Detection of oral bacteria on the tongue dorsum using PCR amplification of 16S ribosomal RNA and its association with systemic disease in middle-aged and elderly patients

Prevalence of oral Capnocytophaga species and their association with dental plaque accumulation and periodontal inflammation in middle‑aged and older people

Capnocytophaga species are commonly found in human oral microbiome. The aim of the present study was to understand the association of the prevalence of oral Capnocytophaga species with oral hygiene and periodontal inflammation. A total of 136 patients (median age 72 years) who visited the Hiroshima University Hospital (Hiroshima, Japan) between April 2021 and June 2023 were enrolled. Swab samples were obtained from the tongue surface. DNA from Capnocytophaga species (C. ochracea and C. sputigena) was detected by real-time PCR analysis. Dental plaque accumulation was observed to assess the oral hygiene condition of participants. Additionally, clinical periodontal inflammation was assessed with periodontal inflamed surface area (PISA) scores. Clinical confounding factors such as age, sex, lifestyle-related disease, remaining teeth and denture wearing between Capnocytophaga species-positive and -negative groups were adjusted with a propensity score matching method. Mann-Whitney U and χ2 or Fisher's exact test were employed for statistical analysis. The prevalence rate was 67.6% for oral C. ochracea and 83.1% for C. sputigena. C. ochracea-positive participants showed significantly higher plaque control record scores (an indicator of dental plaque accumulation) than C. ochracea-negative participants (P=0.03). Additionally, C. ochracea/C. sputigena dual-positive participants exhibited significantly higher plaque control record and PISA scores than non-dual-positive participants (P=0.01 and P=0.04, respectively). Propensity score matching was conducted in the C. ochracea/C. sputigena dual-positive group and the non-dual-positive group for adjustment of clinical factors, resulting in 51 matched patient pairs. C. ochracea/C. sputigena dual-positive participants had significantly higher plaque control record scores than non-dual-positive participants (P=0.02). The present results suggest that the prevalence of both oral C. ochracea and C. sputigena is associated with poor oral hygiene in middle-aged and older people.

Unexpected lower level of oral periodontal pathogens in patients with high numbers of systemic diseases

Background

Periodontal disease is associated with systemic conditions such as diabetes, arthritis, and cardiovascular disease, all diseases with large inflammatory components. Some, but not all, reports show periopathogens Porphyromonas gingivialis and Tannerella forsythia at higher levels orally in people with one of these chronic diseases and in people with more severe cases. These oral pathogens are thought to be positively associated with systemic inflammatory diseases through induction of oral inflammation that works to distort systemic inflammation or by directly inducing inflammation at distal sites in the body. This study aimed to determine if, among patients with severe periodontal disease, those with multi-morbidity (or many chronic diseases) showed higher levels of periodontal pathogens.

Methods

A total of 201 adult subjects, including 84 with severe periodontal disease were recruited between 1/2017 and 6/2019 at a city dental clinic. Electronic charts supplied self-reported diseases and conditions which informed a morbidity index based on the number of chronic diseases and conditions present. Salivary composition was determined by 16S rRNA gene sequencing.

Results

As expected, patients with severe periodontal disease showed higher levels of periodontal pathogens in their saliva. Also, those with severe periodontal disease showed higher levels of multiple chronic diseases (multimorbidity). An examination of the 84 patients with severe periodontal disease revealed some subjects despite being of advanced age were free or nearly free of systemic disease. Surprisingly, the salivary microbiota of the least healthy of these 84 subjects, defined here as those with maximal multimorbidity, showed significantly lower relative numbers of periodontal pathogens, including Porphyromonas gingivalis and Tannerella Forsythia, after controlling for active caries, tobacco usage, age, and gender. Analysis of a control group with none to moderate periodontal disease revealed no association of multimorbidity or numbers of medications used and specific oral bacteria, indicating the importance of severe periodontal disease as a variable of interest.

Conclusion

The hypothesis that periodontal disease patients with higher levels of multimorbidity would have higher levels of oral periodontal pathogens is false. Multimorbidity is associated with a reduced relative number of periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia.

