Oral Microbiota Dysbiosis Research Articles

Oral microbiota-induced periodontitis: a new risk factor of metabolic diseases.

It has recently become evident that the periodontium (gingiva, desmodontal ligament, cementum and alveolar bone) and the associated microbiota play a pivotal role in regulating human health and diseases. The oral cavity is the second largest microbiota in the body with around 500 different bacterial species identified today. When disruption of oral cavity and dysbiosis occur, the proportion of strict anaerobic Gram-negative bacteria is then increased. Patients with periodontitis present 27 to 53% more risk to develop diabetes than the control population suggesting that periodontitis is an aggravating factor in the incidence of diabetes. Moreover, dysbiosis of oral microbiota is involved in both periodontal and metabolic disorders (cardiovascular diseases, dyslipidaemia …). The oral diabetic dysbiosis is characterized by a specific bacteria Porphyromonas, which is highly expressed in periodontal diseases and could exacerbate insulin resistance. In this review, we will address the nature of the oral microbiota and how it affects systemic pathologies with a bidirectional interaction. We also propose that using prebiotics like Akkermansia muciniphila may influence oral microbiota as novel therapeutic strategies. The discovery of the implication of oral microbiota for the control of metabolic diseases could be a new way for personalized medicine.

Modulation of Saliva Microbiota through Prebiotic Intervention in HIV-Infected Individuals.

Human immunodeficiency virus (HIV) infection is characterized by an early depletion of the mucosal associated T helper (CD4+) cells that impair the host immunity and impact the oral and gut microbiomes. Although, the HIV-associated gut microbiota was studied in depth, few works addressed the dysbiosis of oral microbiota in HIV infection and, to our knowledge, no studies on intervention with prebiotics were performed. We studied the effect of a six-week-long prebiotic administration on the salivary microbiota in HIV patients and healthy subjects. Also, the co-occurrence of saliva microorganisms in the fecal bacteria community was explored. We assessed salivary and feces microbiota composition using deep 16S ribosomal RNA (rRNA) gene sequencing with Illumina methodology. At baseline, the different groups shared the same most abundant genera, but the HIV status had an impact on the saliva microbiota composition and diversity parameters. After the intervention with prebiotics, we found a drastic decrease in alpha diversity parameters, as well as a change of beta diversity, without a clear directionality toward a healthy microbiota. Interestingly, we found a differential response to the prebiotics, depending on the initial microbiota. On the basis of 100% identity clustering, we detected saliva sequences in the feces datasets, suggesting a drag of microorganisms from the upper to the lower gastrointestinal tract.

Oral microbiota dysbiosis and its association with Henoch-Schönlein Purpura in children

BackgroundThe pathogenesis of microbes in allergic diseases has been demonstrated and our previous research indicates that microbiota causing gut disorders in children is associated with Henoch-Schönlein Purpura. However, the role of oral microbiota in Henoch-Schönlein Purpura remains unknown. MethodA total of 164 children were enrolled, of which 98 were patients with HSP and 66 were healthy children. Oral swab samples were collected for DNA extraction and 16S rRNA gene sequencing, then analyzed for oral microbiota composition. ResultsOral microbiota differed between healthy children and those with HSP. Children with HSP exhibited higher oral microbial diversity and richness than the controls. Firmicutes, Proteobacteria, and Bacteroidetes are the dominant phyla in children with HSP. We used linear discriminant analysis (LDA) effect size (LEfSe) algorithm and detected 21 bacterial taxonomic clades showing statistical differences (12 increased and 9 decreased) in children with HSP. The correlation analyses between clinical data and abundance in microbial community indicated that an abundance of Butyrivibrio sp. negatively correlated with the length of hospital stay (LOS). Haemophilus sp. negatively correlated to IgE and IgM but positively correlated to LOS, with decreasing significantly in patients with HSP. Prevotella positively correlated with IgM. Prevotella nanceiensis positively correlated with IgA, and were abundant in children with HSP. ConclusionsThese results indicate that children with HSP have significantly different oral microbiota compared to healthy children. Although this study does not imply causality, it is helpful to identify the types and pathways of bacteria that can be used to prevent or treat HSP.

