Abstract:

Objective　To detect and distinguishStreptococcus mutans(S.mutans) andStreptococcus sobrinus(S.sobrinus) quickly in epidemiology and investigate the distribution ofS.mutansin the oral of children with rampant caries.Methods　De- signed minor groove binder (MGB) probes according to the gtf gene ofS.mutansandS.sobrinus. Detected 9 reference strains of Streptococcus mutansgroup byMGB probes in real time and after cultivation. Evaluated the results of these twomethods. 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 distinguishedS.mutansandS.sobrinusfrom each other using MGB probes. Though the fluorescence occurred earlier inS.mutansthan inS.sobrinus, they had the same results in nature. In 92 children with ram- pant caries, the detective ratio ofS.mutanswas 96.7% and that ofS.sobrinuswas 32.6%. All the sampleswhich could detect S.sobrinuswere positive forS.mutans.Conclusion　The primers and probe designed fromgtf genes ofS.mutansandS.sobri- nuscan amplify the target sequence and distinguish them from each other in real time.

Key words: Streptococcus mutans;Streptococcus sobrinus, minor groove binder probes, rampant caries, real time detec- tion