不同龋敏感儿童牙菌斑内口腔链球菌的PCR-DGGE分析

目的应用PCR-变性梯度凝胶电泳(DGGE)技术,分析不同龋敏感儿童牙菌斑内口腔链球菌菌群及其菌种组成的多样性。方法牙菌斑组织取自45例学龄前儿童,根据乳牙龋失补牙面(dmfs)指数分为无龋(dmfs=0)、中龋(dmfs=4~6)和高龋(dmfs>8)(n=15)。分别提取细菌总DNA,进行链球菌属rnp B特征序列的PCR扩增及DGGE分析,克隆、测序并与核酸序列数据库的序列进行比对。结果无龋儿童菌斑中口腔链球菌菌群的基因型分布均显著高于中龋和高龋儿童(P<0.05);变异链球菌群是高龋组中的优势菌群。结论PCR-DGGE技术结合rnp B基因克隆文库分析可较灵敏、直观地反映牙菌斑中链球菌属各菌群及其菌种的组成情况。

Analysis of oral Streptococci in dental plaque of different caries-susceptibile children by PCR-DGGE

Objective To study the diversity of oral Streptococci in dental plaque of different caries-susceptibile children by PCR-denaturing gradient gel electrophoresis(DGGE). Methods Total DNAs were extracted from the plaques of 45 pre-school children,15 in caries-free group(dmfs=0),15 in moderate-caries group(dmfs=4-6) and another 15 in caries-susceptive group(dmfs>8).Bacterial communities in the three groups were examined by PCR of rnp B and DGGE and by analyzing the sequences of the ribotypes.Results Significantly greater diversity in genetypes of Streptococcus oralis group was found in the caries-free group than the moderate-caries group and caries-susceptive group(P<0.05).Streptococcus mutans group was the predominant flora in caries-susceptive children.Conclusion PCR-DGGE method combined with rnp B clone library profiling is a sensitive and effective approach to resolve the population structure of oral Streptococci in microflora of dental plaque.