幼儿猛性龋病原菌的分离鉴定

The Isolation and Identification of Pathogenic Bacteriafrom Rampant Caries in Children

目的 :确定幼儿猛性龋的优势病原菌 ,为其防治提供依据。方法 :采用细菌分离培养、形态学、生理生化学和DNAG +Cmol%测定方法 ,对 3 0名 2～ 5岁猛性龋患儿牙菌斑菌丛进行分离鉴定 ,采样部位为上颌患龋乳切牙龋损部位及邻近健康釉质表面 ,对照组的非猛性龋和无龋儿童则采集上颌乳前牙唇面颈 1/3处的菌斑。结果 :猛性龋儿童龋损部位变链菌和远缘链球菌的检出率及两个采样部位菌斑标本中变链菌和远缘链球菌的检出水平均显著高于非猛性龋和无龋儿童 (P <0 0 5 )。结论 :变链菌和远缘链球菌为幼儿猛性龋的优势病原菌。

Objective: In order to prevent rampant caries in children, the predominant pathogenic bacteria of rampant caries in children were defined. Methods: The pathogenic bacteria of rampant caries were isolated and identified in 30 children with rampant caries, aged from 2 to 5 years old. Samples were collected from the caries of labial surfaces of maxillary anterior deciduous teeth, including caries lesions and caries_free smooth enamel surfaces. Plaque were obtained from the cervical third areas of the maxillary labial anterior deciduous tooth surfaces in children without rampant caries and caries_free children and served as controls respectively. The isolates were identified by colony morphology, biochemical tests and DNA base contents (mol percent G+C).Results: The prevalence of Streptococcus mutans (S.mutans) and Streptococcus sobrinus (S. sobrinus) in the plaque of caries lesions and the proportions of S. mutans and S. sobrinus in the plaque of 2 sampling sites of children with rampant caries were all significantly higher than those of children without rampant caries and caries_free children (P<0.05).Conclusion:S.mutans and S.sobrinus are predominant pathogenic bacteria in rampant caries in children.