A bile epét, a solubility oldékonyságot jelent. A bile solubility, mint az alábbi szemelvényből kitetszik, nem az epe (vízben, miegymásban) való oldékonyságát, hanem valamilyen anyagnak az epében való oldhatóságát jelenti.


BILE SOLUBILITY TEST
A. Purpose
The bile solubility test determines the ability of an organism to lyse in the presence of bile salts (sodium desoxycholate). It is used specifically to differentiate Streptococcus pneumoniae (bile soluble) from other alpha- hemolytic streptococci (bile insoluble).

B. Principle
1. Bile salts lower surface tension at the medium- membrane interface and also cause dearrangement of the cell membrance. However, S.pneumoniae produces an autolytic intracellular enzyme that causes the organism to rapidly autolyze when grown on artificial media. The role of bile salts is to accelerate this natural autolytic process by combining with the pneumococcal cell and activating its autolysin.
2. The bile solubility test may be done one of two ways: the tube bile solubility test, which requires a very heavy inoculum of a pure culture of the organism to be tested; or the plate bile solubility test, done directly on a plate of a fresh growing culture.


Az eljárás céljának ismertetése:

Introduction - Bile solubility provides presumptive identification of Streptococcus pneumoniae.

Principle - Surface active agents such as bile salts, saponins, and other cationic detergents alter the surface of S. pneumoniae, resulting in the activation of an autolytic enzyme. This enzyme is an amidase thats splits the muramic acid-alanine bond in peptidoglycan, resulting in lysis of the cell.

Media and reagents - Pure culture of suspect organism growing on agar plate, 2% bile solution (2% deoxycholate, 2% sodium lauryl sulfate, or 1% white Dreft can be used in place of bile).

Procedure - Add a loopful of bile solution to a visable colony growing on the surface of the plate. Incubate the plate, right side up, at 37 C for 30 minutes. Take care not to wash the colony away by agitating the plate. Examine the plate for absence or flattening of the colony.