title: Attachment loss in Moroccan early onset periodontitis patients and infection with the JP2-type of Actinobacillus actinomycetemcomitans.
abstract: BACKGROUND
  A clone of Actinobacillus actinomycetemcomitans (JP2) with increased leukotoxin production and characterized by a 530-bp deletion in the leukotoxin gene operon is endemically present in Morocco and strongly associated with the presence of early onset periodontitis (EOP).
  
  
  OBJECTIVE
  To compare patterns of attachment loss among EOP-patients with or without JP2-type of A. actinomycetemcomitans in dental plaque.
  
  
  METHODS
  Among 45 Moroccan adolescents with EOP (i.e. one or more teeth with attachment loss >/= 3 mm) 39 had cultivable plaque samples. Fifteen (38.5%) were culture-positive for A. actinomycetemcomitans of the JP2-type as determined by PCR, and 24 (61.5%) were not (mean age 16.5 years in both groups).
  
  
  RESULTS
  EOP-patients culture-positive for A. actinomycetemcomitans of the JP2-type had significantly more teeth with attachment loss (mean 5.1, median 4.0) than EOP-patients not culture-positive for A. actinomycetemcomitans of the JP2-type (mean 2.8 teeth, median 1.0) (p = 0.02), and higher attachment loss (mean 4.3 mm vs. 3.4 mm; median 4.0 mm vs. 3.0 mm) (p = 0.01). No major differences could be detected between the two groups in the pattern of affected teeth in the dentition.
  
  
  CONCLUSIONS
  The study demonstrates increased periodontal destruction among EOP-patients culture-positive for A. actinomycetemcomitans of the JP2-type compared with EOP-patients without the JP2-clone.
mesh_terms: D000189:Actinobacillus Infections / Q000382:microbiology*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification* / Q000502:physiology; D010520:Aggressive Periodontitis / Q000382:microbiology*; D001427:Bacterial Toxins / Q000235:genetics; D020029:Base Pairing / Q000235:genetics; D002999:Clone Cells; D003430:Cross-Sectional Studies; D003773:Dental Plaque / Q000382:microbiology; D005098:Exotoxins / Q000235:genetics; D017353:Gene Deletion; D006801:Humans; D009018:Morocco; D017622:Periodontal Attachment Loss / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; C018579:leukotoxin