Oral Microbiota Is Associated With Immune Recovery in Human Immunodeficiency Virus-Infected Individuals

The role of the oral microbiota in HIV-infected individuals deserves attention as either HIV infection or antiretroviral therapy (ART) may have effect on the diversity and the composition of the oral microbiome. However, few studies have addressed the oral microbiota and its interplay with different immune responses to ART in HIV-infected individuals. Salivary microbiota and immune activation were studied in 30 HIV-infected immunological responders (IR) and 34 immunological non-responders (INR) (≥500 and < 200 CD4 + T-cell counts/μl after 2 years of HIV-1 viral suppression, respectively) with no comorbidities. Metagenome sequencing revealed that the IR and the INR group presented similar salivary bacterial richness and diversity. The INR group presented a significantly higher abundance of genus Selenomonas_4, while the IR group manifested higher abundances of Candidatus_Saccharimonas and norank_p_Saccharimonas. Candidatus_Saccharimonas and norank_p_Saccharimonas were positively correlated with the current CD4 + T-cells. Candidatus_Saccharimonas was positively correlated with the markers of adaptive immunity CD4 + CD57 + T-cells, while negative correlation was found between norank _p_Saccharimonas and the CD8 + CD38 + T-cells as well as the CD4/CD8 + HLADR + CD38 + T-cells. The conclusions are that the overall salivary microbiota structure was similar in the immunological responders and immunological non-responders, while there were some taxonomic differences in the salivary bacterial composition. Selenomona_4, Candidatus_Saccharimonas, and norank _p_Saccharimonas might act as important factors of the immune recovery in the immunodeficiency patients, and Candidatus_Saccharimonas could be considered in the future as screening biomarkers for the immune responses in the HIV-infected individuals.

The Mediterranean Diet Positively Affects Resting Metabolic Rate and Salivary Microbiota in Human Subjects: A Comparison with the Vegan Regimen

Salivary microbiota, comprising bacteria shed from oral surfaces, has been shown to be individualized, temporally stable, and influenced by macronutrient intake and lifestyle. Nevertheless, the effect of long-term dietary patterns on oral microbiota composition and the relationship between oral microbiota composition and metabolic rate remains to be examined. Herein, salivary microbiota composition and metabolic profile were analyzed in human subjects with vegan (VEG) or Mediterranean (MED) long-term dietary patterns. MED subjects presented significantly higher percentages of Subflava and Prevotella species as compared to VEG ones. Moreover, MED subjects showed a lower carbohydrate and a higher lipid consumption than VEG subjects, and, accordingly, a significantly higher basal metabolic rate (BMR) and a lower respiratory quotient (RQ). Prevotella abundance was demonstrated to be inversely related to RQ and carbohydrate consumption, whereas Subflava percentages were demonstrated to be positively correlated to BMR. Lactobacillus abundance, which was inversely related to Subflava presence in MED subjects, was associated with decreased BMR (Harris–Benedict) values. Overall, our data evidence the influence of macronutrient intake on metabolic profile and oral microbiota and confirm the positive effects of the Mediterranean diet on BMR and on the abundance of microbial species associated with a better macronutrient metabolism.

Salivary Microbiota Is Significantly Less Diverse in Patients with Chronic Spontaneous Urticaria Compared to Healthy Controls: Preliminary Results

Background: Because of the important role in regulating the immune system, increasing evidence suggests a possible implication of gut microbiota in Chronic spontaneous urticaria (CSU). Although the oral cavity is the first site of contact between microbiota and the immune system, the association between salivary microbiota and CSU has not yet been reported. Objective: This case-control study aimed to compare differences in salivary microbiota between CSU patients and healthy controls (HC). Twenty-three participants—13 patients with CSU and 10 HC were enrolled; salivary microbiota was determined by molecular approach targeting 16S ribosomal RNA. Terminal restriction fragment length polymorphism (T-RFLP) analysis was performed. Results: Alpha diversity of salivary microbiota in CSU patients was significantly reduced compared to HC, resulting in alteration of the community composition. Species richness determined via the Shannon index was significantly reduced in the CSU group. Conclusion: Dysbiosis of salivary microbiota may contribute to a dysregulated immune system in the development of CSU. To our knowledge, this was the first study that reported an alteration in salivary microbiota composition in CSU patients.

