title: Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic periodontitis.
abstract: OBJECTIVE
  The aim of this study was to investigate subgingival infection frequencies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans strains with genetic variation in Chinese chronic periodontitis (CP) patients and to evaluate its correlation with clinical parameters.
  
  
  METHODS
  Two multiplex polymerase chain reaction (PCR) assays were developed to detect the 16SrDNA, collagenase (prtC) and fimbria (fimA) genes of P. gingivalis and the 16SrDNA, leukotoxin (lktA) and fimbria-associated protein (fap) genes of A. actinomycetemcomitans in 60 sulcus samples from 30 periodontal healthy subjects and in 122 subgingival plaque samples from 61 patients with CP. The PCR products were further T-A cloned and sent for nucleotide sequence analysis.
  
  
  RESULTS
  The 16SrDNA, prtC and fimA genes of P. gingivalis were detected in 92.6%, 85.2% and 80.3% of the subgingival plaque samples respectively, while the 16SrDNA, lktA and fap genes of A. actinomycetemcomitans were in 84.4%, 75.4% and 50.0% respectively. Nucleotide sequence analysis showed 98.62%~100% homology of the PCR products in these genes with the reported sequences. P. gingivalis strains with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ were predominant in deep pockets (>6 mm) or in sites with attachment loss > or =5 mm than in shallow pockets (3~4 mm) or in sites with attachment loss < or =2 mm (P<0.05). P. gingivalis strains with prtC+/fimA+ also showed higher frequency in gingival index (GI)=3 than in GI=1 group (P<0.05).
  
  
  CONCLUSIONS
  Infection of P. gingivalis with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ correlates with periodontal destruction of CP in Chinese. Nonetheless P. gingivalis fimA, prtC genes and A. actinomycetemcomitans lktA gene are closely associated with periodontal destruction, while A. actinomycetemcomitans fap gene is not.
authors.affiliation: Department of Stomatology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yan-min
authors.initials: YM
authors.lastname: Wu
authors.forename: Jie
authors.initials: J
authors.lastname: Yan
authors.forename: Li-li
authors.initials: LL
authors.lastname: Chen
authors.forename: Zhi-yuan
authors.initials: ZY
authors.lastname: Gu
mesh_terms: D000189:Actinobacillus Infections / Q000453:epidemiology / Q000382:microbiology*; D000328:Adult; D000368:Aged; D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016866:Bacteroidaceae Infections / Q000453:epidemiology / Q000382:microbiology*; D002681:China / Q000453:epidemiology; D002908:Chronic Disease; D003773:Dental Plaque / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D005891:Gingivitis / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000453:epidemiology / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013045:Species Specificity; D013223:Statistics as Topic