The role of the oral microbiome in smoking-related cardiovascular risk: a review of the literature exploring mechanisms and pathways

Cardiovascular disease is a leading cause of morbidity and mortality. Oral health is associated with smoking and cardiovascular outcomes, but there are gaps in knowledge of many mechanisms connecting smoking to cardiovascular risk. Therefore, the aim of this review is to synthesize literature on smoking and the oral microbiome, and smoking and cardiovascular risk/disease, respectively. A secondary aim is to identify common associations between the oral microbiome and cardiovascular risk/disease to smoking, respectively, to identify potential shared oral microbiome-associated mechanisms. We identified several oral bacteria across varying studies that were associated with smoking. Atopobium, Gemella, Megasphaera, Mycoplasma, Porphyromonas, Prevotella, Rothia, Treponema, and Veillonella were increased, while Bergeyella, Haemophilus, Lautropia, and Neisseria were decreased in the oral microbiome of smokers versus non-smokers. Several bacteria that were increased in the oral microbiome of smokers were also positively associated with cardiovascular outcomes including Porphyromonas, Prevotella, Treponema, and Veillonella. We review possible mechanisms that may link the oral microbiome to smoking and cardiovascular risk including inflammation, modulation of amino acids and lipids, and nitric oxide modulation. Our hope is this review will inform future research targeting the microbiome and smoking-related cardiovascular disease so possible microbial targets for cardiovascular risk reduction can be identified.

Effects of four endophytic bacteria on cadmium speciation and remediation efficiency of Sedum plumbizincicola in farmland soil

Cadmium (Cd) pollution in farmland soils severely affects agricultural production safety, thereby threatening human health. Sedum plumbizincicola is a Cd and Zn hyperaccumulator commonly used for the phytoremediation of Cd-contaminated soil. This study was aimed to improve the remediation effect of S. plumbizincicola on Cd-contaminated farmland soil and provide a theoretical basis for the enhancement of endophytic bacteria in the repair of Cd-contaminated soil with S. plumbizincicola. Four kinds of endophytic bacteria, namely Buttiauxella, Pedobacter, Aeromonas eucrenophila, and Ralstonia pickettii, were used, and soil culture experiments and pot experiments were conducted to explore the effects of endophytic bacteria on soil Cd speciation and phytoremediation efficiency of Cd-contaminated farmland soils. Under the experimental conditions, after inoculation with endophytic bacteria, the soil pH was effectively reduced, content of weak acid-extracted Cd and oxidizable Cd increased, and content of reducible Cd and residual Cd decreased. Soil Cd activity was increased, and the availability coefficient of soil Cd increased by 1.15 to 6.41 units compared with that of the control (CK₂). Compared with CK₂, the biomass of S. plumbizincicola significantly increased by 23.23-55.12%; Cd content in shoots and roots of S. plumbizincicola increased by 29.63-46.01% and 11.42-84.47%, respectively; and bioconcentration factor was 2.13 to 2.72 times that of CK₂. The Cd removal rate of S. plumbizincicola monocropping was 48.25%. When S. plumbizincicola was planted with inoculating endophytic bacteria, the Cd removal rate in the soil reached 61.18-71.49%, which was significantly higher than that of CK₂ (p < 0.05). The treatment with endophytic bacteria activated soil Cd, promoted the growth of S. plumbizincicola, increased its Cd content, and enhanced the phytoremediation of Cd-contaminated farmland soil. Therefore, endophytic bacteria can be used to improve the remediation efficiency of S. plumbizincicola in Cd-contaminated farmland soils.

Co-Infection of Oral Candida albicans and Porphyromonas gingivalis Is Associated with Active Periodontitis in Middle-Aged and Older Japanese People

