Use Bactidrop Desoxychocolate to differentiate between bile soluble Streptococcus pneumoniae and other insoluble alpha-hemolytic streptococci.Ready-to-use: Liquid reagentEasy to interpret:Spot Test Positive Test - Colony disintegration within 30 minutesNegative Test - Colony remains intact within 30 minutesTube Test Positive Test - Clearing of Test suspension within 3 hours; Control suspension remains turbidNegative Test - Test and Control suspensions remain turbid within 3 hoursThe bile solubility test is based on the observation that when 10% desoxycholate is applied S. pneumoniae cells lyse, while other streptococci and gram-positive cocci do not. Bile salts cause a cell membrane derangment and also lower surface tension at the medium-membrane interface4,5.S. pneumoniae possesses an autocatalytic enzyme that lyses the organism’s own cell wall during cell division. This autolytic intracellular enzyme causes the organism to undergo rapid autolysis when cultivated on artificial medium6. Goebel and Avery stated that the action of bile salts is independent of the autolytic enzyme7. Dubos and Hirsch found that bile salts inactivate the naturally occurring autolytic enzyme either by the alteration or the removal of a normal autolytic inhibitor from the pneumococcal cells8.This reagent contains 10% w/v desoxycholic acid sodium, ethanol, sodium Merthiolate and demineralized water.Not all products are available for sale in all territories. Please inquire.Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.