不同龋敏感儿童牙菌斑内微生物群落的分子生态学特点

摘要

背景：玻璃离子水门汀充填的儿童牙体仍易发生继发龋现象，与充填材料表面牙菌斑内复杂微生物群落具有密切关系，而传统微生物学方法无法获知牙菌斑微生物的重要信息。目的：利用先进的现代分子生态学技术解析不同龋敏感儿童玻璃离子水门汀表面牙菌斑内微生物群落结构与重要致龋微生物的数量水平。方法：选择3-5岁儿童24名，按乳牙龋失补牙面指数不同分为无龋组、中龋组和高龋组，每组8名。采集各组儿童全口牙面菌斑，利用变性梯度凝胶电泳进行微生物群落多样性分析与微生物种群鉴定，利用荧光原位杂交考察致龋微生物Streptococcus spp.的数量分布，利用实时定量PCR考察重要致龋菌Streptococcus mutans占总菌的相对数量。结果与结论：无龋组牙菌斑内微生物群落的多样性显著高于中龋组和高龋组(P <0.05)，中龋组和高龋组中大量富集的某些微生物可能在龋病发展过程中起重要作用。3组样本共检出16个微生物菌属，Streptococcus spp.和Actinomycesspp.可能是高龋组中重要的致龋微生物。Streptococcus spp.和Streptococcus mutans在高龋组中所占比例显著高于无龋组和中龋组(P <0.01)。综合来看，研究采用的分子生态学技术可以较好反映牙菌斑内与致龋过程密切相关的复杂微生物群落。%BACKGROUND:Children teeth filed with glass ionomer cement are stil susceptible with secondary caries, which is in close relationship with complex microbial community in dental plaque on the surface of glass ionomer cement. Traditional microbial methods are incapable of getting important information towards dental plaque microbes. OBJECTIVE:To analyze microbial community structure and numerical level of caries-induced microbes in dental plaque on the surface of glass ionomer cement for different caries-susceptible children. METHODS:Twenty-four children (age: 3-5 years) were divided into the caries-free, caries-positive, and caries-active children groups by the decayed, missing and filed index. With eight individuals in each group, their dental plaques were sampled for microbial community analysis. Denaturing gradient gel electrophoresis was employed to make clear the microbial community diversity and species identity in dental plaque of the caries-free, caries-positive, and caries-active children groups. Fluorescentin situ hybridization was used to investigate the numerical level of the caries-induced microbeStreptococcus spp. Quantitative PCR was carried out to analyze relative quantity ofStreptococcusmutans in total bacteria. RESULTS AND CONCLUSION:Compared with the caries-positive and caries-active children groups, microbial community diversity among samples was significantly higher in the caries-free group. Microbes abound in the caries-positive and caries-active groups might act important roles in the development of caries.Streptococcus spp. and Actinomyces spp. might be important caries-induced microbes in the caries-active group. The ratios ofStreptococcus spp. andStreptococcus mutans in total bacteria were significantly higher in the caries-free group than those in the caries-free and caries-positive groups. In summary, molecular ecology technologies can wel reflect caries-related complex microbial community in dental plaque.