Background and Objectives: Candida albicans can be detected in subgingival sites of patients with periodontitis. However, the association between oral Candida albicans and periodontitis has not been fully elucidated in Japanese adults. The aim of this study is to clarify the relationship between oral Candida albicans infection/co-infection of oral C. albicans and Porphyromonas gingivalis and periodontitis among middle-aged and older Japanese people. Materials and Methods: Eighty-six patients (mean age 70.4 years) who visited the Hiroshima University Hospital from April to September 2021 were investigated in this study. Oral swab samples were collected from the tongue surface. C. albicans and P. gingivalis DNA was detected by real-time PCR using specific DNA primer sets. C. albicans-positive participants were classified into two groups according to the presence or absence of intron insertion of C. albicans DNA by PCR analysis. Results: C. albicans was detected in 22 (25.6%) of the 86 patients. Patients in their 80s recorded a higher C. albicans-positive rate (35.3%) compared with other participants. However, there was no significant association between the C. albicans positivity rate and clinical parameters such as sex, age, systemic disease, denture use, or oral health status. Of the 22 C. albicans-positive participants, 10 participants (45.5%) had C. albicans with intron insertion; 70% of participants who had C. albicans with intron insertion exhibited ≥6 mm probing depth. C. albicans/P. gingivalis co-infection was found in 12 patients (14%). Importantly, binomial logistic regression analysis revealed that C. albicans/P. gingivalis co-infection was significantly associated with ≥6 mm periodontal pockets with bleeding on probing (p = 0.02). Conclusions: Co-infection of C. albicans and P. gingivalis is involved in active periodontitis in middle-aged and older people.

The oral microbiome in alcohol use disorder: a longitudinal analysis during inpatient treatment

Background

Alcohol use disorder (AUD)-induced disruption of oral microbiota can lead to poor oral health; there have been no studies published examining the longitudinal effects of alcohol use cessation on the oral microbiome.

Aim

To investigate the oral microbiome during alcohol cessation during inpatient treatment for AUD.

Methods

Up to 10 oral tongue brushings were collected from 22 AUD patients during inpatient treatment at the National Institutes of Health. Alcohol use history, smoking, and periodontal disease status were measured. Oral microbiome samples were sequenced using 16S rRNA gene sequencing.

Results

Alpha diversity decreased linearly during treatment across the entire cohort (P = 0.002). Alcohol preference was associated with changes in both alpha and beta diversity measures. Characteristic tongue dorsum genera from the Human Microbiome Project such as Streptococcus, Prevotella, Veillonella and Haemophilus were highly correlated in AUD. Oral health-associated genera that changed longitudinally during abstinence included Actinomyces, Capnocytophaga, Fusobacterium, Neisseria and Prevotella.

Conclusion

The oral microbiome in AUD is affected by alcohol preference. Patients with AUD often have poor oral health but abstinence and attention to oral care improve dysbiosis, decreasing microbiome diversity and periodontal disease-associated genera while improving acute oral health.

Association of oral Epstein-Barr virus with periodontal health in Japanese adults

Previous studies have demonstrated that oral Epstein-Barr virus (EBV) is associated with periodontitis. However, the relationship between periodontitis and oral EBV has not been fully elucidated by reducing the effects of confounding factors. The aim of the present study was to clarify the association between oral Epstein-Barr virus (EBV) and oral health status among middle-aged and older Japanese individuals. A total of 124 patients (46 males and 78 females; mean age, 69.2 years; age range, 35-90 years) who visited Hiroshima University Hospital between October 2018 and December 2019 were recruited into the present study. EBV DNA positivity was determined in 124 oral rinse samples using quantitative PCR. Periodontal disease-related bacteria were also detected by PCR analysis. EBV DNA was determined as positive in 16 of the 124 enrolled patients (12.9%). No significant difference was identified between EBV DNA and clinical factors (sex, age, remaining teeth, denture use, smoking or medical history). Of the 38 patients with periodontal pockets ≥6 mm, 10 were EBV DNA positive (26.3%). There was a significant association between EBV DNA positivity and probing depth (P=0.01). Additionally, a significant association was identified between bleeding on probing (BOP) and EBV DNA positivity (P=0.03). To investigate the relationship between EBV and periodontal health status, propensity score-matching was determined between participants without ≥4 mm periodontal pockets and BOP (participants with good periodontal health) and those with ≥4 mm periodontal pockets, BOP or both (participants with poor periodontal health). A total of 35 matched pairs were identified among the patients. Patients with poor periodontal health exhibited a higher EBV DNA positivity rate (25.7%) than those with good periodontal health (0.0%). Additionally, there was a significant association between EBV DNA positivity and periodontal health status (P=0.001). T. denticola-positive participants exhibited a higher EBV DNA positivity rate than negative participants (17.6 vs. 9.6%). However, there was no significant difference. The results indicated that oral EBV may be markedly associated with periodontitis in middle-aged and older Japanese individuals.

