母子口腔中变形链球菌基因型的对照研究

目的：分析高龋、无龋儿童及其母亲口腔中变形链球菌（S．mutans）菌株的基因型，探讨S．mutans基因型与致龋活性的关系。方法：试剂盒法提取细菌染色体DNA，对20名儿童（高龋组10名，无龋组10名）及其母亲的共800株S．mutans临床分离株进行AP—PCR基因型分析。结果：高龋儿童携带的S．mutans基因型数目多于无龋儿童（P〈0．05），高龋儿童的母亲携带的S．mutans基因型数目显著多于无龋儿童的母亲（P〈0．01），高龋儿童母亲的DMFT值显著高于无龋儿童母亲（P〈0．01），高龋组和无龋组的共有基因型数目无统计学差异（P〉0．05）。结论：高龋个体比无龋个体携带更多的S．mutans基因型，个体携带的S．mutnm基因型数目与其致龋活性有关。

A control study of S.mutans genotype in the oral cavity of mothers-children pairs

Objective:To study the relationship between genetic diversity within S.mutans and dental caries.Methods:Isolates of S.mutans were obtained from 10 caries active children and their mothers,and were originally isolated on mitis-salivarious-bacitracin agar.A total of 800 isolates were biochemically confirmed as S.mutans.Chromosomal DNA was extracted from those isolates with an extraction kit.By AP-PCR,the genetic diversities of S.mutans were examined respectively in 10 caries active children,10 caries-free children,and their mothers.DNA fingerprints were obtained by electrophoresis on 15 g/L agarose gel and analyzed for genotypics similarities.Results:The number of distinct genotypes of S.mutans harbored in caries active children were,on average,greater than that presented in children without caries(P<0.05);and such number harbored in mothers of caries active children were also greater than that presented in mothers of caries-free children(P<0.01).Mothers of caries active children had significantly higher DMFT scores than mothers of caries-free children(P<0.01).Conclusion:The number of distinct genotypes of S.mutans harbored in caries active indivicluals was greater than the number of genotypes present in individuals without caries.The genotypes of isolates might relate to differences in caries susceptibility.