儿童猛性龋病原菌母子传播研究

目的 :探讨幼儿猛性龋病原菌母子传播途径。方法 :随机选择可获得变形链球菌群 (MS)纯培养的 2～ 5岁猛性龋、非猛性龋及无龋儿童母子各 10对 ,进行DNA指纹实验 ,检测儿童牙菌斑和母亲唾液中MS菌株的遗传相似性 ,并检查母亲唾液MS水平。结果 :猛性龋儿童MS菌株基因型与母亲的一致性为 70 % ,与非猛性龋和无龋儿童(均为 6 0 % )无显著差异 ;但猛性龋儿童MS基因型数目显著多于非猛性龋和无龋儿童 (P <0 0 5 )。猛性龋儿童母亲唾液变链菌水平与非猛性龋和无龋儿童母亲相似 ,但唾液远缘链球菌水平及DMFT均数显著高于无龋儿童母亲。结论 :母亲是儿童MS的主要来源 ;幼儿猛性龋与母亲的DMFT计数及唾液远缘链球菌水平成正相关 ,母子传播对幼儿猛性龋的发生具有一定作用。

A Study on Transmission of Pathogenic Bacteria of Rampant Caries from Mothers to Children

OBJECTIVE: In order to prevent rampant caries in children, the transmission from mothers to children of pathogenic bacteria of rampant caries will be investigated in this study. METHODS: By using fingerprint technique, the genetic diversities of Streptococcus mutans(S. mutans) were examined respectively in 10 children with rampant caries, 10 children without rampant caries S. mutans, 10 2-year-old caries-free children, and their mothers. The levels of S. mutans in saliva of mothers were also examined. For fingerprinting, chromosomal DNA of isolates obtained from plaques of these children and from saliva of their mothers were digested with restriction endonuclease HindIII and examined by electrophoresis on 0.7% agarose gel. DNA fingerprints were obtained and analyzed for genotypic similarities. RESULTS: The DNA fingerprint patterns showed that the proportion of children whose genotypes of S. mutans matched their mothers in the children with rampant caries was 70%, which is similar to that in the children without rampant caries and the caries-free children (60% respectively). The number of distinct genotypes of S. mutans harbored in children with rampant caries was, on average, greater than the number of genotypes present in children without rampant caries and caries-free children (1.7, 1.2 and 1.1 respectively, P < 0.05). Mothers of children with rampant caries had similar levels of S. mutans in saliva as those mothers of children without rampant caries and caries-free children. However, mothers of children with rampant caries had significantly higher DMFT scores and higher levels of Streptococcus sobrinus (S. sobrinus) in saliva than the mothers of caries-free children did. CONCLUSION: In all child groups, mothers were probably the main source of infection with S. mutans. Rampant caries in children is associated with DMFT scores and levels of S. sobrinus in saliva of mothers. In the initiation of rampant caries experienced by a child, the transmission of pathogenic bacteria from mothers to children may be the main source.