The distribution ofTannerella forsythiain an adolescent and adult population

A comparative study on periodontitis and periodontitis-associated bacteria in Somali and non-Somali children and adolescents living in Trollhättan, Sweden

The reported prevalence of periodontitis in children and adolescents varies considerably between populations globally. This cross-sectional study compares clinical and microbiological findings on 83 Somali immigrants and 96 non-Somali children aged 10-17 years old living in Trollhättan, Sweden. The clinical examination included registration of bleeding on probing, plaque, and calculus on incisors and first molars. The distance between cemento-enamel junction and bone level was measured on bitewing radiographs. Pooled microbiological samples (1 μL) were taken from the mesial surface of 16, 11, 31, 36, and analyzed by culture and real-time polymerase chain reaction for seven periodontal associated bacterial species. The Somali participants had poorer oral hygiene and more bleeding, plaque, and calculus. Ten of the Somali but none of the non-Somali participants showed periodontal breakdown (radiographical bone loss > 3 mm), corresponding to a prevalence of 12% (95% CI: 5.9, 21.0%). The presence of A. actinomycetemcomitans was almost exclusively associated with Somali participants. Further, the JP2 clone was found in five Somalis (including two periodontitis cases) confirming the association of this clone with African populations. The Somali group showed significantly higher frequencies and numbers of Porphyromonas gingivalis and Treponema denticola, implying a mature and adult type of subgingival microbiota.

Comparison of culture and polymerase chain reaction techniques in the identification of Tannerella forsythia in periodontal health and disease, an in vitro study

Background and Objectives:

Various bacterial species from subgingival biofilm have demonstrated aetiological relevance in the initiation and progression of periodontitis. The aim of this study was to detect the presence of Tannerella forsythia (Tf) in subgingival plaque of periodontally healthy subjects and chronic periodontitis patients by using both culture and PCR technique and compare the two techniques.

Materials and Methods:

Pooled subgingival plaque samples were taken using sterile curettes from predetermined sites in 50 periodontally healthy subjects and from 50 periodontitis subjects. Samples were analyzed for the presence of T. forsythia using both techniques. Statistical analysis of the results was done using Chi-square test, sensitivity, and specificity tests.

Results:

Both techniques could detect T. forsythia in subgingival plaque samples from healthy and periodontitis subjects. Periodontally healthy individuals and individuals with chronic periodontitis using the culture technique showed the presence of T. forsythia in 14 and 34%, respectively. PCR technique showed the presence of T. forsythia in 20% healthy and 40% chronic periodontitis patients. T. forsythia detection in the periodontitis group was statistically significantly higher when compared to the healthy group by both culture and PCR technique (P = 0.019 and P = 0.029). PCR demonstrated high sensitivity and low specificity when compared to the culture technique.

Conclusion:

The results indicated that T. forsythia was more prevalent in periodontitis patients when compared with healthy subjects. The PCR was found to be more sensitive than culture technique for detection of T. forsythia from the subgingival plaque samples.

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.

Subgingival microbial consortia and the clinical features of periodontitis in adolescents

This study aimed to investigate the association between microbial consortia and the clinical features of periodontitis using a multilevel modeling approach. A total of 958 sites in 87 adolescents with periodontitis (cases) and 73 controls were microbiologically sampled and clinically examined. Associations between each of the clinical parameters clinical attachment, probing depth, supragingival plaque, calculus, bleeding on probing, and each of 18 bacterial species; and between the same clinical parameters and each of two microbial consortia identified, were investigated using mixed-effects regression modeling. Higher counts of Tannerella forsythia, Campylobacter rectus, and Porphyromonas gingivalis were all statistically significantly associated with higher values of clinical attachment level, probing depth, and bleeding on probing in the sampled site, when both case status and between-subject variance were accounted for. Higher counts for the consortium comprising the putative periodontopathogens were statistically significantly associated in a dose-response manner with both higher clinical attachment levels and with increased pocket depth. The counts for the consortium predominantly comprising the early-colonizer species were statistically significantly negatively associated with the presence of supragingival calculus, but positively associated with the presence of supragingival plaque. The study demonstrates a relationship between the counts of putative periodontopathogens and clinical attachment levels and probing pocket depths, even for low levels of these clinical parameters.

