Association of Eubacterium nodatum and Treponema denticola with human periodontitis lesions

HIV Infection and Exposure Increases Cariogenic Taxa, Reduces Taxonomic Turnover, and Homogenizes Spatial Differentiation for the Supragingival Microbiome

Background

The oral microbiome comprises distinct microbial communities that colonize diverse ecological niches across the oral cavity, the composition of which are influenced by nutrient and substrate availability, host genetics, diet, behavior, age, and other diverse host and environmental factors. Unlike other densely populated human-associated microbial ecosystems (e.g., gut, urogenital), the oral microbiome is regularly and directly exposed to the external environment and is therefore likely less stable over time. Cross sectional studies of the oral microbiome capture a glimpse of this temporal dynamism, yet a full appreciation of the relative stability, robusticity, and spatial structure of the oral environment is necessary to understand the role of microbial communities in promoting health or disease.

Results

Here we investigate the spatial and temporal stability of the oral microbiome over three sampling time points in the context of HIV infection and exposure. Individual teeth were sampled from a cohort of 565 Nigerian children with varying levels of tooth decay severity (i.e., caries disease). We collected 1,960 supragingival plaque samples and characterized the oral microbiome using a metataxonomic approach targeting an approximately 478 bp region of the bacterial rpoC gene. We found that both infection and exposure to HIV have significant effects on the stability of the supragingival plaque microbiome at both the spatial and temporal scale. Specifically, we detect (1) significantly lower taxonomic turnover of the oral community among exposed and infected children compared to unexposed children, (2) we find that HIV infection homogenizes the oral community across the anterior and posterior dentition, and (3) that impaired immunity (i.e., low CD4 count) and low taxonomic turnover over time in children living with HIV is associated with higher frequency of cariogenic taxa including Streptococcus mutans.

Conclusions

Our results document substantial community fluctuations over time in children unexposed to HIV independent of oral health status. This suggests that the oral community, under typical conditions, rapidly adapts to environmental perturbations to maintain homeostasis and that long-term taxonomic rigidity is a signal of community dysfunction, potentially leading to a higher incidence of oral disease including caries.

The Peri-Implant Microbiome-A Possible Factor Determining the Success of Surgical Peri-Implantitis Treatment?

The objective was to assess the effect of peri-implantitis surgery on the peri-implant microbiome with a follow-up of one year. A total of 25 peri-implantitis patients in whom non-surgical treatment has failed to solve peri-implantitis underwent resective surgical treatment. Their peri-implant pockets were sampled prior to surgical treatment (T0) and one year post treatment (T12). The natural dentition was sampled to analyse similarities and differences with the peri-implantitis samples. Treatment success was recorded. The change in microbial relative abundance levels was evaluated. The microbiota was analysed by sequencing the amplified V3-V4 region of the 16S rRNA genes. Sequence data were binned to amplicon sequence variants that were assigned to bacterial genera. Group differences were analysed using principal coordinate analysis, Wilcoxon signed rank tests, and t-tests. Beta diversity analyses reported a significant separation between peri-implantitis and natural dentition samples on T0 and T12, along with significant separations between successfully and non-successfully treated patients. Eubacterium was significantly lower on T12 compared to T0 for the peri-implantitis samples. Treponema and Eubacterium abundance levels were significantly lower in patients with treatment success on T0 and T12 versus no treatment success. Therefore, lower baseline levels of Treponema and Eubacterium seem to be associated with treatment success of peri-implantitis surgery. This study might aid clinicians in determining which peri-implantitis cases might be suitable for treatment and give a prognosis with regard to treatment success.

Co-occurrence of periodontal lesions and dental wear in incisor and masticatory teeth in two sheep flocks in Brazil

BACKGROUND

Periodontitis and tooth wear are multifactorial diseases with distinct etiopathogenesis that affect the health, feed efficiency and welfare of sheep.

METHODS

This study evaluated the co-occurrence of tooth wear and periodontal lesions in 129 ewes from two Brazilian flocks, clinically classified the lesions and presence of dental calculus, and identified potential pathogens in the dental biofilm of 63 ewes by polymerase chain reaction.

RESULTS

Of the 129 ewes included in the study, 75 presented periodontal lesions, while all animals presented tooth wear and dental calculus. Of the animals with periodontal lesions, 16.2% had lesions in incisor teeth and 52.7% in masticatory teeth. Regarding excessive tooth wear, 38.6% had severe wear on the incisor teeth and 89.1% on the masticatory teeth. Ewes older than 36 months had a higher frequency of periodontal lesions in incisor teeth (p < 0.001) and a greater amount of dental calculus (p < 0.001), but there was no association between tooth wear and animal age. Fusobacterium nucleatum, Tannerella forsythia and Fusobacterium necrophorum predominated in periodontal lesions.

LIMITATION

This study is limited by the small sample size and lack of diagnostic imaging to assess periodontal disease.

CONCLUSION

The co-occurrence of periodontal lesions and excessive dental wear involving both the incisor and masticatory teeth suggests that although the two diseases have different aetiologies, they likely have common risk factors.

Brain abscess caused by Porphyromonas gingivalis and Eubacterium nodatum mimicking acute stroke

We described a case of a 65-year-old man with a brain abscess caused by Porphyromonas gingivalis and Eubacterium nodatum. The patient presented right central facial nerve palsy, mutism and right hemiparesis at the examination. The patient underwent a left frontal craniotomy with evacuation of the brain abscess. Specimens were collected for microbiological analysis and intravenous treatment was started with levetiracetam, dexamethasone, meropenem (1 g/8 h) and linezolid (600 mg/12 h). After identification of anaerobic bacteria the antibiotic treatment was changed to piperacillin/tazobactam (4 g/0,5 g/8 h), fulfilling 8 weeks of antibiotic with good clinical and radiological evolution.

Investigating the relationship between periodontitis and specific memory processes in the search for cognitive markers of Alzheimer's disease risk

The spontaneous retrieval deficit (SRD) hypothesis argues that individuals in the preclinical stages of Alzheimer's disease (AD) are particularly impaired in spontaneous retrieval, which manifests in reduced mind-wandering. Our main purpose was to provide novel evidence to support the SRD hypothesis by investigating, for the first time, the relationship between mind-wandering and periodontitis, the latter being the risk factor for AD. The second objective was to address the lack of deeper understanding of the relationship between oral health and specific cognitive abilities by investigating whether periodontitis would be primarily associated with memory. Sixty community-dwelling dementia-free older adults completed neuropsychological tests that focused on various cognitive abilities and a computerised task, during which mind-wandering was evaluated. Periodontal health was assessed subjectively, and through an oral examination by a qualified dentist that focused on visible periodontitis-related changes in gingival tissues and the number of periodontitis bacteria. In line with our predictions, objective and subjective symptoms of poorer periodontal health were associated with less mind-wandering, providing further support for the SRD hypothesis. Again in line with predictions, poorer periodontal health was associated with worse episodic memory, with no relationship between periodontitis and the measure targeting various cognitive abilities, from which memory was excluded.

Effect of oral gargle containing Lespedeza cuneata extract on periodontal health improvement and disease prevention: a randomized, controlled clinical trial

BACKGROUND

This study aimed to evaluate the antiplaque and antibacterial effects of a mouthwash containing Lespedeza cuneata (LC) extract through clinical periodontal disease (PD) indicators and changes in PD-causing bacteria.

METHODS

A total of 63 subjects participated in this double-blind clinical trial. Subjects were divided into two groups: 32 participants gargled with LC extract, and 31 used saline. Scaling was performed 1 week before the experiment to secure the homogeneity of the subjects' oral conditions. After gargling with 15 ml of each solution for 1 min, participants spit out the solution to remove any residual mouthwash solution. Then, PD-related bacteria were measured via the O'Leary index, plaque index (PI), and gingival index (GI). The clinical data were collected three times: before gargling, immediately after gargling, and 5 d after gargling.

RESULTS

After 5 d, the O'Leary index, PI, and GI scores were significantly reduced in the LC extract gargle group (p < 0.05). PD-inducing Gram-positive and -negative bacteria were also reduced, confirming the LC extract's effect on periodontal health improvement and disease prevention.

CONCLUSION

Mouthwash containing LC extract, a new alternative natural substance that is safe and effective, may be used to treat PD because of its ability to inhibit and prevent PD.

