The bile solubility test is used to determine the ability of bacterial cells to lyse in the presence of bile salts, within a specified time and temperature.
S. pneumoniae
possesses an autolytic enzyme, an amidase, which lyses the cell’s own wall
during division. The addition of bile salts (sodium deoxycholate) activates the
autolytic enzyme and the organisms rapidly autolyse. Other α-haemolytic
streptococci do not possess such an active system and therefore do not dissolve
in bile. The bile solubility test may be performed in two different ways:
- using a cell suspension or
- by applying the Bile solubility Reagent directly to the colony.
Posted by Dr. Tim Sandle