116 DIFCO MANUAL 



of uniform composition and provides a substrate which maintains the blood cells 

 in an excellent state of preservation, thus insuring typical hemolytic reactions. 

 Casmani'2 reported that a medium consisting of 2 per cent Bacto-Tryptose, 0.3 

 per cent Bacto-Beef Extract, 0.5 per cent sodium chloride, 1.5 per cent Bacto- 

 Agar and 0.03 per cent dextrose equalled fresh beef infusion base with respect 

 to growth of organisms. The small amount of carbohydrate, however, interfered 

 with hemolytic reactions unless the medium was incubated in an atmosphere of 

 carbon dioxide. 



To rehydrate the medium, suspend 33 grams of Bacto-Tryptose Blood Agar 

 Base in 1000 ml. cold distilled water and heat to boiling to dissolve the medium 

 completely. Distribute in tubes or flasks and sterilize in the autoclave for 15 

 minutes at 15 pounds pressure (121°G.). The final reaction of the sterilized 

 medium, before adding blood, will be pH 7.2. 



If Blood Agar is to be prepared immediately, the sterile agar base is cooled 

 at once to 45-50° C. and while still liquid, 5 per cent sterile defibrinated blood 

 is added aseptically. Mix thoroughly, avoiding incorporation of air bubbles, and 

 dispense into sterile petri dishes or sterile tubes as desired. Between 12 and 15 

 ml. of Blood Agar per 100 mm. petri dish is satisfactory. Blood Agar should be 

 incubated to insure sterility before use. 



One pound of Bacto-Tryptose Blood Agar Base will make 13,8 liters of fin- 

 ished basal medium or 14.5 liters of Blood Agar. 



ij. Bact., 43:33:1942. ''Am. J. Clin. Path., 17:281:1947. 



BACTO 



PROTEOSE NO. 3 AGAR (B65) 



DEHYDRATED 



Proteose Peptone No. 3, Difco 20 g. 



Bacto-Dextrose 0.5 g. 



Sodium Chloride 5 g. 



Disodium Phosphate 5 g. 



Bacto-Agar 15 g. 



Bacto-Proteose No. 3 Agar, enriched with Bacto-Hemoglobin and Bacto- 

 Supplement A or Bacto-Supplement B, is recommended for the cultural isola- 

 tion of Neisseria gonorrhoeae from chronic and acute cases of gonorrhoea in the 

 male and female and in other gonococcal infections. The medium permits excel- 

 lent growth of the gonococcus without overgrowth by contaminating organisms. 

 In a survey,^ under carefully controlled conditions, twelve media recommended 

 for the isolation of the gonococcus were compared. Bacto-Proteose No. 3 Agar 

 enriched with Bacto-Hemoglobin and Bacto-Supplement A compared very 

 favorably with other decidedly more complex media. A discussion of a 24 hour 

 medium for the cultural diagnosis of gonorrhoea is given under Bacto-G G 

 Medium Base on page 122. In the survey^ this 24 hour incubation medium gave 

 but slightly better results than Bacto-Proteose No. 3 Agar. 



The diagnosis and control of gonorrhoea have been greatly facilitated by im- 

 proved laboratory methods for detecting, isolating and studying A^. gonorrhoeae. 

 Foremost among these developments is the cultural method for detecting the 

 presence of the gonococcus in exudates and body fluids. The greater efficiency 

 of this procedure over the microscopic technique has established its indispensa- 

 bility in the routine diagnosis of gonococcal infections. The plating procedure 

 is not only more sensitive in indicating the presence of the gonococcus, but also 

 permits isolation of the organism for further study. Improved media developed 

 for identification of the isolated organisms simplify the procedure making it 



