Department of Preventive Dentistry, University of Granada, Spain.
Med Oral Patol Oral Cir Bucal. 2012 May 1;17(3):e495-500. doi: 10.4317/medoral.17592.
The aim of this study was to analyze possible horizontal transmission patterns of S. mutans among 6-7-yr-old schoolchildren from the same class, identifying genotypes and their diversity and relationship with caries disease status.
Caries indexes and saliva mutans streptococci and lactobacilli counts were recorded in 42 schoolchildren. Mutans streptococci colonies were identified by means of biochemical tests and all S. mutans strains were genotyped by arbitrarily primed polymerase chain reaction. A child was considered free of S. mutans when it could not be isolated in 3 samples at 1-week intervals.
S. mutans was isolated in 30 schoolchildren: 20 having one genotype and 10 two genotypes. Higher mutans streptococci and caries index values were found in those with two genotypes. Five genotypes were isolated in more than 1 schoolchild and one of these was isolated in 3 schoolchildren. Our results suggest that horizontal transmission may take place.
Schoolchildren aged 6-7 yrs may be the source of mutual transmission of S. mutans.
本研究旨在分析同一班级 6-7 岁学童间变形链球菌（S. mutans）的水平传播模式，鉴定基因型及其多样性，并分析其与龋齿状况的关系。
对 42 名学童进行龋齿指数、唾液变形链球菌和乳酸杆菌计数记录。采用生化试验鉴定变形链球菌菌落，并采用任意引物聚合酶链反应对所有 S. mutans 菌株进行基因分型。若在 3 周内 3 次间隔 1 周的样本中均未分离到 S. mutans，则认为该儿童无 S. mutans 感染。
30 名学童中分离出 S. mutans：20 名学童有 1 种基因型，10 名学童有 2 种基因型。具有 2 种基因型的学童变形链球菌和龋齿指数值更高。有 5 种基因型在 1 名以上学童中分离出，其中 1 种在 3 名学童中分离出。我们的结果表明可能存在水平传播。
6-7 岁学童可能是 S. mutans 相互传播的源头。