Effects of Eimeria acervulina infection on the luminal and mucosal microbiota of the duodenum and jejunum in broiler chickens

The intestinal disease coccidiosis, caused by Eimeria parasites, impacts nutrient absorption in broiler chickens, leading to weight gain depression and major losses in the poultry industry. To develop alternatives to antibiotics for treating infected chickens, the gut microbiota has been researched because of its association with health factors such as nutrient exchange, immune system modulation, digestive system physiology, and pathogen exclusion. The aim of this study was to determine the effect of Eimeria acervulina infection on the luminal and mucosal microbiota of both the duodenum (DuoL and DuoM) and jejunum (JejL and JejM) at multiple time points (days 3, 5, 7, 10, and 14) post-infection. 16S rRNA amplicon sequencing was utilized to characterize the microbiota and analyze differences in alpha and beta diversity between infected (IF) and control (C) birds at each time point. Alpha diversity differed between IF and C birds in DuoM and JejM microbiota. Combined with beta diversity results, DuoM microbiota appeared to be affected by infection in the longer-term, while JejM microbiota were affected in the shorter-term. Relative abundances of bacterial taxa known for short-chain fatty acid (SCFA) production, such as Lachnospiraceae, Subdoligranulum, and Peptostreptococcaceae, tended to be lower in IF birds for all four microbiota. Moreover, predicted functional abundances showed MetaCyc pathways related to SCFA production, especially butyrate, may be influenced by these differences in bacterial relative abundance. Our findings expand understanding of how Eimeria infection affects luminal and mucosal microbiota in the duodenum and jejunum, and further research on metagenomic function may provide insights on the degree of influence duodenal and jejunal bacteria have on chicken health.

A mouthwash formulated with o-cymen-5-ol and zinc chloride specifically targets potential pathogens without impairing the native oral microbiome in healthy individuals

Background

Many antimicrobial compounds in mouthwashes can have a negative impact on the oral microbiome. O-cymen-5-ol, a compound derived from a phytochemical, has a targeted mode of action and is being used as an alternative. However, its effect on the native oral microbiome is unknown.

Aim

To assess the effect of a mouthwash formulated with o-cymen-5-ol and zinc chloride on the oral microbiome of healthy individuals.

Methods

A mouthwash formulated with o-cymen-5-ol and zinc chloride was administered to a cohort of 51 volunteers for 14 days, while another cohort of 49 volunteers received a placebo. The evolution of the oral microbiome in both groups was analysed using a metataxonomic approach.

Results

Analysis of the oral microbiome showed that the mouthwash selectively targeted potential oral pathogens while maintaining the integrity of the rest of the microbiome. Specifically, the relative abundance of several potentially pathogenic bacterial taxa, namely Fusobacteriota, Prevotella, Actinomyces, Granulicatella, Abiotrophia, Lautropia, Lachnoanaerobaculum, Eubacterium (nodatum group) and Absconditabacteriales (SR1) decreased, while the growth of Rothia, a nitrate-reducing bacterium beneficial for blood pressure, was stimulated.

Conclusions

The use of o-cymen-5-ol and zinc chloride as antimicrobial agents in oral mouthwashes is a valuable alternative to classical antimicrobial agents.

The Spouses of Stroke Patients Have a Similar Oral Microbiome to Their Partners with an Elevated Risk of Stroke

Spousal members who share no genetic relatedness show similar oral microbiomes. Whether a shared microbiome increases the risk of cerebrovascular disease is challenging to investigate. The aim of this study was to compare the oral microbiota composition of poststroke patients, their partners, and controls and to compare the risk of stroke between partners of poststroke patients and controls. Forty-seven pairs of spouses and 34 control subjects were recruited for the study. Alcohol use, smoking, metabolic disease history, clinical test results, and oral health were documented. Oral microbiome samples were measured by 16S rRNA gene sequencing. The risk of stroke was measured by risk factor assessment (RFA) and the Framingham Stroke Profile (FSP). Poststroke patients and their partners exhibited higher alpha diversity than controls. Principal-coordinate analysis (PCoA) showed that poststroke patients share a more similar microbiota composition with their partners than controls. The differentially abundant microbial taxa among the 3 groups were identified by linear discriminant analysis effect size (LEfSe) analysis. The risk factor assessment indicated that partners of poststroke patients had a higher risk of stroke than controls. Spearman correlation analysis showed that Prevotellaceae was negatively associated with RFA. Lactobacillales was negatively associated with FSP, while Campilobacterota and [Eubacterium]_nodatum_group were positively associated with FSP. These results suggest that stroke risk may be transmissible between spouses through the oral microbiome, in which several bacteria might be involved in the pathogenesis of stroke.

Dual functional carbonate-hydroxyapatite nanocomposite from Pinctada maxima and egg-white for bone tissue engineering

This study aims to design a 3D carbonate-hydroxyapatite (CHA)/sago (S) based egg white (EW) microstructure with antibacterial properties to improve the performance of bone grafts for bone tissue engineering. In this study, Pinctada maxima (P. maxima) shell was used as a calcium (Ca) source in CHA synthesis. The annealing temperature of CHA at 900, 1000, and 1100 °C affected microstructural and lattice parameters, with stoichiometry 1.72-1.77, and B-type CHA was identified. CHA/S with various concentrations of EW (10 and 30 wt.%) effectively increased pore size and porosity. XRD spectra confirmed that sago and EW in CHA nanocomposite stable the crystal structure. FTIR spectrum shows protein phosphorylation in CHA nanocomposite due to PO₄^3- ion exchange. In-vitro bioactivity of CHA-S10 (MTT assay) showed increased cell viability and optical density (OD; 24-48 h) to control. Antibacterial activity of CHA-S10 and CHA/S (control) against bacteria associated with periodontal disease and bone infection (Actinobacillus actinomycetemcomitans [A. actinomycetemcomitans], Porphyromonas gingivalis [P. gingivalis], Fusobacterium nucleatum [F. nucleatum; gram negative], and Staphylococcus aureus [S. aureus; gram positive]) by disc diffusion method showed that CHA-S10 and CHA/S had strong antibacterial activity. In conclusion, EW's properties had proven the CHA/S/EW as bone grafts, effectively increasing pore size, porosity, biocompatibility, and strong antibacterial properties.

Nonsurgical Periodontal Treatment Options and Their Impact on Subgingival Microbiota

BACKGROUND

Different periodontal treatment methods (quadrant-wise debridement, scaling and root planing (Q-SRP), full-mouth scaling (FMS), full-mouth disinfection (FMD), and FMD with adjuvant erythritol air-polishing (FMDAP)) were applied in periodontitis patients (stage III/IV). The study objective (substudy of ClinicalTrials.gov Identifier: NCT03509233) was to compare the impact of treatments on subgingival colonization.

METHODS

Forty patients were randomized to the treatment groups. Periodontal parameters and subgingival colonization were evaluated at baseline and 3 and 6 months after treatment.

RESULTS

Positive changes in clinical parameters were recorded in every treatment group during the 3-month follow-up period, but did not always continue. In three groups, specific bacteria decreased after 3 months; however, this was associated with a renewed increase after 6 months (FMS: Porphyromonas gingivalis; FMD: Eubacterium nodatum, Prevotella dentalis; and FMDAP: uncultured Prevotella sp.).

CONCLUSIONS

The benefit of all clinical treatments measured after 3 months was associated with a decrease in pathogenic bacteria in the FMS, FMD, and FMDAP groups. However, after 6 months, we observed further improvement or some stagnation in clinical outcomes accompanied by deterioration of the microbiological profile. Investigating the subgingival microbiota might help appraise successful periodontal treatment and implement individualized therapy.

