Subgingival distribution of Campylobacter rectus and Tannerella forsythensis in healthy children with primary dentition

Oral Biofilm Sampling for Microbiome Analysis in Healthy Children

Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition leads to a better understanding of cariogenic and periopathogenic mechanisms. Microbial changes taking place in the oral cavity during childhood are of interest for several reasons. The evolution of the child oral microbiota and shifts in its composition need to be analyzed further to understand and possibly prevent the onset of disease. At the same time, advanced knowledge of the natural composition of oral biofilm is needed. Early stages of caries-free permanent dentition with healthy gums provide a widely unaffected subgingival habitat that can serve as an in situ baseline for studying features of oral health and disease. Analysis of children's oral biofilm during different stages in life is thus an important theme in the field. Modern molecular analysis methods can provide comprehensive information about the bacterial diversity of such biofilms. To enable microbiota data comparison, it is important to standardize each step in the procedure for molecular data generation. This procedure spans from clinical sampling, Next Generation Sequencing (NGS), bioinformatic data processing, to taxonomic interpretation. One of the most critical factors here is biofilm sampling. Sampling in children is even more challenging in particular due to limited space in subgingival areas. We thus focus on the use of paper points for subgingival sampling. This article provides a detailed protocol for oral biofilm sampling of the subgingival sulcus, the mucosa, and saliva in children.

Learned and unlearned concepts in periodontal diagnostics: a 50-year perspective

In the past 50 years, conceptual changes in the field of periodontal diagnostics have paralleled those associated with a better scientific understanding of the full spectrum of processes that affect periodontal health and disease. Fifty years ago, concepts regarding the diagnosis of periodontal diseases followed the classical pathology paradigm. It was believed that the two basic forms of destructive periodontal disease were chronic inflammatory periodontitis and 'periodontosis'- a degenerative condition. In the subsequent 25 years it was shown that periodontosis was an infection. By 1987, major new concepts regarding the diagnosis and pathogenesis of periodontitis included: (i) all cases of untreated gingivitis do not inevitably progress to periodontitis; (ii) progression of untreated periodontitis is often episodic; (iii) some sites with untreated periodontitis do not progress; (iv) a rather small population of specific bacteria ('periodontal pathogens') appear to be the main etiologic agents of chronic inflammatory periodontitis; and (v) tissue damage in periodontitis is primarily caused by inflammatory and immunologic host responses to infecting agents. The concepts that were in place by 1987 are still largely intact in 2012. However, in the decades to come, it is likely that new information on the human microbiome will change our current concepts concerning the prevention, diagnosis and treatment of periodontal diseases.

Acquisition of oral microbes and associated systemic responses of newborn nonhuman primates

The acquisition and development of the complex oral microbiome remain ill defined. While selected species of oral bacteria have been examined in relation to their initial colonization in neonates, a more detailed understanding of the dynamics of the microbiome has been developed only in adults. The current investigation used a nonhuman primate model to document the kinetics of colonization of the oral cavities of newborns and infants by a range of oral commensals and pathogens. Differences in colonization were evaluated in newborns from mothers who were maintained on an oral hygiene regimen pre- and postparturition with those displaying naturally acquired gingivitis/periodontitis. The results demonstrate distinct profiles of acquisition of selected oral bacteria, with the transmission of targeted pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, being passed on primarily from mothers with gingivitis/periodontitis. This colonization resulted in defined patterns of systemic antibody responses in the infants. The significant relative risk measures for infection with the pathogens, as well as the relationship of oral infection and blood serum antibody levels, were consistent with those of the newborns from mothers with gingivitis/periodontitis. These findings indicate that the early acquisition of potentially pathogenic oral bacterial species might impact the development of mucosal responses in the gingiva and may provide an enhanced risk for the development of periodontitis later in life.

Microbiota-targeted therapies: an ecological perspective

The connection between disease and the disruption of homeostatic interactions between the host and its microbiota is now well established. Drug developers and clinicians are starting to rely more heavily on therapies that directly target the microbiota and on the ecology of the microbiota to understand the outcomes of these treatments. The effects of those microbiota-targeted therapies that alter community composition range in scale from eliminating individual strains of a single species (for example, with antibacterial conjugate vaccines) to replacing the entire community with a new intact microbiota (for example, by fecal transplantation). Secondary infections linked to antibiotic use provide a cautionary tale of the unintended consequences of perturbing a microbial species network and highlight the need for new narrow-spectrum antibiotics with rapid companion diagnostics. Insights into microbial ecology will also benefit the development of probiotics, whose therapeutic prospects will depend on rigorous clinical testing. Future probiotics may take the form of a consortium of long-term community residents: "a fecal transplant in a capsule." The efficacy of microbiota-targeted therapies will need to be assessed using new diagnostic tools that measure community function rather than composition, including the temporal response of a microbial community to a defined perturbation such as an antibiotic or probiotic.

Microbiota associated with infections of the jaws

The microbial infections involving the craniofacial skeleton, particularly maxilla and mandible, have direct relationship with the dental biofilm, with predominance of obligate anaerobes. In some patients, these infections may spread to bone marrow or facial soft tissues, producing severe and life-threatening septic conditions. In such cases, local treatment associated with systemic antimicrobials should be used in order to eradicate the sources of contamination. This paper discuss the possibility of spread of these infections and their clinical implications for dentistry, as well as their etiology and aspects related to microbial virulence and pathogenesis.

