Species-specific PCR method for identification of Streptococcus downei.
OBJECTIVE
To establish a rapid method to differentiate Streptococcus downei and S. sobrinus by multiplex PCR.


RESULTS
A PCR primer pair specific to S. downei was designed on the basis of the nucleotide sequence of the dextranase gene of S. downei NCTC 11391T. The primer pair specifically detected S. downei, but none of the other mutans streptococci (16 strains of six species). The PCR procedure was capable of detecting 1 pg of genomic DNA purified from S. downei NCTC 11391 and as few as 14 CFU of S. downei cells. The mixture of primer pairs specific to each S. downei (this study) and S. sobrinus (Igarashi et al. 2000) detected only the strains of these two species among all the mutans streptococcal strains, and concomitantly differentiated the two species by species-specific amplicons of different lengths.


CONCLUSIONS
The present PCR method is highly specific to S. downei and is useful for detection and identification of S. downei.


CONCLUSIONS
Multiplex PCR using dextranase gene primers is a useful method for simultaneous detection and differentiation of S. downei and S. sobrinus.
Igarashi
T
T
Departments of Oral Microbiology Pediatric Dentistry, Showa University School of Dentistry, Tokyo, Japan. igatakes@dent.showa-u.ac.jp
Asaga
E
E
Murai
C
C
Sasa
R
R
Goto
N
N
D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D003910:Dextranase / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D005798:Genes, Bacterial; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013291:Streptococcus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*
D004269:DNA, Bacterial; D003910:Dextranase