Effect of teenage smoking on the prevalence of periodontal bacteria

The aim of our study was to investigate how teenage smoking affects the prevalence of periodontal bacteria and periodontal health with the hypothesis that smoking increases the prevalence of the bacteria. Oral health of 264 adolescents (15- to 16-year-olds) was clinically examined, and their smoking history was recorded. The participants also filled in a structured questionnaire recording their general health and health habits. Pooled subgingival plaque samples were taken for polymerase chain reaction analysis of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola. The prevalence of P. intermedia (21% vs. 4%, p = 0.01) and T. forsythia and T. denticola (23% vs. 8%, p < 0.05, for both) was higher among female smokers than among non-smokers. T. forsythia and T. denticola were more often associated with bleeding on probing (29% vs. 12%; 25% vs. 10%, respectively) and deep pockets (25% vs. 15%; 23% vs. 10%, respectively) with smokers than non-smokers. Among the girls, a significant association was found between pack-years and the prevalence of P. nigrescens (p < 0.007). In both genders, A. actinomycetemcomitans and P. gingivalis were rare in this study. To conclude, periodontal bacteria were associated with higher periodontal index scores among all teenage smokers. Smoking girls harbored more frequently certain periodontal bacteria than non-smokers, but this was not seen in boys. Hence, our study hypothesis was only partly confirmed.

Polymicrobial infection with periodontal pathogens specifically enhances microRNA miR-146a in ApoE-/- mice during experimental periodontal disease

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia are periodontal pathogens associated with the etiology of adult periodontitis as polymicrobial infections. Recent studies demonstrated that oral infection with P. gingivalis induces both periodontal disease and atherosclerosis in hyperlipidemic and proatherogenic ApoE(-/-) mice. In this study, we explored the expression of microRNAs (miRNAs) in maxillas (periodontium) and spleens isolated from ApoE(-/-) mice infected with P. gingivalis, T. denticola, and T. forsythia as a polymicrobial infection. miRNA expression levels, including miRNA miR-146a, and associated mRNA expression levels of the inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) were measured in the maxillas and spleens from mice infected with periodontal pathogens and compared to those in the maxillas and spleens from sham-infected controls. Furthermore, in response to these periodontal pathogens (as mono- and polymicrobial heat-killed and live bacteria), human THP-1 monocytes demonstrated similar miRNA expression patterns, including that of miR-146a, in vitro. Strikingly, miR-146a had a negative correlation with TNF-α secretion in vitro, reducing levels of the adaptor kinases IL-1 receptor-associated kinase 1 (IRAK-1) and TNF receptor-associated factor 6 (TRAF6). Thus, our studies revealed a persistent association of miR-146a expression with these periodontal pathogens, suggesting that miR-146a may directly or indirectly modulate or alter the chronic periodontal pathology induced by these microorganisms.

Virulence of major periodontal pathogens and lack of humoral immune protection in a rat model of periodontal disease

OBJECTIVE

This study was designed to test the hypothesis that periodontal pathogens Tannerella forsythia and Porphyromonas gingivalis are synergistic in terms of virulence potential using a model of mixed-microbial infection in rats.

MATERIALS AND METHODS

Three groups of rats were infected orally with either T. forsythia or P. gingivalis in mono-bacterial infections or as mixed-microbial infections for 12 weeks and a sham-infected group were used as a control. This study examined bacterial infection, inflammation, immunity, and alveolar bone loss changes with disease progression.

RESULTS

Tannerella forsythia and P. gingivalis genomic DNA was detected in microbial samples from infected rats by PCR indicating their colonization in the rat oral cavity. Primary infection induced significantly high IgG, IgG2b, IgG1, and IgG2a antibody levels indicating activation of mixed Th1 and Th2 immune responses. Rats infected with the mixed-microbial consortium exhibited significantly increased palatal horizontal and interproximal alveolar bone loss. Histological examinations indicated significant hyperplasia of the gingival epithelium with moderate inflammatory infiltration and apical migration of junctional epithelium. The results observed differ compared to uninfected controls.

CONCLUSION

Our results indicated that T. forsythia and P. gingivalis exhibit virulence, but not virulence synergy, resulting in the immuno-inflammatory responses and lack of humoral immune protection during periodontitis in rats.

Staphylococcus aureus and Other Bacteria in Untreated Periodontitis

Whether the subgingival microbiota differ between individuals with chronic and those with aggressive periodontitis, and whether smoking influences bacterial composition, is controversial. We hypothesized that the subgingival microbiota do not differ between sites in individuals with chronic or aggressive periodontitis, or by smoking status. Bacterial counts and proportional distributions were assessed in 84 individuals with chronic periodontitis and 22 with aggressive periodontitis. No differences in probing pocket depth by periodontal status were found (mean, 0.11 mm; 95% CI, 0.6 to 0.8, p = 0.74). Including Staphylococcus aureus, Parvimonas micra, and Prevotella intermedia, 7/40 species were found at higher levels in those with aggressive periodontitis (p < 0.001). Smokers had higher counts of Tannerella forsythia (p < 0.01). The prevalence of S. aureus in non-smokers with aggressive periodontitis was 60.5%. The null hypothesis was rejected, in that P. intermedia, S. aureus, and S. mutans were robust in diagnosing sites in individuals with aggressive periodontitis. S. aureus, S. sanguinis, and T. forsythia differentiated smoking status.