FimA Virulence Genotypes Of Porphoromonas Gingivalis In The Patient With Chronic Periodontitis

Background and ObjectivePeriodontitis, a kind of chronic infective disease offending the gingival and periodontal tissues, is the main reason of lost teeth in adult. A number of studies have indicated that Porphyromonas gingivalis is the dominant bacteria in periodontitis tissues, and has obvious virulence or pathogenicity. P. gingivalis can interfere with the host's defensive ability via multiple mechanism, lead to destroy of periodontal tissues, and has a correlation with periodongtitis recurring or aggravating after treatment. The studies of this bacterial pathogenicity show that P. gingivalis has a series of factors which can escape from the effects of host's defensive mechanism and destroy host's tissues, such as pilus, outer membrance protein, ecto-ves, lipopolysaccharide and agglutinim. As one of the main surface structure of P. gingivalis, pilus mediates the interaction between P. gingivalis and the host, promotes bacteria adhering and setting in the target site, and inhibits host's defensive mechanism by inhibiting extracellular matrix-adhesion receptor to interrupt the information conduction from epithelium to host's immunocyte. In addition, pilin opypeptide also can activate polymorphonuclear, promote the interaction of fibrinogen-PMN, and increase fore-inflammation material . IL-8, which is a selective inducing neutrophil and monocyte chemotactic factor, however, assembling of a large number of neutrophi and monocyte aggravates local inflammatory reaction.FimA is a specific pilus subunit protein gene of P. gingivalis , within DNA of genes. Pilus FimA gene-codogenic proteins include pilin, adhesion protein and transfer protein that participates in making pilus subunit protein to permeate the cellular membrane. There are differences among different P. gingivalis FimA protein generated by different strain.This research selects the periodontitis patients in Henan province as the objects, studies the infective circumstance in subgingival plaque of patients and the correlation between the distribution of FimA virulence genotype of P. gingivalis and periodontitis, discusses and analyzes the relationship between the infection of P. gingivalis and periodontitis.MethodsIn accordance with Armitage diagnostic criteria of periodontitis, 52 chronic periodontitis patients were selected through random sampling as the objects, who visited the department of stomatology of Henan Province People's Hospital from July 2005 to March 2006. Among the objects, there are 34 males, aged 24 to 69 years with average age of 43.8, 18 females aged 26 to 62 with average age of 40.2. All objects in this experiment must be accord with: all over the body in a good condition, no system disease, no hereditary disease, no periodontal therapy in the last 6 months, no antibacterials taken in the last 3 months.First, the 52 objects were examined and the clinical observation indexes were record. Then, subgingival plaque samples in 104 sites of the 52 chronic periodontitis patients were collected, and the DNA of plaques were extracted by UNIQ-10 Bacteria kit and Chelex-100 assay; P. gingivalis were detected by 16SrRNA PCR, and prevalence of subtyping of FimA virulence genotypes Hand IV were assessed by PCR among the P. gingivalis positive patients.ResultP. gingivalis was detected in 40 Subgingival plaque samples among 52 Subgingival plaque samples in chronic periodontitis, and the detection rate of P. gingivalis was 76.9%. The detection rate of P. gingivalis in the site of 46mm. And there are statistical significance between them (P<0.05), which means that infection rate of P. gingivalis is high in Subgingival plaque in chronic periodontitis. It support that this bacterial has an important role in the disease process of chronic periodontitis, and PPD has the relevance with the detection rate of P. gingivalis. Therefore, samples in the deepest site in moderate or severe periodontal pocket should be selected if high detection rate of P. gingivalis was expected. Two virulence Genotypes among P. gingivalis positive patients were as fllows: 15 FimA type II (37.5%); 9 FimA type IV (22.5%). It means that FimA Virulence Genotypes of P. gingivalis have the genic polymorphism. There are no statistical significance (P>0.05) between the two assay, UNIQ-10 Bacteria kit and Chelex-100 assay, which are used to extract DNA of bacterial to identify P. gingivalis. However, later is simpler, faster and cheaper, and is used in extensive survey properly.Conclusion1.The detective rate of P. gingivalis in Subgingival plaque in chronic periodontitis was 76.9%, which means the infection rate of P. gingivalis is high in Subgingival plaque in chronic periodontitis. The PPD has the relevance with the detection rate of P. gingivalis. Therefore, samples in the deepest site in moderate or severe periodontal pocket should be selected if high detection rate of P. gingivalis was expected. 2. FimA Virulence Genotypes of P. gingivalis have the genic polymorphism.3. There is no statistical significance between the two assay, which are used to extract DNA of bacterial to identify P. gingivalis. However, compared withUNIQ-10 Bacteria kit, Chelex-100 assay is simpler, faster and cheaper in extracting DNA of bacteria, and is used in extensive survey properly.