【摘要】 目的　分析牙龈卟啉单胞菌细菌基因型及其重要毒力因子胶原酶基因PrtC的遗传异质性 ,了解细菌遗传变异与其致病性的相关性。方法　对从不同牙周炎患者口腔中分离出的牙龈卟啉菌进行DNA指纹分析 ,参考菌株为PgATCC332 77。通过PCR反应 ,检测临床菌株中是否存在特异性的胶原酶基因片段 (548bp)。并通过酶切鉴定和DNA序列分析 ,了解PrtC基因遗传多样性的变化。结果　 80株牙龈卟啉菌共获得 7种基因型 (Ⅰ～Ⅶ )。所有 2 4株临床菌株和参考菌株PgATCC332 77中均扩增出特异性的胶原酶基因片段。对照菌株中没有得到相应的产物。 4株细菌的序列分析结果与国外的报道相比较 ,发现一些基因序列存在差异 ,出现 6个核苷酸碱基缺失。结论　临床分离的牙龈卟啉菌中可检测到多种基因型 ,且具有个体差异 ,这些菌株具有合成胶原酶的能力 ,不同菌株胶原酶基因之间存在遗传异质性的变化更多还原

【Abstract】 Objective To investigate the genotypic characterization of Porphyromonas gingivalis(Pg) and the heterogeneity of a potential virulence factor PrtC. Methods Arbitrarily primed polymerase chain reaction(AP PCR) was applied to 80 Pg strains isolated from 24 unrelated Chinese periodontitis patients. PCR reaction was used to detect a fragment of the collagenase gene(PrtC gene). To evaluate the sequence heterogeneity of the Pg PrtC genes, sequence analysis of four PrtC gene of clinical isolates was performed. Results Random primer OPA 05 and OPA 17 distinguished 7 AP PCR profiles(ⅠthroughⅦ). The majority of the strains belonged to type Ⅶ which accounted for 25 8%. A 548bp fragment of PrtC gene was detected from 24 clinical strains. The PCR products were verified by the restriction endonucleases PstI and PvuI . Sequence analysis showed 4 PrtC genes were heterogeneous in their nucleotide composition and differed from reference strain Pg 53977. Conclusions The results demonstrated genetic diversity existed among these clinical strains isolated from Chinese periodontitis patients and the PrtC genes are heterogeneous in their nucleotide sequence.更多还原