老年人根面菌斑内氏放线菌临床分离株基因型多样性分析

The genotypic diversity of oral Actinomyces naeslundii of root caries in aged people

目的分析老年人根面菌斑中内氏放线菌临床株的基因型多样性,探讨内氏放线菌基因型与根面龋的关系。方法选择老年根面龋患者20例设为根面龋组,无根面龋老年人20例设为无龋组。根面龋组以暴露的无龋根面和根面龋损部位为取样位点,无龋组以暴露的根面为取样位点,刮取菌斑进行临床株的分离鉴定,并利用基因外重复回文序列聚合酶链反应(REP-PCR)分析内氏放线菌基因型的多样性。结果 2组共分离出内氏放线菌299株,选择156株进行REP-PCR分析,分离出61个不同的基因型。根面龋组无龋根面分离的57株内氏放线菌有25个基因型,根面龋损部位分离的34株有25个基因型,无龋组分离的65株有26个基因型:内氏放线菌基因型存在多样性。单个取样位点的基因型数目存在差异(P<0.05)。结论多种基因型的内氏放线菌参与了根面龋的发生。

Objective To investigate the genotypic diversity of Actinomyces naeslundii in aged people and the relationship between the genotypes of Actinomyces naeslundii and root caries.Methods According to the inclusion criteria,20 aged people with root caries and 20 without root caries were chosen into two groups for this study.Two sites were chosen in subjects with root caries： One site was the exposed sound root surface,and the other site was the root caries.In subjects without root caries the sampling site of root surface was exposed.Bacteria were cultured and then identified.Repetitive extragenic palindromic sequence-based polymerase chain reaction（REP-PCR） was used to analyze the genotypic diversity of the Actinomyces naeslundii clinic isolates.Results 299 strains were isolated from the groups,156 strains were chosen to analyze,belonged to 61 different genotypes.At the site of sound root surface in the subjects with root caries,there were 57 strains with 25 different patterns.At the site of root caries and of sound root surface in subjects without caries,there were 34 strains with 25 different patterns and 65 strains with 26 different patterns respectively.There was the genotypic diversity within Actinomyces naeslundii.There was significant difference in the genotypes in every individual site.Conclusion Many different genotypes of Actinomyces naeslundii concerned with occurrence of root caries.