中文摘要：

目的：分析维吾尔族高龋和无龋儿童变形链球菌临床分离株表面蛋白A区基因遗传多态性与其黏附能力的关系。方法：通过细菌贴壁法进行维吾尔族儿童高龋组（dmft≥5）和无龋组（dmft=0）变链菌临床株黏附试验。选取黏附能力较强和较弱的菌株,提取细菌DNA,经PCR扩增其表面蛋白A区编码基因spaP-a后,利用限制性内切酶HaeⅢ进行限制性片段长度多态性分析。结果：高龋组黏附能力（33.92±8.79）%强于无龋组（27.53±7.45）%,差异有统计学意义（P〈0.05）。经HaeⅢ酶切后,高黏附力组和低黏附力组变链菌均出现了A、B两种基因型,且在两组菌株中的分布情况不同,A基因型在高黏附力组居多,B基因型在低黏附力组居多,差异有统计学意义（P〈0.05）。测序证实spaP-a基因的特异性碱基突变引起酶切位点改变而产生基因多态性。结论：维吾尔族不同龋敏感儿童变链菌临床株spaP-a基因具有得遗传多态性可能是其黏附能力出现差异的原因之一。

英文摘要：

Objective：To analyse the relationship between genetic polymorphism and its adhesion ability in Streptococcus mutans clinical isolates of surface protein A Uygur high caries and caries-free children.Methods：Uighur children high caries group（dmft≥5）and caries-free group（dmft=0）were performed clinical strains of Streptococcus mutans adhesion test by bacteria adherent method.We selected the adhesion ability of stronger and weaker strains.The genome DNA was extracted,and the spaP-a was amplified by PCR.Genetic diversity was assessed by restriction fragment-length polymorphism（RFLP）with restriction endonucleases HaeⅢ.Results：Adhesion ability of high-caries group was stronger than the caries-free group（33.92 8.79%v.s.27.53 7.45%）,the difference was statistically significant（P〈0.05）.Two different patterns A and B of spaP-a RFLP among strains were revealed after the amplified product was digested with HaeⅢ.The distributions of two genotypes（A and B）in the clinical strains with different adherent abilities differed significantly（P〈0.05）.A genotype was the majority of the high adhesion force group.Genotype B was mostly in the low adhesion of group.The sequencing DNA testified that the specific base mutation would lead to multiple kinds of genotype resulted.Conclusion：Uighur different caries sensitive children of Streptococcus mutans clinical strains spaP- a gene with genetic polymorphism may be one of the reasons for a discrepancy between the its adhesion ability.