DEHYDRATED CULTURE MEDIA 105 



One pound of Bacto-Peptone Colloid Medium will make 17.4 liters of medium. 



ij. Infectious Diseases, 29:390:1921. ^ J. Bact., 37:121:1939. 



BACTO 



DUBOS BROTH BASE (B385) 



DEHYDRATED 



Bacto-Asparagine 2 g. 



Bacto-Casitone 0.5 g. 



Disodium Phosphate 2.5 g, 



Monopotassium Phosphate 1 g. 



Ferric Ammonium Citrate 50 mg. 



Magnesium Sulfate 10 mg. 



Calcium Chloride 0.5 mg. 



Zinc Sulfate 0.1 mg. 



Copper Sulfate 0.1 mg. 



Tween 80 0.2 g. 



Bacto-Dubos Broth Base is recommended for the preparation of a liquid 

 medium for the rapid cultivation of pure cultures of Mycobacterium tuberculosis. 

 It is prepared in accordance with the formula given by Dubos, Fenner and 

 Pierce.^ This is a modification of the original medium described by Dubos and 

 Davis^ and Dubos and Middlebrook.^ 



Liquid media have been used for the cultivation of tubercle bacilli for many 

 years. Generally the growth on these media appeared as a surface pellicle. Dubos* 

 reported rapid and submerged growth of M. tuberculosis in Long's Synthetic 

 Medium to which was added soya bean phosphatide and a polyoxyalkylene de- 

 rivative of sorbitan monostearate (Tween 60). Dubos and Davis,^ in a study of 

 factors influencing the growth of M. tuberculosis described, among other media, 

 a liquid medium containing Tween 80, an oleic acid ester, and albumin (serum 

 fraction V). In this liquid medium growth of the tubercle bacillus was obtained 

 in 3-5 days from dilute inocula. The addition of the albumin fraction V to the 

 medium facilitated the growth of tubercle bacilli from small inocula but did 

 not increase markedly the total amount of growth produced. Less pure prepara- 

 tions of the protein increased the amount of growth as well as initiated growth 

 from minute inocula. '^-^ The character of the growth obtained on this medium 

 was different from that obtained on liquid media previously described. Subsur- 

 face, readily dispersible growth was obtained, and pellicle formation occurred 

 only in old cultures. This type of growth was particularly valuable in obtaining 

 an even suspension of tubercle bacilli for use in mouse and guinea pig infection 

 tests and for other techniques requiring an even suspension of organisms. 



Dubos and Davis^ obtained typical diffuse cultures of acid-fast bacilli from 

 sodium hydroxide treated human sputa, and avian bacilli from animals experi- 

 mentally infected. Even though the medium was capable of supporting growth of 

 tubercle bacilli from pathological material, they cautioned against its indiscrim- 

 inate use in diagnostic work. Foley^-''' reported that a liquid medium similar to 

 that described by Dubos could be used successfully for the isolation of tubercle 

 bacilli from various pathologic materials, and that a combination of rapid culture 

 in this medium and guinea pig confirmation should result in a shorter period of 

 time required for diagnosis of tuberculosis. Goldie^ used the liquid medium for 

 the cultivation of tubercle bacilli from sputa treated with ammonium carbonate 

 and penicillin. Other laboratories,^ after thorough comparative study, reported 

 that the liquid medium as described by Dubos could not be recommended for 

 the clinical diagnosis of tuberculosis, confirming the statement of Dubos. 



