A. actinomycetemcomitans diversity by AP-PCR and lkt promoter structure analysis

Actinobacillus actinomycetemcomitans is the major pathogen associated with aggressive periodontitis but is also found in subjects with other periodontal conditions. Objectives: to analyse the diversity of A. actinomycetemcomitans by APPCR and its relation with the strucuture of the promoter of the leukotoxin operon. Methods: Strains of A.actinomycetemcomitans isolated from Brazilian subjects with aggressive, chronic and healthy periodontal conditions (n=34), and from periodontits patients from Kenia (n=14), Japan (n=8) and Sweden (n=4)were genotyped by AP-PCR using the OPA 03 primer and the promoter strucutre of lkt determined by PCR using specific primers. A similarity matrix was obtained based on the AP-PCR bands profiles and the population structure was calculated by UPGMA metod. Results: the deletion of the lkt promoter region, characteristic of highly leukotoxic strains (JP2-like), was detected in five isolates from aggressive periodontitis Brazilian patients, but these were not clustered in the dendrogram. Conclusion: AP-PCR profiles were not able to group highly leukotoxic strains, neither there was a correlation between AP-PCR group distribution and geographic localization or host's periodontal condition.