 27). The oral and intestinal microbiomes were analyzed using the 16S rRNA sequencing technique.Results: Periodontitis alone significantly decreased the oral microbial diversity (by Shannon index, p = 0.003) and changed the structure of the oral microbial community (by AMOVA, p 0.001). GDM alone significantly increased the oral microbial diversity (by Shannon index, p = 0.049), and when combined with periodontitis, GDM significantly decreased the intestinal microbial richness (by observed species, p = 0.018) and influenced the structure of intestinal microbial community (by AMOVA, p = 0.043). The differentially abundant microbial taxa among different groups in both oral and intestinal samples were identified by LEfSe analysis, and limited taxa showed consistent trends. The numbers and ratios of oral-intestinal shared operational taxonomical units were the least in the periodontitis + GDM group.Conclusions: A close relationship between the oral microbiota and pregnant periodontitis was shown. Significant changes occur in both the oral and intestinal microbiomes when periodontitis was coupled with GDM. A separate influence of periodontitis and GDM on the oral and intestinal microbiotas may be indicated.

Detection of Fusobacterium nucleatum subspecies in the saliva of pre-colorectal cancer patients, using tandem mass spectrometry

OBJECTIVE

Rising evidence links Fusobacterium nucleatum (F. nucleatum) with its four subspecies; nucleatum, polymorphum, animalis, and vincentii, with the development of colorectal cancer (CRC) and its precursor colorectal adenoma (CRA). This study aims to optimize a technique for and explore the capability of matrix-assisted laser-desorption ionization-tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) to detect F. nucleatum subspecies directly from the saliva samples of CRA patients and controls without preculturing.

DESIGN

Saliva samples were collected from four CRA patients and eight controls. Proteins were extracted and subjected to solid-phase extraction fractionation, enzymatically digested, and analyzed by MALDI-TOF/TOF MS. F. nucleatum subspecies strains were cultured and used as a positive control.

RESULTS

A proteomics approach was developed to identify F. nucleatum subspecies directly from saliva samples. With this approach, the bacterial culturing step, which could take up to seven days, was bypassed. Overall, 157 F. nucleatum subspecies proteins were detected in the saliva samples. F. nucleatum subsp. nucleatum was absent in the patients while detected in half of the controls.

CONCLUSION

This study presents a novel technique for detecting F. nucleatum subspecies from saliva specimens that could later be employed to better understand a potential role of those subspecies in CRC development.

Dysbiosis in salivary bacterial diversity of postpartum females and its association with oral health problems and APOs

The present study investigates the dysbiosis in salivary bacterial diversity by culture-dependent and independent methods. Culturable aerobic and facultative anaerobic bacterial diversity was studied in saliva collected from 267 postpartum and 54 nonpregnant females by using standard microbiological methods. For unculturable bacterial diversity, DNA from saliva samples of four selected females was sequenced by targeting V4 region of 16S rRNA. In postpartum females, S. mutans was significantly more prevalent. Its colonization was also seen significant among females having gingivitis (P < 0.01), dental caries (P < 0.01), and in those giving birth to low weight baby. In postpartum group, 65.16% females were culture positive for Staphylococcus, 12.73% Gram positive rods, 10.48% N. meningitides, 6.36% K. pneumoniae, 5.61% Enterobacter species and 2.62% E. coli. Isolates showed high biofilm forming ability and antibiotic resistance. Upon analysis of unculturable bacterial diversity, a total of 16 phyla and 156 genera were observed. Alpha diversity was decrease in postpartum female having oral health issues with pre-term low weight birth, compared to females with full term birth. Bray-Curtis dissimilarity was highest between female with dental issues and different pregnancy outcomes. Bacterial diversity and abundance altered among females with different oral health conditions and pregnancy outcomes, and also have pathogenic potential.

Chronic cannabis smoking-enriched oral pathobiont drives behavioral changes, macrophage infiltration, and increases β-amyloid protein production in the brain

BACKGROUND

Little is known about chronic cannabis smoking-associated oral microbiome and its effects on central nervous system (CNS) functions.

METHODS

In the current study, we have analyzed the saliva microbiome in individuals who chronically smoked cannabis with cannabis use disorder (n = 16) and in non-smoking controls (n = 27). The saliva microbiome was analyzed using microbial 16S rRNA sequencing. To investigate the function of cannabis use-associated oral microbiome, mice were orally inoculated with live Actinomyces meyeri, Actinomyces odontolyticus, or Neisseria elongata twice per week for six months, which mimicked human conditions.

FINDINGS

We found that cannabis smoking in humans was associated with oral microbial dysbiosis. The most increased oral bacteria were Streptococcus and Actinomyces genus and the most decreased bacteria were Neisseria genus in chronic cannabis smokers compared to those in non-smokers. Among the distinct species bacteria in cannabis smokers, the enrichment of Actinomyces meyeri was inversely associated with the age of first cannabis smoking. Strikingly, oral exposure of Actinomyces meyeri, an oral pathobiont, but not the other two control bacteria, decreased global activity, increased macrophage infiltration, and increased β-amyloid 42 protein production in the mouse brains.

INTERPRETATION

This is the first study to reveal that long-term oral cannabis exposure is associated oral enrichment of Actinomyces meyeri and its contributions to CNS abnormalities.