不同龋敏感儿童口腔不同基因型变异链球菌临床分离株在不同pH条件下产生GTF能力的比较研究  

A comparative study of GTF activity of Streptococcus mutans with different genotype isolated from children with different caries experience under different pH conditions

作　　者：施俊[1] 王志刚[1] 刘兴容[1] 

机构地区：[1]泸州医学院附属口腔医院口腔内科,四川泸州646000

出　　处：《牙体牙髓牙周病学杂志》2013年第8期519-522,510,共5页Chinese Journal of Conservative Dentistry

基　　金：四川省教育厅课题基金资助项目(2002A070)

摘　　要：目的:探讨不同龋敏感儿童口腔变异链球菌不同基因型菌株在不同pH条件下产生GTF的能力。方法:从不同龋敏感儿童口腔变异链球菌中选取66株临床分离株,常规复苏、增菌并配制相同密度的菌悬液后,接种于不同pH值(以0.5为间隔,pH 5.0～7.0)的含2.5 g/L葡萄糖和0.05%Tween 80的TYC培养基中厌氧培养18 h;采用Somogyi法测定还原糖含量,计算酶活性。结果:在同一pH条件下,不同龋敏感儿童口腔变链菌GTF活性的差异具有统计学意义(P<0.05),龋敏感性越高,GTF活性越大;同一龋敏感儿童口腔变链菌不同基因型菌株GTF活性的差异也具有统计学意义(P<0.05),GTF活性随基因型的增加而增加;当pH 5.5时,高龋、中龋儿童携带一种基因型菌株GTF活性显著下降(P<0.05)。结论:不同龋敏感儿童口腔变异链球菌不同基因型菌株在不同pH条件下GTF活性不同,携带基因型越多的菌株GTF活性越高。[ Abstract] AIM： To investigate the glucosyltransferase （GTF） activity of Streptococcus mutans （S. mutans） with different genotype isolated from children with different caries experience under different pH conditions. METHODS ： 66 strains of S. rnutans isolated from dental plaques of children with different caries experience were cultured. Bacterial suspension was adjusted to A540 nm= 1.0, then 100 μL of the suspension was inoculated to 10 mL TYC at different pH ranging from 5.0 to 7.0 containing 0.25% （w/v） glucose and 0.05% （w/v） Tween80 respectively for 18 h at 37 ℃. Somogyi method was used to measure GTF activity. RESULTS： There were significant differences in GTF activity among the strains isolated from children with different caries susceptibility in the same pH value （P 〈 0.05）, higher GTF activity was produced by the strain with higher cariogenecity and higher GTF activity was found in the strain with more genotypes. GTF activity of a genotype strain decreased with the decrease of pH value from 7 to 5. CONCLUSION： The S. mutans strain with more genotypes has higher GTF activity and higher cariogenecity.

关 键 词：龋敏感性 乳牙 变异链球菌 基因型 不同pH值 葡糖基转移酶(GTF) 

分 类 号：R780.2[医药卫生—口腔医学]