DEHYDRATED CULTURE MEDIA 79 



tion of the organisms. Blood for blood culturing should always be taken prior 

 to the administration of the therapeutic agent. If drugs have been administered 

 their bacteriostatic effects should be neutralized. For example the addition 

 of p-aminobenzoic acid (PAB) in 5 mg. per cent to the medium will assure 

 the inactivation of any sulfa drug carried over with the inoculum. Bacto-Penase, 

 a concentrated purified penicillinase, should be added to the sterile cooled 

 medium used for blood culture if the patient is under penicillin therapy. Bacto- 

 Brain Heart Infusion with PAB and Agar with added Bacto-Penase is an ideal 

 medium for blood culture work. The small amount of agar present will give all 

 degrees of anaerobiosis, permitting the development of the obligate anaerobes 

 and microaerophiles as well as the aerobes. The PAB will inactivate any sulfa 

 drug, the added Bacto-Penase wdll inactivate any penicillin in the inoculum, 

 while 100 ml. of the medium itself will inactivate up to 1000 units of strepto- 

 mycin. 



For the detection of organisms from the blood of patients known to be under 

 sulfonamide therapy, Bacto-Brain Heart Infusion with PAB or Bacto-Brain 

 Heart Infusion with PAB and Agar are recommended. These media contain 

 5 mg. per cent of PAB which neutralizes the bacteriostatic effect of the sul- 

 fonamide present in the blood specimen. 



To rehydrate the medium, dissolve 37 grams of Bacto-Brain Heart Infusion 

 in 1000 ml. distilled water. Distribute in tubes or flasks and sterilize in the auto- 

 clave for 15 minutes at 15 pounds pressure (121°C.). The final reaction of the 

 medium will be pH 7.4. 



If the medium is not used the same day as prepared and sterilized, heat at 

 100°C. for several minutes to remove absorbed oxygen, and cool quickly without 

 agitation, just prior to inoculation. 



One pound of Bacto-Brain Heart Infusion will make 12.2 liters of medium. 



IJ. Dental Research, 1:205:1919. » J. Am. Med. Assoc, 110:1095:1938. 



3 Arch. Internal Med., 32:828:1923. ^^° Trans. N.Y. Academy Sciences, 9:52:1946. 



3 J. Infectious Diseases, 29:390:1921. ^ J. Milk and Food Tech., 13:226:1950. 



*J. Bact., 37:121:1939. 12 Science, 106:350:1947. 



6 J. Infectious Diseases, 63:122:1938. ^ ]. Bact., 54:70:1947. 



^ Am. J. Ophthalmol., 19:1060:1936. 1* J. Infectious Diseases, 74:131:1944. 



■^Am. J. Clin. Path., 9:1939: Tech. Suppl., ^^ Public Health Reports, 63:173:1948. 



3:20:1939. "Diagnostic Procedures and Reagents, 3rd 

 8 Am. J. Digestive Diseases, 13:105:1946. Edition: 452:1950. 



BACTO BACTO 



BRAIN HEART INFUSION BRAIN HEART INFUSION 



with PAB (B37A) with PAB and Agar (B37B) 



DEHYDRATED DEHYDRATED 



Two modifications of Bacto-Brain Heart Infusion widely used in blood culture 

 procedures are now available in dehydrated form. These media are especially 

 recommended for the detection of organisms in the blood of patients under sul- 

 fonamide therapy there has been included in the formula sufficient /?-amino- 

 benzoic acid (PAB) to give a final concentration of 5 mg. per cent. This 

 will neutralize the maximum amount of sulfonamide that might be carried 

 over into the medium with the blood inoculum, and thereby exert an inhibitory 

 effect upon pathogens inoculated into the medium. 



The formula for Bacto-Brain Heart Infusion with PAB is identical with that 

 of Bacto-Brain Heart Infusion except for the addition of 0.05 gram of p-amino- 

 benzoic acid per liter. To rehydrate the medium dissolve 37 grams of Bacto- 

 Brain Heart Infusion with PAB in 1000 ml. of distilled water. 