Oral health and microbiota status in professional rugby players: A case-control study

ObjectiveElite athletes are prone to develop oral diseases, which could increase the risk for injuries. The aim of this study was to evaluate the oral health and the composition of oral microbiota of elite rugby players compared to the general population. MethodsWe set up a case-control study by screening 24 professional rugby players (PRG) and 22 control patients (CG) for dental and gingival examinations and performed a taxonomic analysis and a predicted functional analysis of oral microbiota. ResultsThe Decay, Missing and Filled (DMF) teeth index (5.54 ± 6.18 versus 2.14 ± 3.01; p = 0.01) and the frequency of gingivitis (58,33% versus 13.63%) were significantly increased in PRG compared to CG. PRG were characterized by a dysbiotic oral microbiota (Shannon Index: 3.32 ± 0.62 in PRG versus 3.79 ± 0.68 in CG; p = 0.03) with an increase of Streptococcus (58.43 ± 16.84 versus 42.60 ± 17.45; p = 0.005), the main genus implicated in caries. Predicted metagenomics of oral microbiota in rugby players was suggestive of a cariogenic metagenome favourable to the development of caries. ConclusionsOur study shows that the oral health of PRG was poorer than the general population. PRG are characterized by a dysbiotic oral microbiota with an increase of the relative abundance of Streptococcus genus, positively correlated to the weight and negatively correlated to the diversity of oral microbiota. Clinical significanceDental screening should be included in the medical follow-up of professional rugby players as a part of their health management. New strategies such as using probiotics like Lactobacillus could help to control the dysbiosis of oral microbiota.

Dysbiosis of oral microbiota and its association with salivary immunological biomarkers in autoimmune liver disease.

The gut microbiota has recently been recognized to play a role in the pathogenesis of autoimmune liver disease (AILD), mainly primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). This study aimed to analyze and compare the composition of the oral microbiota of 56 patients with AILD and 15 healthy controls (HCs) and to evaluate its association with salivary immunological biomarkers and gut microbiota. The subjects included 39 patients with PBC and 17 patients with AIH diagnosed at our hospital. The control population comprised 15 matched HCs. Salivary and fecal samples were collected for analysis of the microbiome by terminal restriction fragment length polymorphism of 16S rDNA. Correlations between immunological biomarkers measured by Bio-Plex assay (Bio-Rad) and the oral microbiomes of patients with PBC and AIH were assessed. Patients with AIH showed a significant increase in Veillonella with a concurrent decrease in Streptococcus in the oral microbiota compared with the HCs. Patients with PBC showed significant increases in Eubacterium and Veillonella and a significant decrease in Fusobacterium in the oral microbiota compared with the HCs. Immunological biomarker analysis showed elevated levels of inflammatory cytokines (IL-1β, IFN-γ, TNF-α, IL-8) and immunoglobulin A in the saliva of patients with AILD. The relative abundance of Veillonella was positively correlated with the levels of IL-1β, IL-8 and immunoglobulin A in saliva and the relative abundance of Lactobacillales in feces. Dysbiosis of the oral microbiota is associated with inflammatory responses and reflects changes in the gut microbiota of patients with AILD. Dysbiosis may play an important role in the pathogenesis of AILD.

Distinct shifts in the oral microbiota are associated with the progression and aggravation of mucositis during radiotherapy

Background and purposeOral mucositis remains one of the most common complications of radiation therapy for patients with head and neck cancer. This study aimed to investigate the dynamic shifts in the oral mucosal microbiota and their association with the progression and aggravation of mucositis in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy. Materials and methodsIn this study, oropharyngeal mucosa of patients were examined regularly, and sampled longitudinally in eight stages of their radiation treatment program: before radiation, and then after 10, 20, 30, 40, 50, 60, and 70 Gy. Based on 16S rRNA gene sequencing and bioinformatics analysis, the characteristics of dynamic variations in oral microbiota during their treatment were investigated. ResultsThe results showed that the mucosal bacterial alpha diversity (richness and evenness) did not change significantly during the entire course of these patient treatments. Notwithstanding 20 genera were found to be significantly positively associated with their radiation dose, whereas 10 genera were negatively associated with it. Notably, two bacterial co-abundance groups (CAG 1 and 2) were identified and the majority of bacteria clustered within the CAG 2 were indeed periodontal disease-associated genera. Most strikingly, many of them, especially Prevotella, Fusobacterium, Treponema and Porphyromonas, showed obvious dynamic synchronous variations in their abundances throughout the course of radiation therapy, where their peaks frequently coincided with the onset of severe mucositis. ConclusionOur results suggest that dysbiosis of oral mucosal microbiota may contribute to exacerbating the severity of mucositis in patients undergoing radiotherapy for nasopharyngeal carcinoma.

Microbiota, cirrhosis, and the emerging oral-gut-liver axis.