Detection of Red complex bacteria, P. gingivalis, T. denticola and T. forsythia in infected root canals and their association with clinical signs and symptoms

Aim:

This study aimed to investigate the association between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia employing polymerase chain reaction (PCR).

Materials and Methods:

Microbial samples were obtained from 60 cases with necrotic pulp with primary teeth infections. DNA extracted from samples were analyzed for endodontic pathogens by using species-specific primers.

Results:

P. gingivalis/T. denticola were detected in 15 symptomatic teeth associated with periapical lesions. T. forsythia/T. denticola were found in 16 symptomatic teeth associated with pain and swelling. P. gingivalis was detected in 9 teeth which were associated with pain, 2 with tenderness on percussion, and 15 with periapical lesions. Statistically significant associations were found between T. forsythia as well as T. denticola in relation to clinical findings of pain and swelling. (P < 0.05). Red complex bacteria showed no statistical significant association with the presence of signs and symptoms.

Conclusion:

Prevalence of P. gingivalis, T. denticola, and T. forsythia suggested association of these bacteria with symptomatic infected pulp and periradicular diseases.

An evaluation of direct PCR assays for the detection and quantification of Porphyromonas gingivalis

Porphyromonas gingivalis has been linked to the development and progression of oesophageal squamous cell carcinoma (ESCC), and is considered to be a high-risk factor for ESCC. Currently, the commonly used methods for P. gingivalis detection are culture or DNA extraction-based, which are either time and labour intensive especially for high-throughput applications. We aimed to establish and evaluate a rapid and sensitive direct quantitative polymerase chain reaction (qPCR) protocol for the detection of P. gingivalis without DNA extraction which is suitable for large-scale epidemiological studies. Paired gingival swab samples from 192 subjects undergoing general medical examinations were analysed using two direct and one extraction-based qPCR assays for P. gingivalis. Tris-EDTA buffer-based direct qPCR (TE-direct qPCR), lysis-based direct qPCR (lysis-direct qPCR) and DNA extraction-based qPCR (kit-qPCR) were used, respectively, in 192, 132 and 60 of these samples for quantification of P. gingivalis. The sensitivity and specificity of TE-direct qPCR was 95.24% and 100% compared with lysis-direct qPCR, which was 100% and 97.30% when compared with kit-qPCR; TE-direct qPCR had an almost perfect agreement with lysis-direct qPCR (κ = 0.954) and kit-qPCR (κ = 0.965). Moreover, the assay time used for TE-direct qPCR was 1.5 h. In conclusion, the TE-direct qPCR assay is a simple and efficient method for the quantification of oral P. gingivalis and showed high sensitivity and specificity compared with routine qPCR.

High Rate of Oral Candida Detection in Dependent Japanese Older People

The aim of this study was to clarify the association between oral Candida detection and the dependency status of older people. This study included 31 older people aged ≥70 years who had a certified need for long-term care or support and received care in a local day care center; it also included 27 independent older patients aged ≥70 years who visited Hiroshima University Hospital. Oral Candida was detected by a polymerase chain reaction using swab samples from the tongue surface. Oral moisture was significantly reduced in dependent older people, compared with independent older people (p = 0.003). There was a weak negative relationship between numbers of bacteria and levels of oral moisture (Spearman's rank correlation coefficient; R = -0.29, p = 0.01). Dependent older people exhibited a significantly higher rate of Candida albicans detection (35.5%) compared with independent older people (11.1%). Dependent older people also exhibited a higher rate of concurrent detection of both C. albicans and Candida glabrata (32.3%) compared with independent older people (11.1%), but this difference was not statistically significant. Thus, dependent older people may be more susceptible to oral C. albicans infection, compared with independent older people. Good oral hygiene is necessary to prevent oral Candida infection in dependent older people.