Role Of Oral Microbiota Research Articles

Oral and Gut Microbial Diversity and Immune Regulation in Patients with HIV on Antiretroviral Therapy.

Despite evidence of a chronic inflammatory phenotype in people living with HIV (PLWH) on antiretroviral therapy (ART), the role of oral microbiota in chronic immune activation has not been fully explored. We aimed to determine the relationship between oral and gut microbiome diversity and chronic systemic inflammation in ART-treated PLWH with prevalent severe periodontitis, an inflammatory condition commonly associated with HIV infection. We assessed bacterial and fungal communities at oral and gastrointestinal sites in a cohort (n = 52) of primarily postmenopausal women on ART using 16S rRNA and internal transcribed spacer (ITS) sequencing and measured cellular and soluble markers of inflammation and immune dysfunction. Linear mixed-effect regression and differential abundance analyses were used to associate clinical characteristics and immunological markers with bacterial and fungal diversity and community composition. Bacterial α-diversity in plaque, saliva, and gut was associated with different immunological markers, while mycobial diversity was not associated with soluble or cellular biomarkers of immune stimulation or T cell dysfunction. Furthermore, lipopolysaccharide-positive (LPS+) bacteria previously linked to inflammatory outcomes were enriched at oral sites in patients with severe periodontitis. Fungal α-diversity was reduced in plaque from teeth with higher clinical attachment loss, a marker of periodontitis, and in saliva and plaque from patients with a history of AIDS. Our results show that both bacterial and fungal oral microbiome communities likely play a role in chronic systemic immune activation in PLWH. Thus, interventions targeting both inflammation and the microbiome, particularly in the oral cavity, may be necessary to reduce chronic immune dysregulation in patients with HIV.IMPORTANCE A feedback loop between dysbiotic gut microbiota, increased translocation of microbial products such as lipopolysaccharide, and inflammation has been hypothesized to cause immune system dysfunction in early HIV infection. However, despite evidence of a chronic inflammatory phenotype in patients on antiretroviral therapy (ART), the role of oral microbiota in systemic immune activation and the relationship between oral and gut bacterial and fungal diversity have not been explored. Our study suggests a crucial role for oral bacterial and fungal communities in long-term systemic immune activation in patients on ART, expanding the current paradigm focused on gut bacteria. Our results indicate that interventions targeting both inflammation and microbial diversity are needed to mitigate oral inflammation-related comorbidities, particularly in HIV-positive patients. More broadly, these findings can bolster general models of microbiome-mediated chronic systemic immune activation and aid the development of precise microbiota-targeted interventions to reverse chronic inflammation.

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 Microbiome: A New Biomarker Reservoir for Oral and Oropharyngeal Cancers.

Current biomarkers (DNA, RNA and protein) for oral cavity and oropharyngeal cancers demonstrate biological variations between individuals, rendering them impractical for clinical translation. Whilst these biomarkers originate from the host, there is not much information in the literature about the influence of oral microbiota on cancer pathogenesis, especially in oral cancers. Oral microbiotas are known to participate in disease initiation and progression not only limited to the oral cavity, but also at other distant sites. Due to the close proximity of oral microbiota and oral cavity and oropharyngeal tumours, abundance changes in oral microbiota may provide useful information on tumourigenesis. This review aims to highlight information on the role of oral microbiota in oral cavity and oropharyngeal cancers. An in-depth analysis into the oral microbiota may provide a new avenue to diagnose and treat these patients.

Metabolic and Community Synergy of Oral Bacteria in Colorectal Cancer

ABSTRACTThe oral periodontopathic bacterium Fusobacterium nucleatum has been repeatedly associated with colorectal tumors. Molecular analysis has identified specific virulence factors that promote tumorigenesis in the colon. However, other oral community members, such as members of the Porphyromonas spp., are also found with F. nucleatum on colonic tumors, and thus, narrow studies of individual pathogens do not take community-wide virulence properties into account. A broader view of oral bacterial physiology and pathogenesis identifies two factors that could promote colonization and persistence of oral bacterial communities in the colon. The polymicrobial nature of oral biofilms and the asaccharolytic metabolism of many of these species make them well suited to life in the microenvironment of colonic lesions. Consideration of these two factors offers a novel perspective on the role of oral microbiota in the initiation, development, and treatment of colorectal cancer.

