RÉSUMÉ
砄bjective:To investigate the consistency of Streptococcus mutans and Streptococcus sobrinus isolates identified by colony morphology,biochemical tests and DNA base content analysis.Methods:46 clinical isolates (30 of S.mutans and 16 of S.sobrinus ) were identified by colony morphology,biochemical tests and determination of DNA base contents with reversed phase high performance liquid chromatography. S.mutans Ingbritt and S.sobrinus 6715 were used as the controls. Results:The DNA contents (G+C mol%) of S.mutans and S.sobrinus clinical isolates, identified by colony morphdogy and biochemical test, were 37.52 and 45.19 respectively,consistent with the expected 36～38 and 44～46 mol percent of G+C.Conclusion: S.mutans and S.sobrinus isolates,identified by colony morphology and biochemical tests ,were consistent with the DNA G+C content analysis. S.mutans and S.sobrinus can be easily and reliably identified by colony morphology and biochemical tests.