不同龋敏感儿童变异链球菌临床分离株合成胞外多糖能力的实验研究

目的比较不同龋敏感儿童口腔中变异链球菌的临床分离株合成胞外多糖能力的差异。方法以高龋、中龋和无龋儿童口腔中分离得到的变异链球菌为实验菌株,常规复苏、增菌,配制相同浓度的菌悬液,按菌液与含1%蔗糖的BHI液体培养基1：10（v/v）比例接种细菌,37℃厌氧培养24h后,分别收集水溶性葡聚糖和水不溶性葡聚糖,用蒽酮法进行定量分析。结果儿童高、中龋患者口腔中分离出的变异链球菌临床分离株以及国际标准菌株合成胞外多糖能力明显高于无龋者口腔中分离出的变异链球菌,差异具有统计学意义（P〈0.05）。结论高龋儿童口腔中变异链球菌临床分离株具有高致龋性。

Ability to synthesize water-soluble and-insoluble glucans of Streptococcus mutans isolated from children with different caries susceptibility

Objective To investigate the ability to synthesize water-soluble and-insoluble glucans of Strepto-coccus mutans isolated from the children with different caries susceptibility.Methods The difference to synthesize glucans was measured and compared among high caries-susceptible group,middle caries-susceptible group and caries-free group in order to find the correlation between carious experiences and abilities to synthesize glucans.Results The ability to synthesize water-soluble and-insoluble glucans of Streptococcus mutans isolated from the high caries-susceptible children and middle caries-susceptible group are significantly higher than that isolated from caries-free group（P0.05）.We also found that the cariogenicity of strains isolated from one individual with cariesactive risk was diversified.Conclusion There is relationship between caries and the high cariogenecity of Streptococcus mutans strains.