DEHYDRATED CULTURE MEDIA 91 



other selective agents. Roseburg, Epps and Clark^ reported that Bacto-Brain 

 Heart Infusion with 2 per cent agar was more satisfactory than 1 per cent Dex- 

 trose Infusion Agar for the isolation and cultivation of Actinomyces israeli. 

 Incubation in an atmosphere of 5 per cent carbon dioxide was required for best 

 results. The addition of sheep blood to the medium offered no growth advantage. 

 HowelP used Bacto-Brain Heart Infusion to which was added 2 per cent Bacto- 

 Agar and 10 per cent sterile defibrinated horse blood for the cultivation of 

 Histoplasma capsulatum. A selective medium for the isolation of this organism 

 was prepared by adding 40 micrograms streptomycin and 20 units penicillin 

 per ml. of medium. In comparison with a Blood Agar similarly prepared from 

 Potato Dextrose Agar, the Brain Heart Infusion Agar gave a greater number of 

 positive isolations. Incubation at room temperature was more efficient than at 

 37° C. Colonies of H. capsulatum isolated on Brain Heart Infusion Agar must be 

 transferred to a medium such as Potato Dextrose Agar to obtain the character- 

 istic tuberculate chlamydospores typical of this fungus. Conant^ recommended 

 that a plate of Bacto-Brain Heart Infusion Agar be streaked and incubated at 

 37° G. under anaerobic conditions with the addition of 5 per cent carbon dioxide 

 to obtain growth of the microaerophilic A. bovis in culturing this organism from 

 infected mucous membranes and subcutaneous tissues. 



Kotcher, Robinson and Miller* compared various media for the isolation of 

 H. capsulatum from tissues of experimentally infected mice. Their results showed 

 that Brain Heart Infusion Blood Agar gave the highest percentage recovery of 

 H. capsulatum from the tissues of the infected mice. 



Bacto-Brain Heart Infusion Agar contains 0.2 per cent Bacto-Dextrose, mak- 

 ing it unsatisfactory for the determination of typical hemolytic reactions when 

 enriched with blood. Bacto-Heart Infusion Agar, Bacto-Tryptose Blood Agar 

 Base or Bacto-Blood Agar Base, as discussed on pages 87, 115 and 88, should 

 be used in preparing Blood Agar for the determination of typical hemolytic 

 reactions. 



To rehydrate the medium, suspend 52 grams Bacto-Brain Heart Infusion Agar 

 in 1000 ml. cold distilled water. Heat to boiling to dissolve the medium com- 

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

 at 15 pounds pressure (121°G.). 



A selective medium for fungi is prepared by adding 20 units penicillin and 

 40 micrograms streptomycin per ml. sterile liquid medium, at 50-55 °C. Final 

 reaction of the medium will be pH 7.4. 



One pound of Bacto-Brain Heart Infusion Agar will make 8.7 liters of 

 medium. 



1 J. Infectious Diseases, 74:131:1944. Edition :452: 1950. 



a Public Health Reports, 63:173:1948. * J. Bact., 62:613:1951, 



• Diagnostic Procedures and Reagents, 3rd 



BACTO 



CYSTINE HEART AGAR (B47) 



DEHYDRATED 



Beef Heart, Infusion from 500 g. 



Proteose Peptone, Difco 10 g. 



Bacto-Dextrose 10 g. 



Sodium Chloride 5 g. 



/-Cystine, Difco 1 g. 



Bacto-Agar 15 g. 



Bacto-Cystine Heart Agar, enriched with Bacto-Hemoglobin, is recommended 

 for the cultivation of Pasteurella tularensis. The use of this medium is suggested 