Hypotensive effect of captopril on deoxycorticosterone acetate-salt-induced hypertensive rat is associated with gut microbiota alteration

The role of the gut microbiota in various metabolic diseases has been widely studied. This study aims to test the hypothesis that gut microbiota dysbiosis is associated with DOCA-salt-induced hypertension, while captopril, an antihypertensive drug, is able to rebalance the gut microbiota alterations caused by hypertension. Treatment with captopril resulted in an approximate 32 mmHg reduction in systolic blood pressure (162.57 vs. 194.61 mmHg) in DOCA-salt-induced hypertensive rats, although it was significantly higher than that in SHAM rats (136.10 mmHg). Moreover, the nitric oxide (NO) level was significantly increased (20.60 vs. 6.42 µM) while the angiotensin II (Ang II) content (42.40 vs. 59.47 pg/ml) was attenuated nonsignificantly by captopril treatment in comparison to those of DOCA-salt-induced hypertensive rats. The introduction of captopril significantly decreased the levels of tumor necrosis factor-α (TNF-ɑ) and interleukin-6 (IL-6). Hypertrophy and fibrosis in kidneys and hearts were also significantly attenuated by captopril. Furthermore, gut microbiota dysbiosis was observed in DOCA-salt-induced hypertensive rats. The abundances of several phyla and genera, including Proteobacteria, Cyanobacteria, Escherichia-Shigella, Eubacterium nodatum and Ruminococcus, were higher in DOCA-salt-induced hypertensive rats than in SHAM rats, while these changes were reversed by captopril treatment. Of particular interest, the genera Bifidobacterium and Akkermansia, reported as beneficial bacteria in the gut, were abundant in only hypertensive rats treated with captopril. These results provide evidence that captopril has the potential to rebalance the dysbiotic gut microbiota of DOCA-salt-induced hypertensive rats, suggesting that the alteration of the gut flora by captopril may contribute to the hypotensive effect of this drug.

In vitro bioactivity of 3D microstructure hydroxyapatite/collagen based-egg white as an antibacterial agent

The present study aims to design 3D scaffold hydroxyapatite (HA)/collagen (Coll) based egg-white (EW) as antibacterial properties. The calcium source in HA synthesis derived from the Pinctada maxima shell cultivated on Bali Island has proven biocompatibility, and the compressive strength exceeded human bone. HA synthesis by precipitation with heat treatment in oven-dried at 80°C (HA-80) and annealed at 900°C (HA-900), has crystallinity 48% and 85%, respectively, were used for scaffold design. The physicochemical properties of X-ray diffractometer spectra showed that increasing temperature affected the crystallinity and HA phase formed. Furthermore, the crystal structure of HA changed in nanocomposite due to the substitution of Coll and EW, and the Fourier transform infrared spectroscopy spectra confirmed that the absorption peak of the phosphate group (1027-1029 cm^-1 ) decreased intensity, presumably by protein binding of EW and Coll. The cell viability of HA/Coll/EW in 24, 48, and 72 h incubation period was 112.34 ± 4.36, 104.89 ± 3.41, 72.88 ± 6.85, respectively. The decreases of cell viability due to high cell density and reduced nutrients in wells. Antibacterial activity of HA/Col/EW exhibited a strong zone of inhibition against bacteria causing periodontitis; Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Staphylococcus aureus.

Diversity of Oral Microbiome of Women From Urban and Rural Areas of Indonesia: A Pilot Study

Objective: The studies on the influence of geographical and socio-economic factors on the oral microbiome remain underrepresented. The Indonesia basic health research (RISKESDAS) 2018, showed an increasing trend in non-communicable diseases compared with the previous report in 2013. The prevalence of diabetes, heart disease, hypertension, and obesity are reported to be higher in urban areas than in rural areas. Interestingly, non-communicable diseases were found to be more prevalent in women than men. This pilot study aimed to examine the oral health and oral microbiome derived from tongue samples of healthy Indonesian women from urban and rural areas. Methods: Twenty women aged 21-47 years old from West Jakarta, residents of DKI Jakarta (n = 10) as representative of the urban area, and residents of Ende, Nangapanda, East Nusa Tenggara (n = 10) as representative of the rural area were recruited for this pilot study. The participants were evaluated by the Simplified Oral Hygiene Index (OHI-S) according to the criteria of Greene and Vermillion and divided into three groups. High-throughput DNA sequencing was performed on an Illumina iSeq 100 platform. Results: The principal component analysis displayed a marked difference in the bacterial community profiles between the urban and rural localities. The presence of manifest was associated with increased diversity and an altered oral bacterial community profile in the urban women. Two bacterial taxa were present at significantly higher levels (adjusted p < 0.01) in the urban oral microflora (Genus Prevotella and Leptotricia) could account for this difference irrespective of the individual oral hygiene status. The linear discriminant analysis effect size (LEfSe) analysis revealed several distinct urban biomarkers. At the species level, Leptotrichia wadei, Prevotella melaninogenica, Prevotella jejuni, and P. histicola, show an excellent discriminatory potential for distinguishing the oral microflora in women between urban and rural areas. Further, using SparCC co-occurrence network analysis, the co-occurrence pattern in the dominant core oral microbiome assembly was observed to be specific to its ecological niche between two populations. Conclusions: This is the first pilot study demonstrating the characterization of the oral microbiome in Indonesian women in urban and rural areas. We found that the oral microbiome in women displays distinct patterns consistent with geographic locality. The specific characterization of the microbiota of Indonesian women is likely linked to geographical specific dietary habits, cultural habits, and socio-economic status or the population studied.

Metabolic activity of hydro-carbon-oxo-borate on a multispecies subgingival periodontal biofilm: a short communication

Objective

This study evaluated the metabolic activity of hydro-carbon-oxo-borate complex (HCOBc) on a multispecies subgingival biofilm as well as its effects on cytotoxicity.

Materials and methods

The subgingival biofilm with 32 species related to periodontitis was formed in the Calgary Biofilm Device (CBD) for 7 days. Two different therapeutic schemes were adopted: (1) treatment with HCOBc, 0.12% chlorhexidine (CHX), and negative control group (without treatment) from day 3 until day 6, two times a day for 1 min each time, totaling 8 treatments and (2) a 24-h treatment on a biofilm grown for 6 days. After 7 days of formation, biofilm metabolic activity was determined by colorimetry assay, and bacterial counts and proportions of complexes were determined by DNA-DNA hybridization. Both substances’ cytotoxicity was evaluated by cell viability (XTT assay) and clonogenic survival assay on ovary epithelial CHO-K1 cells and an osteoblast precursor from calvaria MC3T3-E1 cells.

Results

The first treatment scheme resulted in a significant reduction in biofilm’s metabolic activity by means of 77% by HCOBc and CHX treatments versus negative control. The total count of 11 and 25 species were decreased by treatment with hydro-carbon-oxo-borate complex and CHX, respectively, compared with the group without treatment (p < 0.05), highlighting a reduction in the levels of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Fusobacterium periodontium. CHX significantly reduced the count of 10 microorganisms compared to the group treated with HCOBc (p < 0.05). HCOBc and CHX significantly decreased the pathogenic red-complex proportion compared with control-treated biofilm, and HCOBc had even a more significant effect on the red complex than CHX had (p ≤ 0.05). For the second treatment scheme, HCOBc complex and CHX significantly decreased 61 and 72% of control biofilms’ metabolic activity and the counts of 27 and 26 species, respectively. HCOBc complex did not significantly affect the proportions of formed biofilms, while CHX significantly reduced red, orange, and yellow complexes. Both substances exhibited similar cytotoxicity results.

Conclusions

This short communication suggested that the HCOBc complex reduced a smaller number of bacterial species when compared to chlorhexidine during subgingival biofilm formation, but it was better than chlorhexidine in reducing red-complex bacterial proportions. Although HCOBc reduced the mature 6-day-old subgingival multispecies biofilms, it did not modify bacterial complexes’ ratios as chlorhexidine did on the biofilms mentioned above. Future in vivo studies are needed to validate these results.

Clinical relevance

HCOBc complex could be used to reduce red-complex periodontal bacterial proportions.

Dietary inflammatory potential in relation to the gut microbiome: results from a cross-sectional study

Diet has direct and indirect effects on health through inflammation and the gut microbiome. We investigated total dietary inflammatory potential via the literature-derived index (Dietary Inflammatory Index (DII®)) with gut microbiota diversity, composition and function. In cancer-free patient volunteers initially approached at colonoscopy and healthy volunteers recruited from the medical centre community, we assessed 16S ribosomal DNA in all subjects who provided dietary assessments and stool samples (n 101) and the gut metagenome in a subset of patients with residual fasting blood samples (n 34). Associations of energy-adjusted DII scores with microbial diversity and composition were examined using linear regression, permutational multivariate ANOVA and linear discriminant analysis. Spearman correlation was used to evaluate associations of species and pathways with DII and circulating inflammatory markers. Across DII levels, α- and β-diversity did not significantly differ; however, Ruminococcus torques, Eubacterium nodatum, Acidaminococcus intestini and Clostridium leptum were more abundant in the most pro-inflammatory diet group, while Akkermansia muciniphila was enriched in the most anti-inflammatory diet group. With adjustment for age and BMI, R. torques, E. nodatum and A. intestini remained significantly associated with a more pro-inflammatory diet. In the metagenomic and fasting blood subset, A. intestini was correlated with circulating plasminogen activator inhibitor-1, a pro-inflammatory marker (rho = 0·40), but no associations remained significant upon correction for multiple testing. An index reflecting overall inflammatory potential of the diet was associated with specific microbes, but not overall diversity of the gut microbiome in our study. Findings from this preliminary study warrant further research in larger samples and prospective cohorts.

