小沟聚合物探针实时检测变形链球菌和远缘链球菌

目的　寻求一种快速检测变形链球菌(S.mutans)和远缘链球菌(S.sobrinus)的方法,研究变形链球菌群在儿童猛性龋患者口中的分布。方法　设计并合成针对S.mutans和S.sobrinus葡糖基转移酶基因(gtf)的特异性引物和小沟聚合物探针(MGB探针),对9株变形链球菌群参考菌株直接提取DNA及扩增纯培养后提取DNA分别进行检测,比较二者检测结果的异同。采集92例猛性龋儿童菌斑样本,用MGB探针进行实时检测。结果　采用MGB 探针可以特异性地鉴别S.mutans和S.sobrinus,直接检测和扩增纯培养后的定性检测结果完全一致,前者荧光出现的时间略迟。92例猛性龋患儿中S.mutans检出率为96.7%,S.sobrinus检出率为32.6%,所有检出S.sobrinus的菌斑样本均可检出S.mutans。结论　采用特异性MGB探针方法可以对菌斑中S.mutans和S.sobrinus进行实时检测, 提高检测效率。

MGB Probes Detect Streptococcus Mutans and Streptococcus Sobrinus in Real Time

Objective To detect and distinguish Streptococcus mutans (S.mutans) and Streptococcus sobrinus (S.sobrinus) quickly in epidemiology and investigate the distribution of S.mutans in the oral of children with rampant caries.Methods Designed minor groove binder (MGB) probes according to the gtf gene of S.mutans and S.sobrinus. Detected 9 reference strains of Streptococcus mutans group by MGB probes in real time and after cultivation. Evaluated the results of these two methods. 92 dental plaques from pre-school children with rampant caries were detected in real time with MGB probes.Results The primers could amplify the target sequences specificity and distinguished S.mutans and S.sobrinus from each other using MGB probes. Though the fluorescence occurred earlier in S.mutans than in S.sobrinus, they had the same results in nature. In 92 children with rampant caries, the detective ratio of S.mutans was 96.7% and that of S.sobrinus was 32.6%. All the samples which could detect S.sobrinus were positive for S.mutans. Conclusion The primers and probe designed from gtf genes of S.mutans and S.sobrinus can amplify the target sequence and distinguish them from each other in real time.