Cirrhosis is a prevalent cause of morbidity and mortality, especially for those at an advanced decompensated stage. Cirrhosis development and progression involves several important interorgan communications, and recently, the gut microbiome has been implicated in pathophysiology of the disease. Dysbiosis, defined as a pathological change in the microbiome, has a variable effect on the compensated versus decompensated stage of cirrhosis. Adverse microbial changes, both in composition and function, can act at several levels within the gut (stool and mucosal) and have also been described in the blood and oral cavity. While dysbiosis in the oral cavity could be a source of systemic inflammation, current cirrhosis treatment modalities are targeted toward the gut-liver axis and do not address the oral microbiome. As interventions designed to modulate oral dysbiosis may delay progression of cirrhosis, a better understanding of this process is of the utmost importance. The concept of oral microbiota dysbiosis in cirrhosis is relatively new; therefore, this review will highlight the emerging role of the oral-gut-liver axis and introduce perspectives for future research.

Dysbiosis of oral buccal mucosa microbiota in patients with oral lichen planus.

The bacterial community structure of buccal mucosa in patients with oral lichen planus was evaluated and compared with healthy control. Buccal scraping samples have been taken on 43 oral lichen planus patients (21 erosive and 22 non-erosive) and 21 mucosal healthy volunteers. The V3 hypervariable 16S rDNA region was amplified and sequenced by high-throughput 454 pyrosequencing. 94.26% of the total buccal bacteria were classified into 15 abundant genera. Eight of these abundant genera could be detected in all cases, namely Streptococcus, Prevotella, Haemophilu, Neisseria, Fusobacterium, Leptotrichia, Veillonella and Actinomyces. Four abundant bacteria showed significantly different prevalence at the genus level: Streptococcus was more abundant (P<0.01) in healthy control group, while Fusobacterium (P<0.01), Leptotrichia (P<0.001) and Lautropia (P<0.001) showed higher abundance in OLP group. Few differences can be found between erosive and non-erosive OLP. In general, 19 'core' OTUs at three levels were defined to be OLP specific, comparing with healthy control group. These results suggest that OLP is associated with dysbiosis of the oral microbiome. Further studies should be taken to elucidate the inner relationship between these observed changes and OLP development.

Antimicrobial and Attractant Roles for Chemerin in the Oral Cavity during Inflammatory Gum Disease.

Periodontal inflammation is one of the most common chronic inflammatory conditions in humans. Despite recent advances in identifying and characterizing oral microbiota dysbiosis in the pathogenesis of gum disease, just how host factors maintain a healthy homeostatic oral microbial community or prevent the development of a pathogenic oral microbiota remains poorly understood. An important determinant of microbiota fate is local antimicrobial proteins. Here, we report that chemoattractant protein chemerin, which we recently identified as a potent endogenous antimicrobial agent in body barriers such as the skin, is present in the oral cavity under homeostatic and inflammatory conditions. Chemerin and a chemerin-derived antimicrobial peptide are bactericidal against select bacteria strategically positioned in dental biofilm. Gingival crevicular samples from patients with gingivitis but not periodontitis contain abundant bioactive chemerin capable of inducing CMKLR1-dependent leukocyte migration. Gingipains secreted by the periodontopathogen P. gingivalis inactivate chemerin. Together, these data suggest that as an antimicrobial agent and leukocyte chemoattractant, chemerin likely contributes to antimicrobial immune defense in the oral cavity.

Decreased Diversity of the Oral Microbiota of Patients with Hepatitis B Virus-Induced Chronic Liver Disease: A Pilot Project.

Increasing evidence suggests that altered gut microbiota is implicated in the pathogenesis of hepatitis B virus-induced chronic liver disease (HBV-CLD). However, the structure and composition of the oral microbiota of patients with HBV-CLD remains unclear. High-throughput pyrosequencing showed that decreased oral bacterial diversity was found in patients with HBV-CLD. The Firmicutes/Bacteroidetes ratio was increased significantly, which indicated that dysbiosis of the oral microbiota participated in the process of HBV-CLD development. However, the changing patterns of the oral microbiota in patients with HBV-induced liver cirrhosis (LC) were almost similar to patients with chronic hepatitis B (CHB). HBV infection resulted in an increase in potential H2S- and CH3SH-producing phylotypes such as Fusobacterium, Filifactor, Eubacterium, Parvimonas and Treponema, which might contribute to the increased oral malodor. These key oral-derived phylotypes might invade into the gut as opportunistic pathogens and contribute to altering the composition of the gut microbiota. This study provided important clues that dysbiosis of the oral microbiota might be involved in the development of HBV-CLD. Greater understanding of the relationships between the dysbiosis of oral microbiota and the development of HBV-CLD might facilitate the development of non-invasive differential diagnostic procedures and targeted treatments of HBV-CLD patients harbouring specific oral phylotypes.