Exploring the putative interactions between chronic kidney disease and chronic periodontitis

Chronic kidney disease (CKD) and chronic periodontitis (CP) are both common diseases, which are found disproportionately comorbid with each other and have been reported to have a detrimental effect on the progression of each respective disease. They have an overlap in risk factors and both are a source of systemic inflammation along with a wide selection of immunological and non-specific effects that can affect the body over the lifespan of the conditions. Previous studies have investigated the directionality of the relationship between these two diseases; however, there is a lack of literature that has examined how these diseases may be interacting at the localized and systemic level. This review discusses how oral microorganisms have the ability to translocate and have distal effects and provides evidence for microbial involvement in a systemic disease. Furthermore, it summarizes the reported local and systemic effects of CKD and CP and discusses how the interaction of these effects may be responsible for directionality associations reported.

Active matrix metalloproteinase-8 and periodontal bacteria-interlink between periodontitis and inflammatory bowel disease?

BACKGROUND

The aim of this study was the investigation of concentration and prevalence of selected periodontal pathogenic bacteria and concentration of active matrix metalloproteinase-8 (aMMP-8) within a group of patients with inflammatory bowel diseases (IBD) and to compare the results with a group of healthy control subjects (HC).

METHODS

Fifty-nine IBD patients with Crohn`s disease (CD, n = 30) or ulcerative colitis (UC, n = 29) and 59 HC were included in this cross-sectional study. Based on periodontal probing depth (PD) and clinical attachment level (CAL), periodontitis was classified as healthy/mild, moderate, or severe. aMMP-8 was analyzed from gingival crevicular fluid using enzyme linked immunosorbent assay. Eleven selected periodontal pathogenic bacteria were analyzed in subgingival plaque samples using polymerase chain reaction.

RESULTS

IBD patients showed higher CAL (P < 0.01), more severe periodontitis (P = 0.04), gingival bleeding (P < 0.01) and aMMP-8 concentration (P < 0.01) than HC. Only in CD, increasing severity of periodontitis was associated with an increase in aMMP-8 concentration (P = 0.02). The prevalences of Eubacterium nodatum and Eikenella corrodens were significantly lower in IBD compared to HC (P = 0.01). Additionally, the prevalence of Eikenella corrodens was significantly higher in CD compared to the UC group (P = 0.04). Further statistically significant differences in selected bacteria between IBD and HC or CD and UC groups could not be found (P > 0.05).

CONCLUSIONS

The results reveal changes in host immune response of IBD patients in terms of aMMP-8. Only in CD increasing aMMP-8 was associated with severity of periodontal disease. The role of periodontal pathogenic bacteria in the interrelationship between IBD and periodontitis remains unclear.

Periodontal Antibodies and All-Cause and Cardiovascular Disease Mortality

Periodontitis is positively linked to cardiovascular disease (CVD), diabetes, cancer, and increased mortality. Empirically derived clusters of IgG antibodies against 19 selected periodontal microorganisms have been associated with hyperglycemia. We further investigated associations between these serum IgG antibody clusters and all-cause and CVD mortality in a representative US population. Participants free of CVD and cancer and aged ≥40 y at baseline (N = 6,491) from the Third National Health and Nutrition Examination Survey (1988 to 1994) were followed up until December 31, 2011. Antibodies were categorized into 4 clusters: red-green, orange-red, yellow-orange, and orange-blue. Over a 23-y follow-up, 2,702 deaths occurred, including 810 CVD-related deaths. In fully adjusted Cox proportional hazard models, the red-green cluster was positively associated with all-cause mortality (tertile 3 vs. tertile 1: hazard ratio [HR] = 1.43, 95% CI = 1.08 to 1.90, P = 0.015). The yellow-orange cluster was inversely associated with all-cause mortality (tertile 3 vs. tertile 1: HR = 0.78, 95% CI = 0.63 to 0.97, P = 0.028) and CVD mortality (tertile 2 vs. tertile 1: HR = 0.57, 95% CI = 0.42 to 0.77, P = 0.005). The orange-blue cluster (composed of antibodies against Eubacterium nodatum and Actinomyces naeslundii) was inversely associated with all-cause mortality (tertile 3 vs. tertile 1: HR = 0.65, 95% CI = 0.55 to 0.78, P < 0.0001) and CVD mortality (tertile 3 vs. tertile 1: HR = 0.65, 95% CI = 0.47 to 0.88, P = 0.007). These antibodies could predict prognosis or be potential intervention targets to prevent systemic effects of periodontal disease if further studies establish a causal relationship.

Dental hypofunction alters subgingival microorganisms: a pilot study

BACKGROUND

The aim of this study was to evaluate dental plaque compositions, vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF) 1-alpha levels in gingival crevicular fluid (GCF) at hypofunctional and normofunctional teeth in healthy individuals and chronic periodontitis patients.

METHODS

Sixty systemically healthy individuals were enrolled. Study groups were: group 1 hypofunctional healthy group (group 1, N.=15); group 2 hypofunctional periodontitis group (group 2, N.=15); group 3 normofunctional healthy group (group 3, N.=15); and group 4 normofunctional periodontitis group (group 4, N.=15). Clinical periodontal measurements (plaque index, gingival index and clinical attachment level) were recorded. Dental plaque and GCF samples were taken. VEGF and HIF 1-alpha levels in GCF were determined. Subgingival plaque samples were evaluated for 11 different bacterial species as, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Campylobacter rectus, Eubacterium nodatum, Eikenella corrodens and Capnocytophaga species.

RESULTS

Tannerella forsythia, Peptostreptococcus micros, Eubacterium nodatum levels decreased in hypofunctional healthy and periodontitis groups (P<0.05). Porphyromonas gingivalis levels increased in hypofunctional healthy group and decreased in hypofunctional periodontitis group (P<0.05). There was also a decrease in Eikenella corrodens levels in hypofunctional periodontitis group (P<0.05). There were no difference regarding the Aggregatibacter actinomycetemcomitans, Capnocytophaga spp., Prevotella intermedia and Fusobacterium nucleatum levels among the groups (P>0.05). VEGF and HIF-1α levels in both GCF and serum samples were also similar (P>0.05).

CONCLUSIONS

Within the limits of this study, the authors found that the levels of four significant bacterial strains were decreased in both hypofunctional healthy and hypofunctional periodontitis groups compared to normofunctional equivalents. Though not evaluated in this study, this situation could be due to periodontal ligament atrophy and related physiological alterations.

Serum IgG Antibodies against Periodontal Microbes and Cancer Mortality

INTRODUCTION

Periodontitis is a chronic inflammatory condition initiated by microorganisms and is positively linked to systemic conditions such as cancer, cardiovascular disease, and diabetes mellitus.

OBJECTIVES

To prospectively investigate associations between empirically derived clusters of IgG antibodies against 19 selected periodontal microorganisms and cancer mortality in a representative sample of the US population.

METHODS

We evaluated 6,491 participants aged ≥40 y from the Third National Health and Nutrition Examination Survey (1988 to 1994), who had complete data on IgG antibody titers against 19 selected periodontal microorganisms and were free of cardiovascular disease and cancer. In a prior study, antibodies were categorized into 4 mutually exclusive groups via cluster analysis: red-green, orange-red, yellow-orange, and orange-blue. Cluster scores were estimated by summing z scores of the antibody titers making up each cluster. Participants were followed up to death until December 31, 2011. Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% CIs for all-cancer mortality by tertiles of cluster scores.

