猛性龋儿童变链菌分离株耐酸性实验研究

Aciduricity of mutans streptococci isolates from the children with rampant caries.

目的 :确定猛性龋儿童变链菌和远缘链球菌临床株的耐酸性。方法 :采用紫外分光光度计比较猛性龋、非猛性龋、无龋儿童变链菌 (各 6株 )和远缘链球菌 (猛性龋儿童 6株 ,非猛性龋和无龋儿童各 3株 )临床株在体外不同初始 pH条件下的生长情况。 结果 :初始 pH 4.5～ 5 .5条件下 ,各组变链菌生长抑制程度均明显大于远缘链球菌(P <0 .0 5 )。初始pH 4.5条件下 ,猛性龋儿童远缘链球菌分离株耐酸性明显强于非猛性龋和无龋儿童分离菌株(P <0 .0 5 )。结论 :远缘链球菌的耐酸性强于变链菌 ;

Objective: To determine the aciduricity of Streptococcus mutans and Streptococcus sobrinus isolates taken from children with rampant caries. Methods:The strains were isolated and selected randomly from children with rampant caries and from children without rampant caries and from caries-free children (6 S.mutans respectively, 6 S.sobrinus from children with rampant caries, 3 S.sobrinus from the rest respectively). Their growths at various initial pH were measured by ultraviolet spectrophotometer in vitro. Results: At pH 4.5~5.5, the growth inhibition of S.mutans strains were higher than that of S.sobrinus strains ( P <0.05). At pH 4.5, the ability to tolerate acid of S.sobrinus isolates taken from children with rampant caries was superior to that from children without rampant caries and from caries-free children ( P < 0.05 ). Conclusions:The aciduricity of S.sobrinus was higher than that of S.mutans. The aciduricity of S.sobrinus isolates taken from children with rampant caries was stronger.