INGREDIENTS OF CULTURE MEDIA 277 



by H. influenzae. In addition, this enrichment contains crystal violet which sup- 

 presses growth of many of the common contaminants on the final medium. In 

 gonococcal isolations, these contaminants, if permitted to develop, may interfere 

 with the growth and detection of the gonococcus. 



Bacto-Supplement A is used in one per cent concentration in either solid or 

 liquid media containing Bacto-Hemoglobin. It is added aseptically after the 

 medium has been sterilized in the autoclave and cooled below 50°C. 



The use of this enrichment in media is discussed in detail under Bacto-G G 

 Medium Base, page 122 and Bacto-Proteose No. 3 Agar, page 116. 



Bacto-Supplement A is supplied in packages of six bottles of 5 ml. each. 



BAGTO-GHAPMAN TELLURITE SOLUTION (B291) 



Bacto-Chapman Tellurite Solution is a 1 per cent solution of potassium 

 tellurite prepared and standardized especially for use with Bacto-Mitis Salivarius 

 Agar, as discussed on page 154. The final medium is prepared by adding exactly 

 1.0 ml. to 1000 ml. of sterile melted Mitis Salivarius Agar at 50-55 °G., mixing 

 thoroughly and pouring into plates at once to obtain the proper selectivity. The 

 resulting selective medium duplicates that described by Chapman.^'- It permits 

 the isolation of Streptococcus mitis, S. salivarius and enterococci from grossly 

 contaminated specimens, other organisms generally being inhibited. Bacto-Chap- 

 man Tellurite Solution is also used in the preparation of PPLO Enrichment 

 Broth as discussed on page 82. 



Bacto-Chapman Tellurite Solution is supplied in packages of six ampuls of 

 5 ml. each. The solution must be stored in a glass stoppered container free from 

 organic matter. 



^ Am. J. Digestive Diseases, 13:105:1946. 3 Trans. N. Y. Acad. Sciences, 10:45:1947. 



BAGTO-TELLURITE BLOOD SOLUTION (B139) 



Bacto-Tellurite Blood Solution is defibrinated beef blood to which one per 

 cent potassium tellurite has been added. This mixture is prepared expressly for 

 use in the isolation of Corynebacterium diphtheriae. To 100 ml. sterile medium 

 prepared from Bacto-Dextrose Proteose No. 3 Agar (as discussed on page 147), 

 are added 5 ml. Bacto-Tellurite Blood Solution with aseptic precautions. This 

 mixture is heated to 75-80° G. until it takes on the appearance of Chocolate 

 Agar, then cooled to 50° C, poured into previously sterilized petri dishes, and 

 allowed to solidify. The surface of the medium is streaked with the suspected 

 diphtheritic material and the plates are then incubated at 35-37°G. for 24-48 

 hours. 



Surface colonies of C. diphtheriae on the Tellurite Agar are black in color, 

 slightly raised, and may have entire or irregular margins. Most contaminating 

 organisms fail to grow on the complete medium due to its inhibitory action. 



Bacto-Tellurite Blood Solution is not sterile, and cannot be recommended for 

 use except as described above. The tellurite present prevents growth of micro- 

 organisms and, during the heating at 75-80° C. in preparation of the medium, 

 contaminating organisms are killed or are inhibited by the potassium tellurite 

 during the incubation period. It is recommended that plates be inoculated the 

 same day as prepared. 



Bacto-Tellurite Blood Solution is supplied in single bottles or in packages 

 of six bottles of 25 ml. each. 



