DEHYDRATED CULTURE MEDIA 123 



study evaluating the media employed for the cultural diagnosis of gonorrhoea 

 declared that the G C Medium Base enriched with Bacto-Hemoglobin and 

 Bacto-Supplement B yielded results in 24 hours comparable with those obtained 

 on the best plating media requiring a similar or longer incubation period. 



Wax^ used Bacto-G C Medium Base enriched with Bacto-Hemoglobin and 

 Bacto-Supplement B, with tyrothricin as a selective agent in the isolation of 

 Neisseria other than N. gonorrhoeae from the genito-urinary tract. 



For a complete discussion of the development of the cultural diagnosis of 

 gonorrhoea, including detailed recommendations for the collection of specimen, 

 inoculation of plates and observation and confirmation of results, reference 

 should be made to the discussion given under Bacto-Proteose No. 3 Agar, page 

 116-123. 



Since Bacto-G G Medium Base contains only 1 per cent Bacto-Agar, care 

 must be exercised not to penetrate through the surface during inoculation. 

 Following inoculation, plates should be incubated at 35-37 °C. for 24 hours. 

 Best results are obtained in an atmosphere of carbon dioxide obtained by one of 

 the procedures outlined under Bacto-Proteose No. 3 Agar, page 118. 



The enriched Chocolate Agar, using Bacto-G C Medium Base and Bacto- 

 Hemoglobin, is prepared in the following manner: 



Prepare a double strength G G Medium Base by suspending 7.2 grams in 100 

 ml. cold distilled water and steaming or boiling to dissolve the medium com- 

 pletely. At the same time prepare a double strength hemoglobin solution by 

 placing 2 grams Bacto-Hemoglobin in a dry flask and adding 100 ml. cold dis- 

 tilled water, while the flask is being agitated vigorously. The Bacto-Hemoglobin 

 suspension is shaken intermittently for 10-15 minutes to break up all aggregates 

 and effect complete solution. Both double strength solutions of G C Medium 

 Base and Bacto-Hemoglobin are sterilized in the autoclave for 15 minutes at 

 15 pounds pressure (121°G.). 



The sterile solutions are allowed to cool to 50-60° G. Add 1 per cent of Bacto- 

 Supplement A or Bacto-Supplement B, based on the final volume of medium, to 

 the double strength G G Medium Base (2 ml. per 100 ml. double strength 

 sterile agar base). Mix well and add an equal volume of double strength sterile 

 Bacto-Hemoglobin solution at 50-60° G. Mix well and distribute into sterile petri 

 dishes. Gaution: Do not add Bacto-Supplement A or Bacto-Supplement B to the 

 hemoglobin solution before mixing with the agar base. 



Best results will be obtained if the medium is prepared in advance so that 

 the surface of the medium is dry before inoculation. 



When the single strength medium, without enrichment, is desired, the medium 

 is rehydrated by suspending 36 grams Bacto-G G Medium Base in 1000 ml. cold 

 distilled water and heating to boiling to dissolve the medium completely. Dis- 

 tribute in tubes or flasks and sterilize in the autoclave for 15 minutes at 15 

 pounds pressure (121°G.). The final reaction of the medium without enrich- 

 ment will be pH 7.2. 



One pound of Bacto-G G Medium Base will make 12.6 liters of medium. 



^ Am. J. Syphilis Gonorrh. Venereal Diseases, ^Personal Communication 1947. 



33:164:1949. ^Personal Communication 1947. 



8 Diagnostic Procedures and Reagents, 3rd ^ Paper read at the annual meeting of the 



Edition: 30-1 07: 1 950. Am. Pub. Health Assoc, 1947. 



8 J. Venereal Disease Inform., 26:239:1945. « J. Venereal Disease Inform., 31:208:1950. 

 * Paper read at the annual meeting of the 



Canadian Pub. Health Assoc, 1947. 



