Abstract
MSB agar was compared with TYCSB agar regarding with the selectivity and the recovery of mutans streptococci from fresh plaque samples in 68 Japanese children 2-10 years old. The yields of freshly isolated strains of mutans streptococci on TYCSB agar were significantly higher than on MSB agar (p<0.05). However, the ratios of the number of mutans streptococci to that of the total microorganisms on TYCSB agar was lower than on MSB agar (p<0.01). Furthermore, extraneous microorganisms were too crowded on TYCSB agar to calculate the number of mutans streptococci in 5 subjects out of the 57 subjects in which mutans streptococci was detected on the MSB agar.
The number of mutans streptococci calculated by MBS agar (p<0.0001) was found to relate more strikingly to the number of decayed tooth surfaces than the number calculated by TYCSB agar (p<0.05).
These results suggest that MSB agar was better in usual practice in. Japanese children to monitor the number of mutans streptococci and to isolate fresh clinical strains of mutans streptococci.
