A selective medium for the two major subgroups of the bacterium Streptococcus mutans isolated from human dental plaque and saliva.

A selective medium was developed on which both major subgroups of Strep. mutans (c/e/f and d/g) can be cultured and recognized on the basis of colonial morphology, Trypticase, yeast, cystine (TYC) agar was modified by adding separately autoclaved sucrose to a final concentration of 20 per cent and 0.1 unit/ml bacitracin (TYCSB). This medium yielded significantly higher counts of Strep. mutans than the widely used mitis-salivarius bacitracin (MSB) medium.