Periodontitis Salivary Microbiota Worsens Colitis

Evidence suggests that periodontitis contributes to the pathogenesis of inflammatory bowel disease, including Crohn’s disease and ulcerative colitis. However, few studies have examined the role of swallowing and saliva in the pathogenesis of gastrointestinal diseases. Saliva contains an enormous number of oral bacteria and is swallowed directly into the intestine. Here, we explored the influence of periodontitis salivary microbiota on colonic inflammation and possible mechanisms in dextran sulfate sodium (DSS)–induced colitis. The salivary microbiota was collected from healthy individuals and those with periodontitis and gavaged to C57BL/6 mice. Periodontitis colitis was induced by DSS for 5 d and ligature for 1 wk. The degree of colon inflammation was evaluated through hematoxylin and eosin staining, ELISA, and quantitative real-time polymerase chain reaction. Immune parameters were measured with quantitative real-time polymerase chain reaction, flow cytometry, and immunofluorescence. The gut microbiota and metabolome analyses were performed via 16S rRNA gene sequencing and liquid chromatography–mass spectrometry. Although no significant colitis-associated phenotypic changes were found under physiologic conditions, periodontitis salivary microbiota exacerbated colitis in a periodontitis colitis model after DSS induction. The immune response more closely resembled the pathology of ulcerative colitis, including aggravated macrophage M2 polarization and Th2 cell induction (T helper 2). Inflammatory bowel disease–associated microbiota, such as Blautia, Helicobacter, and Ruminococcus, were changed in DSS-induced colitis after periodontitis salivary microbiota gavage. Periodontitis salivary microbiota decreased unsaturated fatty acid levels and increased arachidonic acid metabolism in DSS-induced colitis, which was positively correlated with Aerococcus and Ruminococcus, suggesting the key role of these metabolic events and microbes in the exacerbating effect of periodontitis salivary microbiota on experimental colitis. Our study demonstrated that periodontitis contributes to the pathogenesis of colitis through the swallowing of salivary microbiota, confirming the role of periodontitis in systemic disease and providing new insights into the etiology of gastrointestinal inflammatory diseases.

Saliva As A Non-Invasive Specimen For COPD Assessment

Background: People with COPD have been reported to bear a distinct airway microbiota from healthy individuals based on bronchoalveolar lavage (BAL) and sputum samples. Unfortunately, the collection of these samples involves invasive procedures preventing its regular use. Non-invasive samples from the upper airways could constitute an interesting alternative, but its relationship with COPD is still underexplored.We examined the merits of saliva to identify the typical profile of COPD microbiota and test its association with the disease.Methods: Outpatients with COPD and age-sex matched healthy controls were recruited and characterised based on clinical parameters and 16S rRNA profiling of salivary microbiota. A clustering analysis based on patients’ microbiota beta-diversity and logistic regressions were performed to evaluate the association between the microbiota composition and COPD. Results: 128 individuals participated (70 patients and 58 controls). Differential abundance analyses showed differences in patients comparable to the ones previously observed in samples from the lower respiratory tract, i.e., an increase in Proteobacteria (particularly Haemophilus) and loss of microbiota diversity. An unsupervised clustering analysis separated patients in two groups based on microbiota composition differing significantly in the frequency of patients hospitalized due to severe acute exacerbation of COPD (AECOPD) and in the frequency of GOLD D patients. Furthermore, a low frequency of Prevotella was associated with a significantly higher risk of recent severe AECOPD and of being GOLD D.Conclusion: Salivary microbiota showed an association with COPD, particularly with severe exacerbations, supporting the use of this non-invasive specimen for future studies of heterogeneous respiratory diseases like COPD.

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. Among more than 200 toddlers in the New Hampshire Birth Cohort Study, we characterized the association between multiple anthropometric measures of body mass/growth longitudinally and used shotgun metagenomics 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. Certain taxa were consistently associated with growth and modified by sex. Functional examination also showed concordance between microbial metabolic pathways and child growth metrics. 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.

A Parallel Tracking of Salivary and Gut Microbiota Profiles Can Reveal Maturation and Interplay of Early Life Microbial Communities in Healthy Infants

The onset and progression of the salivary and gut microbiota, the transmission and the impact of the salivary microbiota on the development of early fecal microbial communities was herein explored. We characterized the microbiota of 82 faecal and 80 salivary samples, collected from 82 healty newborns at birth, 7, 15, 30, 90 and 180 days of life, by 16S rRNA targeted-metagenomics approach. Correlation heat-maps and co-occurrence networks were used to investigate microbial taxa relationship in saliva, gut and between the two ecosystems. In saliva microbiota, Streptococcus and Staphylococcus appeared as early commensals, dominating this ecosystem through the time, while Fusobacterium, Prevotella, Porphyromonas, Granulicatella and Veillonella were late colonizers. anaerobes as Enterobacteriace, Staphylococcus and Streptococcus, were gut microbiota pioneers, followed by the anaerobic Bifidobacterium, Veillonella, Eggerthella and Bacteroides. Streptococcus, Staphylococcus and Veillonella were shared by gut and saliva ecosystems (core microbiota). Early saliva and gut microbiota seem to evolve independently driven by local adaptation strategies, with the only exception for the oral Streptococcus and Veillonella genera, involved in gut microbiota development as seeding species. A more comprehensive knowledge of how oral microbiota may impact pathophysiological conditions of gut microbiota may open new avenues on the design of postbiotics.