Which two tests are best for differentiating S. bovis from Streptococcus salivarius?

The best tests for differentiating S. bovis from Streptococcus salivarius are bile esculin and acid production from mannitol. S. bovis is known for its ability to hydrolyze bile esculin, leading to a color change in the medium due to the production of esculetin, which forms a dark complex with iron salts present in the medium. On the other hand, Streptococcus salivarius does not exhibit this characteristic and fails to grow or produce a color change in bile esculin agar.

In addition, S. bovis can ferment mannitol, leading to acid production, while Streptococcus salivarius typically does not ferment mannitol effectively. This clear difference in metabolic capabilities enables the laboratory to use these two tests as reliable indicators to differentiate between the two streptococcal species.

Understanding the biochemical properties and growth requirements of these bacteria is essential in microbiological diagnostics, emphasizing the importance of choosing the appropriate tests that can effectively highlight their distinctive features.