RESULTS

During follow-up for a median of 15.9 y, there were 2,702 deaths (31.3%), including 631 cancer-related deaths (8.1%). After adjusting for multiple confounders, the orange-blue cluster was inversely associated with cancer mortality (tertile 2 vs. tertile 1: HR = 0.67, 95% CI = 0.54 to 0.84; tertile 3 vs tertile 1: HR = 0.62, 95% CI = 0.46 to 0.84). The association between the yellow-orange cluster and all-cancer mortality was also inverse but not significant, and the orange-red cluster and the red-green cluster were not associated with all-cancer mortality.

CONCLUSIONS

Antibodies against Eubacterium nodatum and Actinomyces naeslundii may be novel predictors of cancer mortality. If further studies establish a causal relationship between these antibodies and cancer mortality, they could be targets to prevent possible systemic effects of periodontal disease with potential interventions to raise their levels.

KNOWLEDGE TRANSFER STATEMENT

Periodontal antibodies against Eubacterium nodatum and Actinomyces naeslundii were inversely associated with cancer mortality among adults followed up for an average of 16 y. Periodontal antibodies may predict cancer mortality.

Allergic rhinitis and periodontitis among Korean adults: results from a nationwide population-based study (2013-2015)

BACKGROUND

The purpose of this study was to examine whether allergic rhinitis is associated with periodontal disease in a representative sample of elderly Korean people that was adjusted for socio-demographic factors, oral and general health behaviors, and systemic health status.

METHODS

A total of 10,643 subjects who were between 20 and 59 years of age participated in the Korean National Health and Nutrition Examination Survey and underwent cross-sectional examination. Medical history of allergic rhinitis was collected from participants by questionnaire; additionally, periodontal status was assessed using a Community Periodontal Index score of 3 or 4. Multivariate logistic regression analysis was conducted to adjust for socio-demographic variables, oral health status and behaviors, and general health status and behaviors. All analyses were performed using a complex sampling design.

RESULTS

Allergic rhinitis and periodontitis showed a significant inverse association. After adjusting for all confounders, a trend of decreasing periodontitis risk was observed as allergic rhinitis increased. The adjusted odds ratio of periodontitis was 0.79 (0.66-0.95) for patients with allergic rhinitis.

CONCLUSION

A significant inverse association between allergic rhinitis and periodontal status was demonstrated in this patient population.

The subgingival periodontal microbiota of the aging mouth

Different mechanisms have been hypothesized to explain the increase in prevalence and severity of periodontitis in older adults, including shifts in the periodontal microbiota. However, the actual impact of aging on the composition of subgingival biofilms remains unclear. In the present article, we provide an overview of the composition of the subgingival biofilm in older adults and the potential effects of age on the oral microbiome. In particular, this review covers the following topics: (i) the oral microbiota of an aging mouth; (ii) the effects of age and time on the human oral microbiome; (iii) the potential impact of inflammaging and immunosenescence in the host-oral microbiota interactions; and (iv) the relationship of the aging oral microbiota and Alzheimer's disease. Finally, we present analyses of data compiled from large clinical studies that evaluated the subgingival microbiota of periodontally healthy subjects and patients with periodontitis from a wide age spectrum (20-83 years of age).

Smoking May Lead to Marginal Bone Loss Around Non-Submerged Implants During Bone Healing by Altering Salivary Microbiome: A Prospective Study

BACKGROUND

This prospective and controlled study elucidates the impact of smoking on the salivary microbiome and its further influence on marginal bone loss (MBL) around an implant during a 3-month bone-healing period.

METHODS

Saliva samples were collected preoperatively from 20 periodontally healthy patients with single-tooth replacement in the posterior mandible (smokers [n = 10] and non-smokers [n = 10]). Sequencing of 16S recombinant RNA gene amplicons was used to characterize the salivary microbiome. Each patient received implant surgery after oral clinical assessment, and MBL around the implant was measured during a 3-month healing period.

RESULTS

In total, 871,389 sequences were compared against the Human Oral Microbiome Database for bacterial identification. Microbial signatures of smokers exhibited lower diversity and richness, with a significant decrease in uncultured species. The phyla Gracilibacteria and Saccharibacteria showed a significant decrease in smokers. The genera Streptococcus, Lachnoanaerobaculum, Stomatobaculum, and Eubacterium were significantly increased in smokers, whereas Selenomonas, Selenomonas [G-3], and Catonella were significantly decreased. Specifically, Porphyromonas gingivalis was significantly more abundant in smokers, which was positively related to the severity of MBL during bone healing.

CONCLUSIONS

Smoking shapes the salivary microbiome in states of clinical health, and further may influence MBL during bone healing by creating high at-risk-for-harm communities. Understanding of the distinctly divergent oral microbiome in smokers and non-smokers is a base for personalized therapeutics for this high-risk cohort and also a base for further study on the pathologic mechanisms.

Molecular-level evaluation of selected periodontal pathogens from subgingival regions in canines and humans with periodontal disease

Dogs commonly serve as a model for various human conditions, including periodontal diseases. The aim of this study was to identify the anaerobic bacteria that colonize the subgingival areas in dogs and humans by using rapid real-time polymerase chain reaction (RT-PCR)-based tests and to compare the results obtained in each species. Bacterial microflora evaluations, both quantitative and qualitative, were performed by applying ready-made tests on twelve dogs and twelve humans. Five samples were collected from each subject's deepest gingival pockets and joined to form a collective sample. The results of the study revealed interspecies similarities in the prevalences of Porphyromonas (P.) gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum. Red complex bacteria comprised the largest portion of the studied bacterial complexes in all study groups, with P. gingivalis being the most commonly isolated bacterium. The results show similarities in the prevalence of bacterial microflora in dogs and humans. Microbiological analysis of gingival pockets by using rapid real-time PCR-based tests in clinical practice, both veterinary and human, can facilitate the choice of appropriate pharmacological treatment and can provide a basis for subsequent verification of the treatment's effectiveness.

Signature of Microbial Dysbiosis in Periodontitis

Periodontitis is driven by disproportionate host inflammatory immune responses induced by an imbalance in the composition of oral bacteria; this instigates microbial dysbiosis, along with failed resolution of the chronic destructive inflammation. The objectives of this study were to identify microbial signatures for health and chronic periodontitis at the genus level and to propose a model of dysbiosis, including the calculation of bacterial ratios. Published sequencing data obtained from several different studies (196 subgingival samples from patients with chronic periodontitis and 422 subgingival samples from healthy subjects) were pooled and subjected to a new microbiota analysis using the same Visualization and Analysis of Microbial Population Structures (VAMPS) pipeline, to identify microbiota specific to health and disease. Microbiota were visualized using CoNet and Cytoscape. Dysbiosis ratios, defined as the percentage of genera associated with disease relative to the percentage of genera associated with health, were calculated to distinguish disease from health. Correlations between the proposed dysbiosis ratio and the periodontal pocket depth were tested with a different set of data obtained from a recent study, to confirm the relevance of the ratio as a potential indicator of dysbiosis. Beta diversity showed significant clustering of periodontitis-associated microbiota, at the genus level, according to the clinical status and independent of the methods used. Specific genera (Veillonella, Neisseria, Rothia, Corynebacterium, and Actinomyces) were highly prevalent (>95%) in health, while other genera (Eubacterium, Campylobacter, Treponema, and Tannerella) were associated with chronic periodontitis. The calculation of dysbiosis ratios based on the relative abundance of the genera found in health versus periodontitis was tested. Nonperiodontitis samples were significantly identifiable by low ratios, compared to chronic periodontitis samples. When applied to a subgingival sample set with well-defined clinical data, the method showed a strong correlation between the dysbiosis ratio, as well as a simplified ratio (Porphyromonas, Treponema, and Tannerella to Rothia and Corynebacterium), and pocket depth. Microbial analysis of chronic periodontitis can be correlated with the pocket depth through specific signatures for microbial dysbiosis.IMPORTANCE Defining microbiota typical of oral health or chronic periodontitis is difficult. The evaluation of periodontal disease is currently based on probing of the periodontal pocket. However, the status of pockets "on the mend" or sulci at risk of periodontitis cannot be addressed solely through pocket depth measurements or current microbiological tests available for practitioners. Thus, a more specific microbiological measure of dysbiosis could help in future diagnoses of periodontitis. In this work, data from different studies were pooled, to improve the accuracy of the results. However, analysis of multiple species from different studies intensified the bacterial network and complicated the search for reproducible microbial signatures. Despite the use of different methods in each study, investigation of the microbiota at the genus level showed that some genera were prevalent (up to 95% of the samples) in health or disease, allowing the calculation of bacterial ratios (i.e., dysbiosis ratios). The correlation between the proposed ratios and the periodontal pocket depth was tested, which confirmed the link between dysbiosis ratios and the severity of the disease. The results of this work are promising, but longitudinal studies will be required to improve the ratios and to define the microbial signatures of the disease, which will allow monitoring of periodontal pocket recovery and, conceivably, determination of the potential risk of periodontitis among healthy patients.

