儿童猛性龋变链菌分离株的产酸性

Acidogenesis by Streptococcus mutans isolated from children with rampant caries

目的 :确定儿童猛性龋变链菌和远缘链球菌临床分离株的产酸性。方法 :采用酸度计和自动气相色谱仪比较儿童猛性龋、非猛性龋、无龋变链菌 (各 6株 )和远缘链球菌 (儿童猛性龋 6株 ,非猛性龋和无龋各 3株 )的临床株降低环境pH值的能力 (ΔpH)和乳酸产量 ,并以此推测其致龋力。结果 :远缘链球菌ΔpH及乳酸产量均高于变链菌 ,特别是在低pH水平下 ,二者差异更为显著 (P <0 .0 5 )。儿童猛性龋远缘链球菌分离株ΔpH和乳酸产量显著大于非猛性龋和无龋分离菌株 (P <0 .0 5 )。结论 :远缘链球菌的产酸能力强于变链菌 ;

AIM: To determine the acidogenicity of Streptococcus mutans and Streptococcus sobrinus isolated from children with rampant caries. METHODS: The strains were isolated and selected randomly from children with and without rampant caries and from caries-free children (6 S.mutans strains respectively; 6 S.sobrinus strains from children with rampant caries, 3 S.sobrinus strains from the rest respectively). Lactic production and terminal pH of the media were measured by auto gas chromatograph and pH electrode. RESULTS: Higher lactic production and lower terminal pH of media were obtained by S.sobrinus compared with S.mutans, especially at pH levels below 6.0 ( P <0.05). The ability to produce acid of S.sobrinus isolated from children with rampant caries was superior to that from children without rampant caries and from caries-free children ( P <0.05). CONCLUSION: S.sobrinus is more acidogenic than S.mutans. The acidogenicity of S.sobrinus isolated from children with rampant caries is enhanced.