SOME BIOLOGICAL PROPERTIES OF STREPTOCOCCUS-MUTANS ISOLATED FROM HUMAN MOUTHS, WITH REFERENCE TO THE CORRELATION WITH SEROTYPES

Many strains (> 70 per cent) of serotype e Streptococcus mutans, in addition to those of serotype c (> 90 per cent) fermented melibiose, indicating that the fermentation of this sugar is not a criterion for distinguishing these serotypes. Strains of serotype c, e and f Strep. mutans gave rise to small, rough, raised and adherent colonies on mitis-salivarius agar, and were non-peroxidogenic and non-haemolytic on sheep blood agar. However, those of serotype d and g formed a marked zooglea around the colony, and were peroxidogenic and alpha haemolytic on sheep blood agar. These properties will be useful in distinguishing the two subgroups within the species of Strep. mutans. © 1979.