Early-onset periodontitis in Morocco is associated with the highly leukotoxic clone of Acintobacillus actinomycetemcomitans

A particular clone (JP2) of Actinobacillus actinomycetemcomitans with incre ased leukotoxin production has been isolated from individuals with early-on set periodontitis (EOP). The aim of this study was to determine the frequen cy of carriers of this clone and its association with EOP in Moroccan schoo lchildren. Of 217 plaque samples, 131 (60.4%) were culture-positive for A. actinomycetemcomitans. A total of 19 of these isolates had a 530-bp deletio n in the leukotoxin promoter region characteristic of the JP2 clone. A stro ng association between the presence of A. actinomycetemcomitans with the 53 0-bp deletion and EOP was found (adjusted OR = 29.4; 95% Cl = 8.3 - 104.4; p < 0.0005), while no association could be demonstrated between the presenc e of A. actinomycetemcomitans without the deletion and EOP (adjusted OR = 1 .3; 95% Cl = 0.5 - 2.9; p = 0.750). The study demonstrates that the endemic presence, in a human population, of the highly leukotoxic JP2 clone may re sult in an unusually high prevalence of EOP.