感染根管中牙龈卟啉单胞菌fimA基因多态性研究

fimA genetic polymorphism of Porphyromonas gingivalis in periapical periodontitis

目的研究根尖周炎患牙感染根管内牙龈卟啉单胞菌(P.gingivalis)不同fimA基因型的分布情况。方法收集200例感染根管内样本,经DNA抽提后使用16S r DNA PCR方法检测P.gingivalis。在P.gingivalis检出阳性样本中,根据各fimA基因型的特异引物,采用PCR检测不同fimA基因型菌株的分布,并通过Pearsonχ2检验对不同fimA基因型与临床症状进行相关性分析。结果感染根管中P.gingivalis的检出率为48%,其中79例样本只检测到1种fimA基因型P.gingivalis菌株(82.3%);12例样本检测到2种或2种以上fimA基因型P.gingivalis(12.5%)。各fimA基因型P.gingivalis的检出情况:Ⅰ型29.2%、Ⅰb型8.3%、Ⅱ型37.5%、Ⅲ型14.6%、Ⅳ型19.8%。各型fimA基因与临床症状之间无统计学相关性(P<0.05)。结论感染根管内P.gingivalis的fimA基因存在基因多态性,其中以fimAⅡ型P.gingivalis菌株检出率最高,其次为Ⅰ型和Ⅳ型。

Objective To investigate the distribution of different fimA genotypes of Porphyromonas gingivalis（ P. gingivalis） strains in root canals among periapical periodontitis patients. Methods A total of 200 samples of infected root canals with periapical periodontitis were collected. After DNA was extracted from the samples,16S rRNA gene-based polymerase chain reaction（ PCR） method was applied to identify the appearance of P. gingivalis. Among the P. gingivalis-positive samples,fimA type-specific primers were used to amplify the target DNA fragments by PCR,aiming to obtain the information about the distribution of different fimA genotypes.Pearson χ~2 test was performed to investigate the correlation between fimA types and symptoms. Results The presence of P. gingivalis was demonstrated in 48% of total number of infected root canals. A single fimA genotype was detected in 79 samples（ 82. 3%）. Combinations of at least 2 different genotypes were detected in 12 cases（ 12. 5%）. The distribution of six fimA genotypes among the P.gingivalis-positive samples was as follows： type Ⅰ,29. 2%; type Ib,8. 3%,type Ⅱ,37. 5%; type Ⅲ,14. 6%; type Ⅳ,19. 8%and type Ⅴ,0. 00%. There was no significant correlation between fimA genotypes and symptoms of periapical infection（ P 0. 05）.Conclusion There is fimA genetic polymorphism of P. gingivalis in infected root canals from different patients with periapical periodontitis. Relevance ratio of type Ⅱ fimA is the highest,followed by type Ⅰ and Ⅳ.