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

A particular clone (JP2) of Actinobacillus actinomycetemcomitans with increased leukotoxin production has been isolated from individuals with early-onset periodontitis (EOP). The aim of this study was to determine the frequency of carriers of this clone and its association with EOP in Moroccan schoolchildren. Of 217 plaque samples, 131 (60.4%) were culture-positive for A. actinomycetemcomitans. A total of 19 of these isolates had a 530-bp deletion in the leukotoxin promoter region characteristic of the JP2 clone. A strong association between the presence of A. actinomycetemcomitans with the 530-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 presence of A. actinomycetemcomitans without the deletion and EOP (adjusted OR = 1.3; 95% CI = 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 result in an unusually high prevalence of EOP.