Systemic antibiotics in the treatment of periodontitis

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.

Effect of smokeless tobacco products on human oral bacteria growth and viability

To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32-2.14 log₁₀ fold, while 14 strains demonstrated enhanced growth of 0.3-1.76 log₁₀ fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3-2.11 log₁₀ fold, 18 strains showed enhanced growth of 0.3-0.97 log₁₀ fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3-2.96 log₁₀ fold, 8 strains showed enhanced growth of 0.3-1.0 log₁₀ fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1-66.5% decrease for 4 strains at 1 mg/ml, 20.3-85.7% decrease for 10 strains at 10 mg/ml, 20.0-93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 μg/ml; while the growth of P. micros was enhanced 0.31-0.54 log₁₀ fold; the growth of Veillonella parvula was repressed 0.33-0.36 log₁₀ fold; and the cell viabilities of 2 strains decreased 56.6-69.9%. The results demonstrate that STAEs affected the growth of some types of oral bacteria, which may affect the healthy ecological balance of oral bacteria in humans. On the other hand, TSNAs did not significantly affect the growth of the oral bacteria.

Subgingival microbiome in patients with healthy and ailing dental implants

Dental implants are commonly used to replace missing teeth. However, the dysbiotic polymicrobial communities of peri-implant sites are responsible for peri-implant diseases, such as peri-implant mucositis and peri-implantitis. In this study, we analyzed the microbial characteristics of oral plaque from peri-implant pockets or sulci of healthy implants (n = 10), peri-implant mucositis (n = 8) and peri-implantitis (n = 6) sites using pyrosequencing of the 16S rRNA gene. An increase in microbial diversity was observed in subgingival sites of ailing implants, compared with healthy implants. Microbial co-occurrence analysis revealed that periodontal pathogens, such as Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia, were clustered into modules in the peri-implant mucositis network. Putative pathogens associated with peri-implantitis were present at a moderate relative abundance in peri-implant mucositis, suggesting that peri-implant mucositis an important early transitional phase during the development of peri-implantitis. Furthermore, the relative abundance of Eubacterium was increased at peri-implantitis locations, and co-occurrence analysis revealed that Eubacterium minutum was correlated with Prevotella intermedia in peri-implantitis sites, which suggests the association of Eubacterium with peri-implantitis. This study indicates that periodontal pathogens may play important roles in the shifting of healthy implant status to peri-implant disease.

Functional signatures of oral dysbiosis during periodontitis progression revealed by microbial metatranscriptome analysis

BACKGROUND

Periodontitis is a polymicrobial biofilm-induced inflammatory disease that affects 743 million people worldwide. The current model to explain periodontitis progression proposes that changes in the relative abundance of members of the oral microbiome lead to dysbiosis in the host-microbiome crosstalk and then to inflammation and bone loss. Using combined metagenome/metatranscriptome analysis of the subgingival microbiome in progressing and non-progressing sites, we have characterized the distinct molecular signatures of periodontitis progression.

METHODS

Metatranscriptome analysis was conducted on samples from subgingival biofilms from progressing and stable sites from periodontitis patients. Community-wide expression profiles were obtained using Next Generation Sequencing (Illumina). Sequences were aligned using 'bowtie2' against a constructed oral microbiome database. Differential expression analysis was performed using the non-parametric algorithm implemented on the R package 'NOISeqBio'. We summarized global functional activities of the oral microbial community by set enrichment analysis based on the Gene Ontology (GO) orthology.

RESULTS

Gene ontology enrichment analysis showed an over-representation in the baseline of active sites of terms related to cell motility, lipid A and peptidoglycan biosynthesis, and transport of iron, potassium, and amino acids. Periodontal pathogens (Tannerella forsythia and Porphyromonas gingivalis) upregulated different TonB-dependent receptors, peptidases, proteases, aerotolerance genes, iron transport genes, hemolysins, and CRISPR-associated genes. Surprisingly, organisms that have not been usually associated with the disease (Streptococcus oralis, Streptococcus mutans, Streptococcus intermedius, Streptococcus mitis, Veillonella parvula, and Pseudomonas fluorenscens) were highly active transcribing putative virulence factors. We detected patterns of activities associated with progression of clinical traits. Among those we found that the profiles of expression of cobalamin biosynthesis, proteolysis, and potassium transport were associated with the evolution towards disease.

CONCLUSIONS

We identified metabolic changes in the microbial community associated with the initial stages of dysbiosis. Regardless of the overall composition of the community, certain metabolic signatures are consistent with disease progression. Our results suggest that the whole community, and not just a handful of oral pathogens, is responsible for an increase in virulence that leads to progression.

TRIAL REGISTRATION

NCT01489839, 6 December 2011.

Point-of-care detection of Tannerella forsythia using an antigen-antibody assisted dielectrophoretic impedance measurement method

The importance of periodontal treatment planning based on diagnosis with clinical detection of periodontal pathogens has been well recognized. However, reliable detection and quantification methods that can be conveniently used at chair-side have yet to be developed. This study aimed to evaluate the clinical use of a novel apparatus which uses an antigen-antibody reaction assisted dielectrophoretic impedance measurement (AA-DEPIM) for the detection of a prominent periodontal pathogen, Tannerella forsythia. A total of 15 patients with a clinical diagnosis of chronic periodontitis, three periodontally healthy volunteers and two with gingivitis were subjected to clinical and microbiological examinations. Saliva samples were analyzed for the presence of T. forsythia using AA-DEPIM, PCR-Invader and real-time PCR methods. The measurement values for total bacteria and T. forsythia using the prototype AA-DEPIM apparatus were significantly greater in periodontitis group than those in healthy/gingivitis group. Using the AA-DEPIM apparatus with tentative cut-off values, T. forsythia was detected for 14 (12 with periodontitis and 2 either healthy or with gingivitis) out of 20 individuals. The measurement for the detection of T. forsythia by the AA-DEPIM method showed a significant positive correlation with the detection by PCR-Invader (r = 0.541, p = 0.01) and the real-time PCR method (r = 0.834, p = 0.01). When the PCR-Invader method was used as a reference, the sensitivity and specificity of the AA-DEPIM method were 76.5% and 100%, respectively. The results suggested that the AA-DEPIM method has potential to be used for clinically evaluating salivary presence of T. forsythia at chair-side.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000012181.

A Filifactor alocis-centered co-occurrence group associates with periodontitis across different oral habitats

Periodontitis is a highly prevalent polymicrobial disease worldwide, yet the synergistic pattern of the multiple oral pathogens involved is still poorly characterized. Here, saliva, supragingival and subgingival plaque samples from periodontitis patients and periodontally healthy volunteers were collected and profiled with 16S rRNA gene pyrosequencing. Different oral habitats harbored significantly different microbiota, and segregation of microbiota composition between periodontitis and health was observed as well. Two-step redundancy analysis identified twenty-one OTUs, including Porphyromonas gingivalis, Tannerella forsythia and Filifactor alocis, as potential pathogens that were significantly associated with periodontitis and with two periodontitis diagnostic parameters (pocket depth and attachment loss) in both saliva and supragingival plaque habitats. Interestingly, pairwise correlation analysis among the 21 OTUs revealed that Filifactor alocis was positively correlated with seven other putative pathogens (R > 0.6, P < 0.05), forming a co-occurrence group that was remarkably enriched in all three habitats of periodontitis patients. This bacterial cluster showed a higher diagnostic value for periodontitis than did any individual potential pathogens, especially in saliva. Thus, our study identified a potential synergistic ecological pattern involving eight co-infecting pathogens across various oral habitats, providing a new framework for understanding the etiology of periodontitis and developing new diagnoses and therapies.

