The relationship between prevalence of pathogenicity islands genes of Porphyromonas gingivalis and chronic periodontitis

Objective: To investigate PG0836, PG0838, and PG0839 genes of Porphyromonas gingivalis (P. gingivalis) in subgingival plaque of the chronic periodontitis patients, and find out the relationship between the prevalence of these three genes and the periodontal clinical parameters.

Methods: A total of 270 subgingival plaque samples were collected from 90 chronic periodontitis (CP) patients. The periodontal clinical parameters including the probing depth (PD), clinical attachment loss (CAL), and bleeding on probing (BOP) were estimated. The extracted DNA from the P.gingivalis positive samples was amplified with the specific primers designed to obtain the PG0836, PG0838, and PG0839 genes respectively. Statistical analyses including descriptive statistic and Chi square test were performed using SPSS11.0 software package.

Results: In the patients with subgingival plaque positive for P.gingivalis, there were 133 (66.17%), 50 (24.88%), and 56 (27.86%) sites positive for the PG0836, PG0838, and PG0839 genes respectively. A higher positive rate of PG0839 was observed in the sites with BOP than that without BOP (28.35% versus 14.29%, χ²=5.91, P<0.05). The positive rate of PG0839 in the sites with moderate and severe PD was higher than that in the sites with mild PD (P<0.05). There was no significant relationship among the prevalence of PG0836 or PG0838 with PD, CAL, and BOP.

Conclusions: The findings suggest that the PG0839 gene may have influence on the virulence of P. gingivalis. Supported by National Natural Science Foundation of China (Grant No.30772427).