102 DIFGO MANUAL 



isms such as streptococci, pneumococci, meningococci and other microorganisms. 



The fact that dextrose (<i-glucose) is a readily available source of energy, 

 utilized by a large number of organisms, makes Dextrose Broth an important 

 medium in any laboratory. Dextrose Broth can be recommended to give rapid 

 growth and hasten the early development of attenuated forms. A liquid medium 

 containing dextrose is especially adapted to primary culture in the isolation of 

 pathogenic bacteria. Bacto-Dextrose Broth contains 0.5 per cent dextrose along 

 with Bacto-Tryptose. This medium is superior to most Infusion-Peptone Dextrose 

 Broths for the cultivation of a large variety of bacteria, including the pathogenic 

 cocci, and has the further advantage of greater uniformity. Bacto-Dextrose Broth 

 is especially suited for use in the preparation of Rosenow's Dextrose Brain Broth^ 

 as described for the isolation of streptococci. The value of Bacto-Dextrose Broth 

 is greatly increased for the cultivation of organisms like streptococci, pneumo- 

 cocci, meningococci, gonococci, etc., if 0.1 per cent agar be incorporated in the 

 medium as discussed on page 77 under Bacto-Brain Heart Infusion. 



Bacto-Dextrose Broth is recommended for use in the tube dilution method of 

 testing the sensitivity of microorganisms to antibiotics. Waisbren, Carr and Dun- 

 nett^ showed that Bacto-Dextrose Broth, Bacto-Tryptose Phosphate Broth or 

 Bacto-Nutrient Broth were suitable media for comparative sensitivity test studies 

 while a medium containing a soy bean peptone inhibited the action of Neomycin, 

 Aureomycin, Terramycin and Polymyxin against the test organism. 



To rehydrate the medium, dissolve 23 grams of Bacto-Dextrose Broth in 1000 

 ml. of distilled water. Distribute in tubes and sterilize in the autoclave for 15 

 minutes at 15 pounds pressure (121°C.). Final reaction of the medium will be 

 pH 7.2. 



For best results Bacto-Dextrose Broth should be freshly prepared. If the 

 medium is not used the same day as sterilized, heat in boiling water or flowing 

 steam for a few minutes to remove absorbed oxygen, and cool quickly without 

 agitation, just prior to inoculation. 



One pound of Bacto-Dextrose Broth will make 19.7 liters of medium. 



1 J. Dental Research, 1:205:1919. 2 Am. J. Clin. Path., 21:884:1951. 



BACTO 



TRYPTOSE BROTH (B62) 



DEHYDRATED 



Bacto-Tryptose 20 g. 



Sodium Chloride 5 g. 



Bacto-Dextrose 1 g. 



Thiamine Hydrochloride 0.005 g. 



Bacto-Tryptose Broth is prepared without extract or infusion of meat and is 

 recommended as a general laboratory medium for the cultivation of discriminat- 

 ing pathogenic as well as saprophytic bacteria. Huddleson^ used a broth contain- 

 ing 2 per cent Bacto-Tryptose as an enrichment medium in the isolation of 

 Brucella from man. McCullough, Mills, Herbst, Roessler and Brewer^ reported 

 that the addition of thiamine, dextrose and iron salts increased the growth of 

 B. suis. Sanders and Huddleson^ showed that the addition of dextrose and 

 thiamine hydrochloride to the medium resulted in the stimulation of the growth 

 of all species of Brucella. Bacto-Tryptose Broth is prepared according to the 

 formula of Tryptose Dextrose Vitamin B Broth as given in the "Diagnostic 

 Procedures and Reagents"^ of the American Public Health Association and is 

 particularly recommended as a blood enrichment medium, with the addition of 

 sodium citrate, for isolation of Brucella from febrile and afebrile patients accord- 



