title: A 5-year longitudinal study of Tannerella forsythia prtH genotype: association with loss of attachment.
abstract: BACKGROUND
  Tannerella forsythia (previously T. forsythensis) in subgingival plaque has been recognized as a defined periodontal pathogen, but its mere presence may be insufficient for disease initiation and/or progression. The organism may produce a cysteine protease, encoded by the prtH gene, which may play a role in the transition from commensal organism to opportunistic pathogen. This study aimed to relate changes in the level of T. forsythia prtH genotype over a 5-year period to a concomitant loss of attachment.
  
  
  METHODS
  Real-time polymerase chain reaction was used to quantify the level of the prtH gene in plaque samples from subjects with and without attachment loss (> or =2 mm in at least two sites) over a 5-year period. Clinical measures and subgingival plaque samples were obtained at yearly intervals.
  
  
  RESULTS
  Baseline levels of the prtH genotype were significantly lower in the subjects without loss of attachment compared to those who lost attachment over 1, 2, 4, or 5 years. In the subjects with loss of attachment, the higher prtH levels at baseline were not maintained until the end of the observation period.
  
  
  CONCLUSIONS
  Higher levels of the prtH genotype were associated significantly with future attachment loss.
authors.affiliation: School of Dentistry, University of Queensland, Brisbane, QLD, Australia. s.hamlet@griffith.edu.au
authors.forename: S M
authors.initials: SM
authors.lastname: Hamlet
authors.forename: N
authors.initials: N
authors.lastname: Ganashan
authors.forename: M P
authors.initials: MP
authors.lastname: Cullinan
authors.forename: B
authors.initials: B
authors.lastname: Westerman
authors.forename: J E
authors.initials: JE
authors.lastname: Palmer
authors.forename: G J
authors.initials: GJ
authors.lastname: Seymour
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001439:Bacteroides / Q000235:genetics* / Q000472:pathogenicity; D003546:Cysteine Endopeptidases / Q000235:genetics*; D003773:Dental Plaque / Q000382:microbiology; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000382:microbiology*; D010514:Periodontal Pocket / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003546:Cysteine Endopeptidases; C089744:PrtH protein, bacteria