286 DIFCO MANUAL 



BILE PRODUCTS 



B AGTO-OXG ALL ( B 1 28 ) 



Bacto-Oxgall is a dehydrated fresh bile, prepared especially for use in making 

 bile media. It is manufactured from large quantities of fresh bile by rapid 

 evaporation of the water content. The use of Bacto-Oxgall insures a regular 

 source of supply independent of the slaughterhouse, and assures a degree of 

 uniformity impossible to obtain with fresh materials, eliminating the uncertainty 

 of variable results. The equivalent of fresh bile is attained in a 10 per cent solu- 

 tion of Bacto-Oxgall. 



Bacto-Oxgall is recommended for use in the preparation of media for the 

 detection and propagation of intestinal organisms. Specifically, a large number 

 of bile-containing media have been devised for use in the bacteriological exami- 

 nation of water. Bacto-Oxgall is most frequently used in the preparation of 

 culture media for water analysis. The Ninth Edition of "Standard Methods for 

 the Examination of Water and Sewage"^ recommends Brilliant Green Lactose 

 Bile Broth as discussed on page 37, for confirming positive presumptive tests of 

 coliform bacteria in water. In this text Brilliant Green Lactose Bile Agar, as 

 discussed on page 52, is described as a selective agar medium for the direct plate 

 count of the coliform group. Bacto-Oxgall is recommended as an ingredient of 

 both these media. Brilliant Green Lactose Peptone Bile 2 per cent is also ap- 

 proved in "Standard Methods for the Examination of Dairy Products"- for 

 detecting the presence of coliform bacteria in milk. 



Solutions of Bacto-Oxgall, added to broth cultures of pneumococci, produce 

 lysis of the cells, and can therefore be used in bile solubility tests for differentiat- 

 ing pneumococci from the bile-insoluble streptococci. The general procedure of 

 the bile solubility test is to add one part of a sterile 10 per cent solution of Bacto- 

 Oxgall to nine or ten parts of culture. Evans^ and McKinney* have used Bacto- 

 Oxgall for this purpose. Greey^ reported excellent results using dry Bacto-Oxgall 

 sprinkled directly on Blood Agar plates. According to this procedure pneumococ- 

 cus colonies are dissolved and disappear entirely, but leave evidence of their 

 presence by means of the fixed blood cells in the clear medium. Colonies of 

 Streptococcus viridans are not dissolved or otherwise altered. Bacto-Oxgall is also 

 used in solution for the enrichment of blood cultures. 



Bacto-Oxgall has been used in the preparation of a selective medium for fungi. 

 Littman^ described an agar medium for the isolation of pathogenic fungi, em- 

 ploying Bacto-Oxgall, crystal violet and streptomycin as inhibiting agents for 

 bacteria. A complete discussion of this medium is given on page 240. 



^Standard Methods for the Examination of ^ J. Bact., 31 1423: 1936. 



Water and Sewage, gth Edition, 1946. * J. Bact., 27:373:1934. 



"Standard Methods for the Examination of ^ J. Infectious Diseases, 64:206:1939. 



Dairy Products, 9th Edition, 1948. ^ Science, 106:109:1947. 



BAGTO-BILE SALTS (B129) 



Bacto-Bile Salts was originally developed for use in the Lactose Bile Salt Agar 

 of MacConkey,^ one of the best known of the plating media for the isolation of 

 organisms of the colon-typhoid group. As originally described by MacConkey, 

 the medium was a peptone lactose, or glucose, agar containing 0.5 per cent 

 sodium glycocholate. Bacto-Bile Salts fulfilled the requirements of the original 

 sodium glycocholate. However, in recent studies, we have developed Bacto-Bile 

 Salts No. 3 which has been found to be more suitable than the Bacto-Bile Saitb. 

 previously employed in the MacConkey Agar. 