Oral microbiota: a promising predictor of human oral and systemic diseases

A human oral microbiota is the ecological community of commensal, symbiotic, and pathogenic microorganisms found in human oral cavity. Oral microbiota exists mostly in the form of a biofilm and maintains a dynamic ecological equilibrium with the host body. However, the disturbance of this ecological balance inevitably causes oral infectious diseases, such as dental caries, apical periodontitis, periodontal diseases, pericoronitis, and craniofacial bone osteomyelitis. Oral microbiota is also correlated with many systemic diseases, including cancer, diabetes mellitus, rheumatoid arthritis, cardiovascular diseases, and preterm birth. Hence, oral microbiota has been considered as a potential biomarker of human diseases. The "Human Microbiome Project" and other metagenomic projects worldwide have advanced our knowledge of the human oral microbiota. The integration of these metadata has been the frontier of oral microbiology to improve clinical translation. By reviewing recent progress on studies involving oral microbiota-related oral and systemic diseases, we aimed to propose the essential role of oral microbiota in the prediction of the onset, progression, and prognosis of oral and systemic diseases. An oral microbiota-based prediction model helps develop a new paradigm of personalized medicine and benefits the human health in the post-metagenomics era.

Metagenomics: A New Realm of Uncultured Periodontal Microbes

With over 400 bacterial species the periodontal microbiota has clearly a diverse ecology and uncultivated organisms are found to be associated with the periodontal diseases. Many efforts have been made to determine why so many bacterial species cannot be cultured on conventional bacteriological media and to develop new cultural methods for their isolation. In recent years, metagenomic analysis is available, based on the direct examination of nucleic acids from samples.This review will address the new dimensions of this novel procedure which will lead to a better understanding of the role of oral microbiota in periodontal disease. DOI: http://dx.doi.org/10.3329/bjdre.v3i2.16611 Bangladesh Journal of Dental Research & Education Vol.3(2) 2013: 36-40

Human Atherosclerotic Plaque Contains Viable Invasive Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

To the Editor: Because epidemiological evidence supports an association between cardiovascular and periodontal disease, we assessed whether periodontal pathogens were present in atherosclerotic lesions. To detect invasive bacteria, the natural tropism of the bacteria toward human tissues was exploited. Further, bacterial presence was demonstrated using quantitative polymerase chain reaction (Q-PCR). This confirms the presence of periodontal pathogens in atherosclerotic lesions, whereby the bacteria could contribute to the vascular pathology either directly through their cytotoxicity or indirectly by inducing or exacerbating inflammation. Cardiovascular disease (CVD) is the leading cause of death in the in the United States.1 According to the American Heart Association’s statistics from 2003, there were no previous symptoms in 50% of men and 63% of women who died suddenly from CHD. In a 10-year follow-up study, ≈25% of coronary deaths in males and 15% in females occurred in persons in the lowest two quintiles of the multivariate Framingham Heart Study risk scores.2 This and other data have led to an emerging paradigm shift from coronary heart disease having a purely hereditary/nutritional causation to possibly having an infectious component.3 Many epidemiological studies strongly suggest that periodontitis may be a risk factor for coronary heart disease (CHD).4 Serologically, edentulousness and serum IgG-antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in 1163 men were recently shown to be associated with CHD.5 In a larger prospective study of 6950 subjects, the same authors provide serological evidence that an infection caused by major periodontal pathogens is associated with future stroke.6 Previous studies have identified 16S rRNA of oral microbial pathogens, including P gingivalis and A actinomycetemcomitans , …