Objective      To investigate the distribution difference of fimA genotypes of Porphyromonas gingivalis (P. gingivalis) in chronic periodontitis patients living in plateau and plain environments.       Methods      Chronic periodontitis patients in the plateau (3 700 m altitude) and the plain (400 m altitude) were enrolled by stratified sampling

with 80 patients in each group. P. gingivalis in subgingival plaque samples were collected from the chronic periodontitis patients and was detected by 16S rRNA PCR. The fimA gene-specific primers were designed and the distribution of fimA genotypes of P. gingivalis in the patients was detected by PCR.       Results      The detection ratio of P. gingivalis was 96.25% in the plateau group

statistically higher than 87.5% in the plain group (P0.05). The distribution of 6 fimA genotypes in P. gingivalis-positive patients was as follows: type Ⅰ 35.1%

type Ⅰb 31.2%

type Ⅱ 85.7%

type Ⅲ 13.0%

type Ⅳ 20.8%

and type Ⅴ 0 in the plateau group

while 18.6%

30.0%

55.7%

11.4%

27.1%

and 0 in the plain group. The detection ratio of type Ⅱ fimA genotype was highest

and the plateau group was higher than the plain group (P0.05).       Conclusion      P. gingivalis with various fimA genotypes is present in the subgingival plaque samples from chronic periodontitis patients in the plateau environment

With higher detection rate than in the plain

and P. gingivalis with type Ⅱ fimA genotype is predominant

which may be associated with the development and progression of chronic periodontitis in the plateau.