A Semi-Quantitative Determination of Streptococcus mutans Using Its Adherent Ability in a Selective Medium

A method differentiating the critical level of Streptococcus mutans in whole saliva was developed. The procedure is as follows: 100 μl whole saliva is inoculated into 2 ml of MSB broth, the test tube is set tilted at a 60° angle and incubated aerobically at 37 °C for 24 h. The degree of adherence is then scored. When the adherence score is + + +, S. mutans may be assumed to be present at a level higher than 105/ml of whole saliva. On the other hand, if adherence is scored – or + S. mutans is present at a level lower than 104/ml of whole saliva. The method is useful for handling many samples in preventive practice and epidemiological studies, because of its simplicity.