Background

Aggregatibacter actinomycetemcomitans produces a leukotoxin that activates a pro-inflammatory death of human monocytes/macrophages. A specific clone of this bacterium (JP2) has a 530-base pair deletion in the leukotoxin promoter gene and significantly enhanced expression of leukotoxin. This specific clone of A. actinomycetemcomitans is common in some African populations and has a strong association with periodontal attachment loss in adolescents in these populations. Chewing sticks of plant origin are commonly used as oral hygiene tool in Africa, but their role as a therapeutic agent in periodontal disease is poorly investigated.

Results

Ethanol extracts were made from 7 common plants used as chewing sticks in West-Africa. None of the tested extracts inhibited growth of A. actinomycetemcomitans. However, extracts from Psidium guajava (Guava) completely neutralized the cell death and pro-inflammatory response of human leukocytes induced by the leukotoxin. None of the six other tested chewing stick extracts showed this effect.

Conclusions

The discovery that extracts from Guava efficiently neutralizes A. actinomycetemcomitans leukotoxicity might lead to novel therapeutic agents and strategies for prevention and treatment of aggressive forms of periodontitis induced by infections with the highly leukotoxic JP2 clone of this bacterium.

Background

The Child Perceptions Questionnaire (CPQ) is a self-reported questionnaire developed to measure oral health-related quality of life in children. The CPQ aims to improve the description of children's oral health, while taking into consideration the importance of psychological aspects in the concept of health. The CPQ exists in two versions: the CPQ8–10 for children aged 8–10 years and the CPQ11–14 for those aged 11–14 years. The aim of this study was to develop a Danish version of the CPQ8–10 and the CPQ11–14 and to evaluate its validity for use among Danish-speaking children.

Methods

The instruments were translated from English into Danish in accordance with a recommended translation procedure. Afterwards, they were tested among children aged 8–10 (n = 120) and 11–14 years (n = 225). The validity was expressed by the correlation between overall CPQ scores and i) self-reported assessment of the influence of oral conditions on everyday life (not at all, very little, some, a lot, very much) and ii) the self-reported rating of oral health. Furthermore, groups of children with assumed decreased oral health-related quality of life were compared with children with healthy oral conditions. Finally, we examined the internal consistency.

Results

The correlation between overall CPQ scores and global assessments of the influence of oral conditions on everyday life showed Spearman correlation coefficients of 0.45, P < 0.001 for CPQ8–10 and 0.50, P < 0.001 for CPQ11–14. The correlation between overall CPQ scores and the self-reported rating of oral health showed Spearman correlation coefficients of 0.45, P < 0.001 for CPQ8–10 and 0.17, P = 0.010 for CPQ11–14.

The median overall CPQ8–10 scores were 7 for individuals with healthy oral conditions, 5 for individuals with cleft lip and palate, and 15 for individuals with rare oral diseases. The median overall CPQ11–14 scores were 9 for individuals with healthy oral conditions, 9 for individuals with cleft lip and palate, 17.0 for individuals with rare oral diseases, and 22.0 for individuals with fixed orthodontic appliances. There were statistically significant differences between the groups of children with healthy oral conditions and each of the subgroups, except for children with cleft lip and palate.

Chronbach'α were 0.82 for CPQ8–10 and 0.87 for CPQ11–14.

Conclusion

The results of this study reveal that the Danish CPQ8–10 and CPQ11–14, seem to be valid instruments for measuring oral health-related quality of life in children although its ability to discriminate between children with cleft lip and palate and healthy children seem to be limited.

We developed a loop-mediated isothermal amplification method that detects the JP2 clone of Aggregatibacter actinomycetemcomitans, which induces aggressive periodontitis in adolescents of North and West African descents. Being independent of special equipment, this specific and sensitive method offers significant advantages for screening of patients on a population basis and in clinical settings.

The natural history, microevolution, and patterns of interindividual transmission and global dissemination of the JP2 clone of Aggregatibacter (Actinobacillus) actinomycetemcomitans were studied by population genetic analysis. The JP2 clone is strongly associated with aggressive periodontitis in adolescents of African descent and differs from other clones of the species by several genetic peculiarities, including a 530-bp deletion in the promoter region of the leukotoxin gene operon, which results in increased leukotoxic activity. Multilocus sequence analysis of 82 A. actinomycetemcomitans strains, 66 of which were JP2 clone strains collected over a period of more than 20 years, confirmed that there is a clonal population structure with evolutionary lineages corresponding to serotypes. Although genetically highly conserved, as shown by alignment of sequences of eight housekeeping genes, strains belonging to the JP2 clone had a number of point mutations, particularly in the pseudogenes hbpA and tbpA. Characteristic mutations allowed isolates from individuals from the Mediterranean area and from West Africa, including the Cape Verde Islands, to be distinguished. The patterns of mutations indicate that the JP2 clone initially emerged as a distinct genotype in the Mediterranean part of Africa approximately 2,400 years ago and subsequently spread to West Africa, from which it was transferred to the American continents during the transatlantic slave trade. The sustained exclusive colonization of individuals of African descent despite geographical separation for centuries suggests that the JP2 clone has a distinct host tropism. The colonization of family members by JP2 clone strains with unique point mutations provides strong evidence that there is intrafamilial transmission and suggests that dissemination of the JP2 clone is restricted to close contacts.

The JP2 clone of Actinobacillus actinomycetemcomitans is associated with early-onset periodontitis in certain ethnic populations of African origin. Here, we describe and evaluate a set of primers for PCR to assay for the presence of A. actinomycetemcomitans and to discriminate between JP2-like strains and other genotypes in subgingival plaque samples.