The JP2 genotype of Aggregatibacter actinomycetemcomitans and marginal periodontitis in the mixed dentition

Periodontal diseases in Thai schoolchildren. Clinical and microbiological observations

The prevalence of periodontitis among Thai schoolchildren is unknown. In a cross-sectional study, the prevalence and severity of periodontal diseases, in a group of Thai schoolchildren, along with the presence and numbers of bacterial species commonly associated with periodontitis were investigated. A consent form was sent out to 192 schoolchildren in one school (Chanachanupathom School) in Chana, Southern Thailand (in the age range of 12-18 years) and 119 attended for a clinical and microbiological examination. Clinical recordings included number of teeth present, DMFT, plaque index, bleeding index, clinical attachment loss (CAL), and probing pocket depth (PPD). Pooled plaque samples were analyzed with culture and qPCR against bacteria associated with periodontitis. The children had low caries experience (DMFT = 3.2 ± 2.3), poor oral hygiene, high bleeding scores, and 67 (56.3%) had at least one interproximal site with CAL ≥ 1 mm. Thirty-seven (31.1%) of the children were diagnosed with periodontitis stage I, and sixteen (13.4%) were classified as periodontitis Stage II. Aggregatibacter actinomycetemcomitans was sparsely found in all but the healthy clinical groups (gingivitis, periodontitis Stage I and II), while the groups showed a high prevalence of Fusobacterium spp., Prevotella intermedia/nigrescens, and Campylobacter species as well as of the periodontitis-associated species Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Thai schoolchildren have poor oral hygiene with abundant amounts of plaque and high presence of bleeding. Early onset periodontitis is common but mostly in its mild form and is not associated with the presence of A. actinomycetemcomitans.

Prevalence of Aggregatibacter actinomycetemcomitans and Periodontal Findings among 14 to 15-Year Old Danish Adolescents: A Descriptive Cross-Sectional Study

Aggregatibacter actinomycetemcomitans (Aa) is a keystone pathogen associated with periodontitis in adolescents. The knowledge on the prevalence of Aa and periodontitis among adolescents in Northern Europe is sparse. A total of 525 14- to 15-year-old adolescents from the municipality of Aarhus, Denmark, underwent a full-mouth clinical examination. Plaque score (PS), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment loss (CAL) were recorded. Subgingival plaque samples (SPS) and stimulated saliva samples (SSS) were collected and analyzed for the presence of JP2 and non-JP2 genotypes of Aa using real-time PCR. A total of 70 (13.3%) individuals were positive for Aa, with 17 found in SPS, 19 in SSS, and 35 in both. The highly leukotoxic JP2 genotype of Aa was not detected. The individuals positive for Aa in both SPS and SSS had poorer periodontal outcomes (PPD and CAL) than individuals without Aa and individuals carrying Aa in either SPS or SSS only. In conclusion, 13% of 14- to 15-year-old Danish adolescents were positive for Aa, and the presence of Aa in both SPS and SSS was associated with poorer periodontal outcomes.

Grade C molar-incisor pattern periodontitis subgingival microbial profile before and after treatment

Aim: This study evaluated the influence of periodontal therapy on the microbiological profile of individuals with Grade C Molar-Incisor Pattern Periodontitis (C/MIP).

Methods: Fifty-three African-American participants between the ages of 5–25, diagnosed with C/MIP were included. Patients underwent full mouth mechanical debridement with systemic antibiotics (metronidazole 250 mg + amoxicillin 500 mg, tid, 7 days). Subgingival samples were collected from a diseased and a healthy site from each individual prior to treatment and at 3, 6, 12, 18 and 24 months after therapy from the same sites. Samples were subjected to a 16S rRNA gene based-microarray.

Results: Treatment was effective in reducing the main clinical parameters of disease. Aggregatibacter actinomycetemcomitans (A.a.) was the strongest species associated with diseased sites. Other species associated with diseased sites were Treponema lecithinolyticum and Tannerella forsythia. Species associated with healthy sites were Rothia dentocariosa/mucilaginosa, Eubacterium yurii, Parvimonas micra, Veillonella spp., Selenomonas spp., and Streptococcus spp. Overall, treatment was effective in strongly reducing A.a. and other key pathogens, as well as increasing health-associated species. These changes were maintained for at least 6 months.

Conclusions:Treatment reduced putative disease-associated species, particularly A.a., and shifted the microbial profile to more closely resemble a healthy-site profile. (Clinicaltrials.gov registration #NCT01330719).

High salivary levels of JP2 genotype of Aggregatibacter actinomycetemcomitans is associated with clinical attachment loss in Moroccan adolescents

It has previously been shown that the presence of Aggregatibacter actinomycetemcomitans in subgingival plaque is significantly associated with increased risk for clinical attachment loss. The highly leukotoxic JP2 genotype of this bacterium is frequently detected in adolescents with aggressive forms of periodontitis. The aims of the study were to quantify the levels of JP2 and non-JP2 genotypes of A. actinomycetemcomitans in saliva of Moroccan adolescents with the JP2 genotype earlier detected in the subgingival plaque. The salivary concentrations of inflammatory proteins were quantified and linked to the clinical parameters and microbial findings. Finally, a mouth rinse with leukotoxin-neutralizing effect was administrated and its effect on the levels the biomarkers and A. actinomycetemcomitans examined. The study population consisted of 22 adolescents that previously were found to be positive for the JP2 genotype in subgingival plaque. Periodontal registration and sampling of stimulated saliva was performed at baseline. A mouth rinse (active/placebo) was administrated, and saliva sampling repeated after 2 and 4 weeks rinse. The salivary levels of JP2 and non-JP2 were analyzed by quantitative PCR and inflammatory proteins by ELISA. Both the JP2 and the non-JP2 genotype were detected in all individuals with significantly higher levels of the non-JP2. Enhanced levels of the JP2 genotype of A. actinomycetemcomitans was significantly correlated to the presence of attachment loss (≥3 mm). Salivary concentrations of inflammatory biomarkers did not correlate to periodontal condition or levels of A. actinomycetemcomitans. The use of active or placebo leukotoxin-neutralizing mouth rinse did not significantly interfered with the levels of these biomarkers. Saliva is an excellent source for detection of A. actinomycetemcomitans on individual basis, and high levels of the JP2 genotype were significantly associated with the presence of clinical attachment loss.

Aggregatibacter (Actinobacillus) actimycetemcomitans leukotoxin and human periodontitis - A historic review with emphasis on JP2

Aggregatibacter (Actinobacillus) actimycetemcomitans (Aa) is a gram-negative bacterium that colonizes the human oral cavity and is causative agent for localized aggressive (juvenile) periodontitis (AgP). In the middle of 1990s, a specific JP2 clone of belonging to the cluster of serotype b strains of Aa with highly leukotoxicity (leukotoxin, LtxA) able to kill human immune cells was isolated. JP2 clone of Aa was strongly associated with in particularly in rapidly progressing forms of aggressive periodontitis. The JP2 clone of Aa is transmitted through close contacts. Therefore, AgP patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontitis lesions are relatively high. Furthermore, timely periodontal treatment, including periodontal surgery supplemented by the use of antibiotics, is warranted. More importantly, periodontal attachment loss should be prevented by early detection of the JP2 clone of Aa by microbial diagnosis testing and/or preventive means.