Distribution of periodontopathic bacterial species in Japanese children with developmental disabilities

Background

Recent developments in molecular biological techniques have enabled rapid detection of periodontopathic bacterial species in clinical specimens. Accumulated evidence suggests that detection of specific bacterial species enables identification of subjects at high risk for the onset of periodontitis. We investigated the distribution of 10 selected periodontopathic bacterial species in dental plaque specimens obtained from children with disabilities who were attending daycare centers.

Methods

A total of 187 children (136 boys, 51 girls) aged 1-6 years old and diagnosed with such disabilities as mental retardation, cerebral palsy, and autism, participated in the study. Subgingival dental plaque specimens were collected from the buccal side of the maxillary left second primary molar after a clinical examination. Bacterial DNA was extracted from the specimens and PCR analyses were carried out to detect 10 selected periodontopathic species using specific primers for each. In addition, statistical analyses were performed to analyze the correlations among clinical parameters and the detected species.

Results

The most frequently detected species was Capnocytophaga sputigena (28.3%), followed by Aggregatibacter actinomycetemcomitans (20.9%) and Campylobacter rectus (18.2%). Eikenella corrodens, Capnocytophaga ochracea, and Prevotella nigrescence were detected in approximately 10% of the specimens, whereas Treponema denticola, Tannerella forsythia, and Prevotella intermedia were rarely found, and Porphyromonas gingivalis was not detected in any of the subjects. The total numbers of detected species were positively correlated with the age of the subjects. There were 10 subjects with positive reactions for T. denticola and/or T. forsythia, in whom the total number of bacterial species was significantly higher as compared to the other subjects. Furthermore, subjects possessing C. rectus showed significantly greater values for periodontal pocket depth, gingival index, and total number of species.

Conclusion

We found that approximately one-fourth of the present subjects with disabilities who possessed at least one of T. denticola, T. forsythia, and C. rectus were at possible risk for periodontitis. Follow-up examinations as well as preventive approaches should be utilized for such individuals.

Effects of age and oral disease on systemic inflammatory and immune parameters in nonhuman primates

This report evaluated systemic inflammatory and immune biomarkers in a cohort of Macaca mulatta (rhesus monkeys) maintained as a large family social unit, including an age range from <1 year to >24 years. We hypothesized that the systemic host responses would be affected by the age, gender, and clinical oral presentation of the population, each contributing to inflammatory and immune responses that would reflect chronic oral infections. The results demonstrated that the prevalence and severity of periodontitis, including missing teeth, increased significantly with age. Generally, minimal differences in clinical parameters were noted between the genders. Systemic inflammatory mediators, including acute-phase reactants, prostaglandin E(2) (PGE(2)), cytokines/chemokines, and selected matrix metalloproteinases (MMP), demonstrated significant differences among the various age groups of animals. Levels of many of these were increased with age, although PGE(2), RANTES, bactericidal permeability-inducing factor (BPI), MMP-1, and MMP-9 levels were significantly increased in the young group ( approximately 1 to 3 years old) relative to those for the older animals. We observed that in the adult and aged animals, levels of the systemic inflammatory mediators related to gingival inflammation and periodontal tissue destruction were significantly elevated. Serum antibody levels in response to a battery of periodontal pathogens were generally lower in the young animals, <50% of those in the adults, and were significantly related to aging in the cohort. The levels of antibodies, particularly those to Porphorymonas gingivalis, Fusobacterium nucleatum, and Tannerella forsythia, were most significantly elevated in animals with periodontal disease, irrespective of the age of the animal. These results provide a broad description of oral health and host responses in a large cohort of nonhuman primates from very young animals to the aged of this species. The findings afford a base of data with which to examine the ontogeny of host responses at mucosal sites, such as the gingival tissues.

Colonization pattern of periodontal bacteria in Japanese children and their mothers

BACKGROUND AND OBJECTIVE

The purpose of this study was to determine the time of infection by anaerobic gram-negative rods associated with periodontal disease, and to clarify their transmission from mother to child.

MATERIAL AND METHODS

Seventy-eight Japanese children (including 10 siblings), aged from 3 to 9 years, and 68 mothers, were enrolled in this study. Colonization by 11 periodontal bacterial species was determined using polymerase chain reaction amplification of samples of subgingival plaque obtained from the children and their mothers.

RESULTS

The detection rates of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola increased in children after the age of 6 years. We found a high consistency in colonization by P. gingivalis, T. denticola, Prevotella intermedia and Prevotella nigrescens in 9 of the 10 siblings. The average number of bacterial species in plaque samples harboring Fusobacterium nucleatum and/or Fusobacterium periodonticum was significantly greater than in those without, in both children and mothers. Kappa statistical analysis revealed that the detection of Capnocytophaga gingivalis, Capnocytophaga ochracea, Campylobacter rectus and T. denticola in children was consistent with that in the mother.

CONCLUSION

Periodontal bacterial colonization in Japanese children increased with age and was associated with F. nucleatum and/or periodonticum, and the bacterial flora in children was similar to that in their mothers.