High-resolution taxonomic profiling of the subgingival microbiome for biomarker discovery and periodontitis diagnosis

The oral microbiome plays a key role for caries, periodontitis, and systemic diseases. A method for rapid, high-resolution, robust taxonomic profiling of subgingival bacterial communities for early detection of periodontitis biomarkers would therefore be a useful tool for individualized medicine. Here, we used Illumina sequencing of the V1-V2 and V5-V6 hypervariable regions of the 16S rRNA gene. A sample stratification pipeline was developed in a pilot study of 19 individuals, 9 of whom had been diagnosed with chronic periodontitis. Five hundred twenty-three operational taxonomic units (OTUs) were obtained from the V1-V2 region and 432 from the V5-V6 region. Key periodontal pathogens like Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia could be identified at the species level with both primer sets. Principal coordinate analysis identified two outliers that were consistently independent of the hypervariable region and method of DNA extraction used. The linear discriminant analysis (LDA) effect size algorithm (LEfSe) identified 80 OTU-level biomarkers of periodontitis and 17 of health. Health- and periodontitis-related clusters of OTUs were identified using a connectivity analysis, and the results confirmed previous studies with several thousands of samples. A machine learning algorithm was developed which was trained on all but one sample and then predicted the diagnosis of the left-out sample (jackknife method). Using a combination of the 10 best biomarkers, 15 of 17 samples were correctly diagnosed. Training the algorithm on time-resolved community profiles might provide a highly sensitive tool to detect the onset of periodontitis.

Serum IgG antibody levels to periodontal microbiota are associated with incident Alzheimer disease

Background

Periodontitis and Alzheimer disease (AD) are associated with systemic inflammation. This research studied serum IgG to periodontal microbiota as possible predictors of incident AD.

Methods

Using a case-cohort study design, 219 subjects (110 incident AD cases and 109 controls without incident cognitive impairment at last follow-up), matched on race-ethnicity, were drawn from the Washington Heights-Inwood Columbia Aging Project (WHICAP), a cohort of longitudinally followed northern Manhattan residents aged >65 years. Mean follow-up was five years (SD 2.6). In baseline sera, serum IgG levels were determined for bacteria known to be positively or negatively associated with periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans Y4, Treponema denticola, Campylobacter rectus, Eubacterium nodatum, and Actinomyces naeslundii genospecies-2). In all analyses, we used antibody threshold levels shown to correlate with presence of moderate-severe periodontitis.

Results

Mean age was 72 years (SD 6.9) for controls, and 79 years (SD 4.6) for cases (p<0.001). Non-Hispanic Whites comprised 26%, non-Hispanic Blacks 27%, and Hispanics 48% of the sample. In a model adjusting for baseline age, sex, education, diabetes mellitus, hypertension, smoking, prior history of stroke, and apolipoprotein E genotype, high anti-A. naeslundii titer (>640 ng/ml, present in 10% of subjects) was associated with increased risk of AD (HR = 2.0, 95%CI: 1.1–3.8). This association was stronger after adjusting for other significant titers (HR = 3.1, 95%CI: 1.5–6.4). In this model, high anti-E. nodatum IgG (>1755 ng/ml; 19% of subjects) was associated with lower risk of AD (HR = 0.5, 95%CI: 0.2–0.9).

Conclusions

Serum IgG levels to common periodontal microbiota are associated with risk for developing incident AD.

Subgingival microbiome in smokers and non-smokers in Korean chronic periodontitis patients

Smoking is a major environmental factor associated with periodontal diseases. However, we still have a very limited understanding of the relationship between smoking and subgingival microflora in the global population. Here, we investigated the composition of subgingival bacterial communities from the pooled plaque samples of smokers and non-smokers, 134 samples in each group, in Korean patients with moderate chronic periodontitis using 16S rRNA gene-based pyrosequencing. A total of 17,927 reads were analyzed and classified into 12 phyla, 126 genera, and 394 species. Differences in bacterial communities between smokers and non-smokers were examined at all phylogenetic levels. The genera Fusobacterium, Fretibacterium, Streptococcus, Veillonella, Corynebacterium, TM7, and Filifactor were abundant in smokers. On the other hand, Prevotella, Campylobacter, Aggregatibacter, Veillonellaceae GQ422718, Haemophilus, and Prevotellaceae were less abundant in smokers. Among species-level taxa occupying > 1% of whole subgingival microbiome of smokers, higher abundance (≥ 2.0-fold compared to non-smokers) of seven species or operational taxonomic units (OTUs) was found: Fusobacterium nucleatum, Neisseria sicca, Neisseria oralis, Corynebacterium matruchotii, Veillonella dispar, Filifactor alocis, and Fretibacterium AY349371. On the other hand, lower abundance of 11 species or OTUs was found in smokers: Neisseria elongata, six Prevotella species or OTUs, Fusobacterium canifelinum, Aggregatibacter AM420165, Selenomonas OTU, and Veillonellaceae GU470897. Species richness and evenness were similar between the groups whereas diversity was greater in smokers than non-smokers. Collectively, the results of the present study indicate that differences exist in the subgingival bacterial community between smoker and non-smoker patients with chronic moderate periodontitis in Korea, suggesting that cigarette smoking considerably affects subgingival bacterial ecology.

Microbial role in periodontitis: Have we reached the top? Some unsung bacteria other than red complex

The microbial etiology of periodontal disease has been the focus of researchers for a long time. The search for the pathogens of periodontal diseases has been underway for more than 100 years, and continues up today. Despite the increasing knowledge about oral microbiota, we are not able to implicate any one particular organism that can be considered as a candidate pathogen. In fact the term "candidate pathogen" has lost its steam with a myriad of microorganisms being incriminated from time to time. Most studies of the bacterial etiology of periodontitis have used either culture-based or targeted deoxyribonucleic acid approaches and so it is likely that pathogens remain undiscovered. The advent of 16S cloning and sequencing has facilitated identification of several uncultivable bacteria in the oral cavity. The concept that not one single organism, but several organisms contained in the biofilm orchestrating in a medley of the show appears to be more plausible. The present review highlights some lesser known bacteria associated with periodontal destruction.

Association between Serum Antibodies to Oral Microorganisms and Hyperglycemia in Adults

We conducted a cross-sectional analysis to evaluate the relationship between serum antibody titers against 19 selected oral microorganisms and measures of hyperglycemia in a large, nationally representative data set. The study population consisted of 7,848 participants from the National Health and Nutrition Examination Survey III (1988-1994) who were at least 40 yrs old, with complete serum IgG antibody data against 19 oral microorganisms. The 19 antibody titers were grouped into 4 categories via cluster analysis--orange-red, yellow-orange, orange-blue, and red-green--named to reflect predominant antibody titers against microorganisms in Socransky's classification scheme for oral microbes. Linear regression models weighted for complex survey design were used in which fasting blood glucose, fasting insulin, and HbA1c were outcomes and antibody cluster scores were exposures, adjusting for potential confounders. Higher orange-red cluster scores were associated with increased hyperglycemia, while higher orange-blue cluster scores were related with decreased hyperglycemia. A 1-unit-higher orange-red cluster score was associated with 0.46 mg/dL higher fasting blood glucose (p = .0038), and a 1-unit-higher orange-blue cluster score was associated with 0.34% lower HbA1c (p = .0257). Groups of antibody titers against periodontal microorganisms were associated with hyperglycemia independent of known risk factors.

Lessons learned and unlearned in periodontal microbiology

Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.

Comparative analysis of oral treponemes associated with periodontal health and disease

BACKGROUND

Periodontal diseases, such as periodontitis, are chronic inflammatory infections affecting the gingivae (gums), underlying connective tissues and bone that support the teeth. Oral treponemes (genus Treponema) are widely-considered to play important roles in periodontal disease etiology and pathogenesis; however, precise relationships remain to be fully established.

METHODS

A 16S rRNA clone library-based approach was used to comprehensively characterize and compare the diversity of treponeme taxa present in subgingival plaque sampled from periodontitis patients (n = 10) versus periodontitis-free controls (n = 10). 16S rRNA gene sequences were assigned to operational taxonomic units (OTUs) using a 99% identity cut-off A variety of taxonomy (OTU) and phylogeny-based statistical approaches were used to compare populations of treponeme OTUs present in both subject groups.

