不同龋敏感儿童变形链球菌临床分离株产酸、耐酸能力的实验研究

Study on the ability of acidogenicity and aciduricity of Streptococcus mutans isolated from children with different caries susceptibility

目的:比较不同龋敏感儿童口腔中变形链球菌的临床分离株产酸和耐酸能力的差异。方法:以高龋、中龋和无龋儿童口腔中分离得到的变形链球菌为实验菌株,常规复苏、增菌,配制相同密度的菌悬液,加入含5%蔗糖、不同pH值(以0.5为间隔,pH4.0～7.0)的BHI液体培养基中厌氧(80%N2、10%H2、10%CO2)培养48 h后,采用pHS-3C型精密酸度计,测定培养物上清的终末pH值,比较细菌的产酸能力(△pH);将相同菌液浓度的变形链球菌临床分离株菌悬液分别在不同pH(以0.5为间隔,pH4.0～7.0)的BHI液体培养基中培养48 h后,用紫外分光光度计测定540 nm处吸光度,比较细菌的生长情况。结果:儿童高、中龋患者口腔中分离出的变形链球菌临床分离株以及国际标准菌株的产酸和耐酸能力明显高于无龋者口腔中分离出的变形链球菌,差异具有统计学意义(P<0.05)。结论:高龋儿童口腔中变形链球菌临床分离株具有高致龋性。

Objective： To investigate the acidogenicity and aciduric ability of Streptococcus mutans isolated from the children with different caries susceptibility. Methods： The acidogenic and aciduric ability of Streptococcus mutans strains isolated from children was investigated. Acidogenicity ability was compared among high caries-susceptible group, middle caries-susceptible group and caries-free group. Results： The acidogenicity and aciduric ability of Streptococcus mutans isolated from the high caries-susceptible children and middle caries-susceptible group were significantly higher than that isolated from caries -free group（ P 〈 0.05 ）. Conclusion： The high cariogenecity of Streptococcus mutans strains isolated from caries-active children shows a close relationship with the high acidogenecity and aciduric ability of the isolated Streptococcus mutans strains.