The bile solubility test with S.pneumoniae (cultivation under anaerobic conditions, see here). Positive test result: dissolved colonies of Streptococcus pneumoniae on blood agar.

Pneumococcal cells lyse in the presence of sodium desoxycholate (bile salts). It may be performed using a cell suspension on a slide or in a tube or by applying the reagent (10% sodium desoxycholate solution) directly to the colony. The bile solubility test is used to differentiate Streptococcus pneumoniae from alpha-hemolytic Streptococcus spp..