272 DIFGO MANUAL 



pages 116 and 122. The medium suggested for the cultural detection of the 

 gonococcus by "Diagnostic Procedures and Reagents"^ of the American Public 

 Health Association is Bacto-G C Medium Base enriched with Bacto-Hemoglobin 

 and Bacto-Supplement B. These media may also be recommended for the isola- 

 tion of H. influenzae and H. ducreyi. For the isolation of P. tularensis a medium 

 prepared with Bacto-Hemoglobin and Bacto-Cystine Heart Agar, as discussed 

 on page 91, is recommended. 



Solutions of Bacto-Hemoglobin have the advantage of being sterilizable in the 

 autoclave. Bacto-Hemoglobin is used solely as an enrichment, and cannot be 

 employed as an indicator of hemolysis. For use as an enrichment in media, 2 

 grams of Bacto-Hemoglobin are dissolved in 100 ml. of distilled water. This 

 solution is best prepared by placing 2 grams of Bacto-Hemoglobin in a dry flask 

 and adding 100 ml. cold distilled water while the flask is being agitated vigor- 

 ously. The hemoglobin suspension is shaken intermittently for 10-15 minutes to 

 break up all aggregates and effect complete solution. It is sterilized in the auto- 

 clave for 15 minutes at 15 pounds pressure (121°C.). The sterile solution is 

 added, in equal proportions, to sterile double strength medium. When agar media 

 are prepared it is important to cool the melted agar and the hemoglobin solution 

 to 50-60°C. before the solutions are mixed, and the mixture should be agitated 

 to insure a perfect suspension of hemoglobin throughout the medium. Agar 

 media enriched with Bacto-Hemoglobin are similar to Chocolate Agar in 

 appearance. Broth media may be enriched in the same manner except that the 

 temperature of the mixture may be disregarded. 



^ J. Lab. Clin. Med., 16:166:1930. Diagnostic Procedures and Reagents, 3rd Edi- 



tion: 30: 107: 1950. 



BAGTO-BEEF BLOOD (B137) 



Bacto-Beef Blood is whole beef blood which has been desiccated and powdered. 

 It is an enrichment, capable of being sterilized in the autoclave, duplicating the 

 dilute whole blood (Preparation No. 3) as described by Spray^ for use in the 

 cultivation of hemoglobinophilic organisms. Bacto-Beef Blood is used solely as 

 an enrichment for culture media. It cannot be employed as an indicator of 

 hemolysis. 



Bacto-Proteose No. 3 Agar as discussed on page 116, enriched with Bacto-Beef 

 Blood, is well suited for propagation of the hemophilic bacteria. This enriched 

 medium possesses excellent growth-promoting properties. For the cultivation of 

 the gonococcus, however, Bacto-Hemoglobin should be employed as the enrich- 

 ment. 



When Bacto-Beef Blood is first dissolved in water it has the appearance of 

 laked blood. After it has been autoclaved there is a tendency for the soft coagu- 

 lum to settle. It is, therefore, advisable to maintain an even dispersion by gentle 

 agitation of the flask when the sterilized solution is added to the medium. After 

 addition of the solution to an agar medium, the mixture should be agitated to 

 secure an even suspension of the blood in the medium as described below. Agar 

 media enriched with Bacto-Beef Blood are similar to Chocolate Agar in appear- 

 ance. 



Bacto-Beef Blood is prepared for use by dissolving 2 grams of the powder 

 in 100 ml. of distilled water. It is then sterilized in the autoclave for 15 minutes 

 at 15 pounds pressure (121°C.). To prepare a chocolate or enriched agar, mix 

 equal parts sterile beef blood solution and sterile melted double strength agar, 

 under aseptic conditions. The temperature of both solutions should be between 

 50-60° C. at the time of mixing and they should be gently agitated to insure 



