DEHYDRATED CULTURE MEDIA 183 



BACTO 



MALONATE BROTH (B395) 



DEHYDRATED 



Ammonium Sulfate 2 g. 



Dipotassium Phosphate 0.6 g. 



Monopotassium Phosphate 0.4 g. 



Sodium Chloride 2 g. 



Sodium Malonate 3 g. 



Bacto-Brom Thymol Blue 0.025 g. 



Bacto-Malonate Broth is liquid medium prepared with materials of known 

 chemical composition, with ammonium sulfate and sodium malonate as the only 

 source of nitrogen and carbon. It is prepared according to the formula described 

 by Leifson^ and used for the differentiation of members of the AerobacteT' 

 Escherichia group. 



The ability of members of the Aerobacter group to utilize malonate as a source 

 of carbon in a medium of known chemical composition, and the inability of 

 members of the Escherichia group to grow in this medium was pointed out by 

 Leifson. A pH indicator, brom thymol blue, was incorporated in the medium. 

 Aerobacter, utilize malonate as a source of energy, produce an alkaline reaction, 

 and change the color of the medium to blue. Escherichia, not capable of utilizing 

 malonate, fail to grow, leaving the medium unchanged. 



To rehydrate the medium, dissolve 8 grams Bacto-Malonate Broth in 1000 ml. 

 distilled water. Sterilize in the autoclave for 15 minutes at 15 pounds pressure 

 (121°C.). Avoid introduction of carbon and nitrogen from other sources. Final 

 reaction of the medium will be pH 6.7. 



One pound of Bacto-Malonate Broth will make 56.7 liters of medium. 

 ij. Bact., 26:329:1933. 



BACTO 



PHENOL RED TARTRATE AGAR (B90) 



DEHYDRATED 



Bacto-Peptone 10 g. 



Sodium Potassium Tartrate 10 g. 



Sodium Chloride 5 g. 



Bacto-Agar 15 g. 



Bacto-Phenol Red 0.024 g. 



Bacto-Phenol Red Tartrate Agar is a solid tube medium valuable in the 

 differentiation and identification of members of the Salmonella (paratyphoid) 

 group. Brown, Duncan and Henry^ observed that the members of the paratyphoid 

 group varied in their ability to attack sodium tartrate, and incorporated this 

 principle in a medium for subdividing the group. Jordan and Harmon^ claimed 

 that the medium of Brown, Duncan and Henry failed to give sharp differentiation, 

 and devised a medium which possessed the advantage of being more definite in 

 its differentiation. On this medium an acid reaction is produced by Salmonella 

 typhimurium, S. enteritidis, S. choleraesuis, S. ab or tivo equina, S. typhosa, 

 Escherichi coli and Proteus vulgaris strains, while the S. schottmuelleri and S. 

 paratyphi strains produce an alkaline reaction. 



Bacto-Phenol Red Tartrate Agar duplicates the medium of Jordan and 

 Harmon. It is used unslanted, and is inoculated by stabbing-. Observations are 

 made at 24 and 48 hour intervals. An acid reaction is mdicated by the develop- 



