title: Tannerella forsythensis prtH genotype and association with periodontal status.
abstract: BACKGROUND
  The prtH gene of Tannerella forsythensis encodes for a cysteine protease possessing virulent properties. Subgingival colonization by T. forsythensis with this genotype has been suggested to be a discriminator between periodontal health and disease. This study examined the prevalence of T. forsythensis prtH genotype in subgingival plaque and its association with periodontal disease progression and current disease status.
  
  
  METHODS
  Subjects harboring T. forsythensis in their subgingival plaque were identified using real-time polymerase chain reaction (PCR). The presence or absence of the prtH genotype was assessed by conventional PCR. Probing depths and relative attachment levels were also assessed.
  
  
  RESULTS
  The prtH genotype was detected in 13 of 56 (23.2%) subjects harboring T. forsythensis in their subgingival plaque. Periodontal disease progression was defined as two or more sites with > or = 2 mm attachment loss in the previous 2-year period; current disease was defined as four or more sites with probing depths > or = 4 mm. The odds of periodontal disease (progression and/or current disease) were 1.55 times greater in subjects harboring prtH genotype T. forsythensis than in subjects in whom prtH was not detected. The prtH genotype was associated with higher numbers of T. forsythensis. In subjects with high levels of T. forsythensis, prtH genotype was associated with an increased extent of periodontal disease 2 years subsequently.
  
  
  CONCLUSIONS
  These results show that T. forsythensis prtH genotype is associated with high levels of T. forsythensis. However, further work is needed to determine whether it also is a useful marker of periodontal disease progression in T. forsythensis-infected subjects.
authors.affiliation: School of Dentistry, The University of Queensland, Brisbane, QLD, Australia. s.hamlet@uq.edu.au
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Hamlet
authors.forename: Tara B
authors.initials: TB
authors.lastname: Taiyeb-Ali
authors.forename: Mary P
authors.initials: MP
authors.lastname: Cullinan
authors.forename: Bill
authors.initials: B
authors.lastname: Westerman
authors.forename: Janet E
authors.initials: JE
authors.lastname: Palmer
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Seymour
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001439:Bacteroides / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity; D016022:Case-Control Studies; D003546:Cysteine Endopeptidases / Q000235:genetics*; D003773:Dental Plaque / Q000382:microbiology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010510:Periodontal Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D037521:Virulence Factors
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D003546:Cysteine Endopeptidases; C089744:PrtH protein, bacteria