OBJECTIVETo detect the distribution of fimA genotype of P. gingivalis in periodontally healthy adults and chronic periodontitis patients, and to investigate the relationship between the prevalence of fimA genotype of P. gingivalis and periodontal health status.

METHODSSubgingival plaque samples were collected from 136 periodontally healthy adults and 115 chronic periodontitis patients. The occurrence of P. gingivalis was determined by P. gingivalis 16S rRNA PCR. Distribution of fimA genotype was assessed in P. gingivalis positive samples by PCR using primers pairs homologous to the different fimA genes.

RESULTSP. gingivalis was detected in 22.1% of the healthy subjects and 81.7% of chronic periodontitis patients. A single fimA genotype was detected in most subgingival plaque samples. In P. gingivalis-positive healthy adults, the most prevalent fimA genotype of P. gingivalis was type I fimA. In contrast, a majority of chronic periodontitis patients carried type II fimA, followed by IV fimA and I b fimA. The univariate analysis illustrated that chronic periodontitis was associated with occurrences of type I fimA (OR = 0.97), I b (OR =13.26), II (OR = 36.62), III (OR = 4.57), IV (OR = 22.86), and V (OR = 1.19).

CONCLUSIONII fimA genotype of P. gingivalis followed by IV and I b were an important virulence factor that may account for the pathogenesis of chronic periodontitis, suggesting an increased pathogenic potential of these types.