leukotoxin and Gingivitis

The influence of Aggregatibacter actinomycetemcomitans on inflammation in subjects with gingivitis has not been studied in great detail. Seventeen healthy young adults with plaque-induced gingivitis or localized mild chronic periodontitis harboring cultivable numbers of A. actinomycetemcomitans were thoroughly examined. Samples of subgingival plaque were obtained from mesial surfaces of all teeth present. In addition, 12 oral mucosal surfaces and unstimulated saliva were sampled. Species identity, presence of the leukotoxin gene, and absence of a specific 530 b deletion in the leukotoxin promoter region indicating non-JP2-like strains were assessed by polymerase chain reaction. Based on a multilevel random intercept model adjusted for probing depth, age, and smoking status, the odds of bleeding on probing was increased by a factor of 1.89 (1.09-3.29, p = 0.024) if, in addition to plaque, A. actinomycetemcomitans could be recovered from the site. At a site without visible supragingival plaque but with cultivable numbers of subgingival A. actinomycetemcomitans the odds ratio of bleeding on probing was 3.37 (0.86-13.2, p = 0.081). Simulating variance partition coefficients revealed that between 1-2% (a clean, shallow site without A. actinomycetemcomitans; a deep site covered by plaque containing A. actinomycetemcomitans) and 6-7% (a moderately deep site with neither visible plaque nor cultivable A. actinomycetemcomitans) of the residual variance was attributable to differences between subjects. The present cross-sectional study indicates that non-JP2-like strains of A. actinomycetemcomitans may enhance gingival bleeding tendency even in the absence of clinically visible supragingival plaque.

Topics: Adult; Aggregatibacter actinomycetemcomitans; Colony Count, Microbial; Cross-Sectional Studies; Dental Plaque; Exotoxins; Female; Gingivitis; Humans; Male; Multilevel Analysis; Periodontal Index; Promoter Regions, Genetic; Sequence Deletion; Species Specificity; Young Adult

The JP2 clone of Actinobacillus actinomycetemcomitans, a high-leukotoxin-producing strain, characterized by a 530-basepair (bp) deletion in the promoter region of the leukotoxin gene operon and mainly found among individuals with African origin, is associated with localized aggressive periodontitis. The objective of the study was to examine the occurrence of periodontal disease in a Moroccan immigrant family living in Denmark in which the oldest son (14 year) was referred and treated for localized aggressive periodontitis. Further, the potential occurrence of the JP2 clone of A. actinomycetemcomitans in the family was examined. Here we present the clinical, radiographic, and microbiological findings from the family. Clinical and radiographic examination of the other family members revealed that 3 of 5 younger siblings had localized aggressive periodontitis, one had gingivitis and the mother had chronic periodontitis. Despite scaling followed by intensive maintenance therapy several family members, including the sibling with gingivitis, had further attachment loss at the 1-year examination. The JP2 clone of A. actinomycetemcomitans was isolated from subgingival plaque samples from 4 children with periodontitis. In contrast, it was not detected in plaque from the oldest boy, who had been treated for localized aggressive periodontitis by surgery combined with antibiotic therapy. The 4 children with periodontitis and colonized with the JP2 clone were treated by scaling and antibiotic administration. One month later the JP2 clone could still be detected in plaque samples. In conclusion, it is confirmed that members of immigrant families with African origin are potential carriers of the JP2 clone and that those families often have multiple family members with localized aggressive periodontitis. It is proposed that those families are given periodontal examination frequently to benefit from early diagnosis and treatment of the disease.

Topics: Actinobacillus Infections; Adolescent; Adult; Aggregatibacter actinomycetemcomitans; Bacterial Toxins; Base Sequence; Child; Chronic Disease; Denmark; Dental Plaque; Emigration and Immigration; Exotoxins; Female; Follow-Up Studies; Gingivitis; Humans; Male; Morocco; Operon; Periodontitis; Promoter Regions, Genetic; Sequence Deletion

Actinobacillus actinomycetemcomitans is a major periodontal pathogen which is associated with both early-onset periodontitis and adult cases refractory to conventional periodontal therapy, although the organism has also been shown to be widely distributed among dentate healthy individuals. The observed disease status may be associated with a variation in virulence of different strains or clones. The aim of the present study was to analyse genotype distribution as assessed by an arbitrarily primed polymerase chain reaction (AP-PCR) among 51 isolates of A. actinomycetemcomitans recovered from more than 200 young adult recruits with no or minor periodontal disease. In addition, isolates from 25 periodontitis patients as well as reference strains were genotyped. Primers amplifying (i) a specific sequence in the ltxA region, (ii) a specific 16S rRNA sequence and (iii) sequences in the leukotoxin promoter region were used to verify species identity of the strains. Three random oligonucleotide primers were employed to analyse genomic polymorphisms of the organism by means of PCR. A total of 19 genotypes could be distinguished, which were grouped by cluster analysis into 5 major clusters based on genetic similarity and a complete linkage sort. Whereas 3 clusters assembled A. actinomycetemcomitans genotypes isolated from both healthy subjects and periodontitis patients, one cluster containing 4 different genotypes exclusively comprised isolates from healthy or gingivitis subjects. Another cluster with 2 genotypes consisted of strains originating from periodontitis patients (p < 0.05). One strain characterized by a specific 530 bp deletion in the promoter region of the leukotoxin region was identified in a Ghanese patient with localized juvenile periodontitis. It was concluded that there is considerable clonal diversity of A. actinomycetemcomitans strains isolated from healthy or periodontally diseased subjects, and that genetically closely related groups might be associated with health or disease.

Topics: Actinobacillus Infections; Adolescent; Adult; Aggregatibacter actinomycetemcomitans; Aggressive Periodontitis; Bacterial Toxins; Base Pairing; Clone Cells; Cytotoxins; Exotoxins; Gene Deletion; Genetic Linkage; Genotype; Gingivitis; Humans; Male; Periodontitis; Periodontium; Polymerase Chain Reaction; Polymorphism, Genetic; Promoter Regions, Genetic; RNA, Ribosomal, 16S; Virulence