RESULTS

A total of 615 plasmid clones containing ca. 1500 bp Treponema 16S rRNA gene sequences were obtained; 365 from periodontitis subjects, 250 from periodontitis-free controls. These were assigned to 110 treponeme OTUs. 93 OTUs were detected in the periodontitis subjects (mean 9.3 ± 5.2 OTUs per subject; range 9-26), and 43 OTUs were detected in controls (mean 4.3 ± 5.9 OTUs per subject; range 3-20). OTUs belonging to oral treponeme phylogroups 1-7 were detected in both subject sets. Phylogroup 1 treponemes had the highest levels of OTU richness (diversity) and clonal abundance within both subject groups. Levels of OTU richness and clonal abundance of phylogroup 2 treponemes were significantly higher in the periodontitis subjects (Mann Whitney U-test, p < 0.001). Both OTU-based and phylogeny-based analyses clearly indicated that there were significant differences in the composition of treponeme communities present in periodontitis versus control subjects. The detection frequency of five OTUs showed a statistically-significant correlation with disease status. The OTU (8P47) that corresponded to the type strain of Treponema denticola had the strongest association with periodontitis (p < 0.01).

CONCLUSIONS

Higher levels of treponeme taxon richness and clonal abundance were associated with periodontitis. However, our results clearly indicated that subjects free from clinical symptoms of periodontal disease also contained highly diverse populations of treponeme bacteria within their subgingival microbiota. Our data supports the hypothesis that specific treponeme taxa are associated with periodontal disease.

Antibody and T cell responses to Fusobacterium nucleatum and Treponema denticola in health and chronic periodontitis

The characteristics of the T cell response to the members of oral flora are poorly understood. We characterized the antibody and T cell responses to FadA and Td92, adhesins from Fusobacterium nucleatum, an oral commensal, and Treponema denticola, a periodontal pathogen, respectively. Peripheral blood and saliva were obtained from healthy individuals and patients with untreated chronic periodontitis (CP, n = 11 paris) and after successful treatment of the disease (n = 9). The levels of antigen-specific antibody were measured by ELISA. In plasma, IgG1 was the most abundant isotype of Ab for both Ags, followed by IgA and then IgG4. The levels of FadA-specific salivary IgA (sIgA) were higher than Td92-specific sIgA and the FadA-specific IgA levels observed in plasma. However, the periodontal health status of the individuals did not affect the levels of FadA- or Td92-specific antibody. Even healthy individuals contained FadA- and Td92-specific CD4⁺ T cells, as determined by the detection of intracytoplasmic CD154 after short-term in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with the antigens. Patients with CP tended to possess increased numbers of FadA- and Td92-specific CD4⁺ T cells but reduced numbers of Td92-specific Foxp3⁺CD4⁺ Tregs than the healthy subjects. Both FadA and Td92 induced the production of IFNγ and IL-10 but inhibited the secretion of IL-4 by PBMCs. In conclusion, F. nucleatum induced Th3 (sIgA)- and Th1 (IFNγ and IgG1)-dominant immune responses, whereas T. denticola induced a Th1 (IFNγ and IgG1)-dominant response. This IFNγ-dominant cytokine response was impaired in CP patients, and the Td92-induced IFNγ levels were negatively associated with periodontal destruction in patients. These findings may provide new insights into the homeostatic interaction between the immune system and oral bacteria and the pathogenesis of periodontitis.

The fate of Treponema denticola within human gingival epithelial cells

Treponema denticola is one of the major pathogens associated with chronic periodontitis. Bacterial invasion into gingival tissues is a critical process in the pathogenesis of periodontal disease. We recently reported that T. denticola can invade gingival epithelial cells. The aim of this study is to determine the fate of internalized T. denticola in gingival epithelial cells. Immortalized human gingival epithelial HOK-16B cells were infected with 5- (and 6-) carboxy-fluorescein diacetate succinimidyl ester (CFSE)-labeled live or heat-killed T. denticola for 24 h, and the presence of bacteria inside the cells was confirmed by confocal microscopy. Live T. denticola, but not heat-killed bacteria, invaded HOK-16B cells. Confocal microscopy also revealed that internalized T. denticola rarely colocalized with either endosomes or lysosomes. Transmission electron microscopy of infected cells showed that intracellular T. denticola was localized inside endosome-like structures. Although a culture-based antibiotics protection assay could not detect viable intracellular T. denticola 12 h after infection, a substantial number of bacteria were observed by confocal microscopy and weak expression of bacterial 16S ribosomal RNA was detected 48 h after infection. In addition, flow cytometric analysis of HOK-16B cells infected with CFSE-labeled T. denticola showed no loss of fluorescence over 48 h. Collectively, T. denticola invades gingival epithelial cells and remains within the host cells for many hours by resisting endolysosomal degradation. These findings may provide new insight into the role of T. denticola in the pathogenesis of periodontitis.

Subgingival microbial profiles of generalized aggressive and chronic periodontal diseases

OBJECTIVE

The aim of this study was to distinguish between generalized aggressive (GAgP) and chronic periodontitis (CP) based on the subgingival microbial profiles predominant in these diseases.

METHODS

Two-hundred and sixty subjects, 75 with GAgP and 185 with CP were recruited. Full-mouth clinical measurements were recorded. Individual subgingival plaque samples were taken from 7 sites per subject and analyzed for the prevalence and levels of 51 species by chequerboard. Differences between groups were examined by the Mann-Whitney test. Associations between bacterial species and GAgP were examined by logistic regression analysis.

RESULTS

Actinomyces gerensceriae, Actinomyces israelli, Eubacterium nodatum and Propionibacterium acnes were detected in significantly greater counts in GAgP, whereas Capnocytophaga ochracea, Fusobacterium periodonticum, Staphylococcus aureus and Veillonella parvula were more predominant in CP patients (adjusted p < 0.001). E. nodatum (at mean levels ≥4 × 10(5)) increased significantly the probability of a subject being diagnosed with GAgP than CP (OR 2.44 [0.96-6.20]), whereas P. gingivalis (OR 0.34 [0.11-0.93]) and T. denticola (OR 0.35 [0.11-0.94]) were associated with CP.

CONCLUSIONS

Very few subgingival species differed in prevalence and/or levels between GAgP and CP in this sample population. In particular, E. nodatum was strongly related to GAgP, whereas P. gingivalis and T. denticola were associated with CP.

Subgingival microbiota from Cebus apella (capuchin monkey) with different periodontal conditions

This present study evaluated the subgingival microbiota of the Cebus apella with different periodontal conditions kept by the Tufted Capuchin Monkey Procreation Center (São Paulo State University - UNESP) or free-ranging monkeys. For this purpose, clinical specimens of subgingival biofilm were collected from 52 monkeys, of both genders, 40 kept in captivity and 12 free-ranging monkeys. The primates were submitted to periodontal evaluation and biofilm samples were transferred to VMGA III transport medium and ultrapure water. The microbiota was cultivated in selective and non-selective culture media and microbial DNA was extracted and the presence of periodontal pathogens was evaluated using PCR and real-time PCR. The actinomycetes, fusobacteria, Campylobacter rectus, Eikenella corrodens, black-pigmented Gram-negative anaerobic rods, Tannerella forsythia, staphylococci and streptococci represent the predominantly detected microorganisms. Aggregatibacter actinomycetemcomitans, Dialister pneumosintes and Prevotella nigrescens were rarely observed, whereas Treponema denticola was not found. Populations of C. rectus, E. corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, T. forsythia and the total microbial load were significantly higher in animals with bone loss and, in smaller extension, in animals with gingival bleeding.

Inhibitory effect of Lactobacillus reuteri on periodontopathic and cariogenic bacteria

The interaction between Lactobacillus reuteri, a probiotic bacterium, and oral pathogenic bacteria have not been studied adequately. This study examined the effects of L. reuteri on the proliferation of periodontopathic bacteria including Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, and Tannerella forsythia, and on the formation of Streptococcus mutans biofilms. Human-derived L. reuteri strains (KCTC 3594 and KCTC 3678) and rat-derived L. reuteri KCTC 3679 were used. All strains exhibited significant inhibitory effects on the growth of periodontopathic bacteria and the formation of S. mutans biofilms. These antibacterial activities of L. reuteri were attributed to the production of organic acids, hydrogen peroxide, and a bacteriocin-like compound. Reuterin, an antimicrobial factor, was produced only by L. reuteri KCTC 3594. In addition, L. reuteri inhibited the production of methyl mercaptan by F. nucleatum and P. gingivalis. Overall, these results suggest that L. reuteri may be useful as a probiotic agent for improving oral health.