DEHYDRATED CULTURE MEDIA 177 



reactions on this medium may differ from the reactions usually obtained by a 

 group of organisms since it contains free 1 -cystine which may give a positive 

 reaction by organisms considered negative by classical methods. 



Bacto-Motility Sulfide Medium is used in the proposed rapid method of 

 differentiating and identifying bacteria of the intestinal group described by 

 Hajna," to detect the capacity of an organism to produce hydrogen sulfide from 

 1 -cystine, and to determine motility. Motility is evidenced by presence of 

 diffuse growth away from tlie line of inoculation, non-motile organisms growing 

 only along the line of inocu'iation. Hydrogen sulfide producing organisms show 

 a blackening of the medium, blackening being confined to the inoculated portion 

 of the medium with non-mo ti'e organisms, but diffusing throughout the medium 

 with motile organisms. In this procedure the medium is dispensed in 4 ml. 

 amounts in 13 x 100 mm. tubes, sterilized and cooled in a verticle position. The 

 suspected colony on the primary plating medium is picked with a straight needle 

 and inoculated in succession, without securing additional inoculum, into Bacto- 

 Motility Sulfide Medium, to a depth of about a quarter of the column, and then 

 into Triple Sugar Iron Agar and H Broth. The Motility Sulfide Medium is in- 

 cubated at 30°G. overnight. 



The ability of the organism to hydrolyze urea is determined following observa- 

 tion of motility and hydrogen sulfide production. The Motility Sulfide Medium 

 culture is overlaid with 1 ml. of Eacto-Urea Broth, and incubated at 37 °C., for 

 not more than 6 hours. A positive urease reaction is indicated by a reddish purple 

 color forming in the Urea Broth. 



To rehydrate the medium, suspend 104 grams Bacto-Motility Sulfide Medium 

 in 1000 ml. cold distilled water. When the medium is thoroughly wetted, care- 

 fully heat to boiling to dissolve the medium completely. The medium requires 

 nearly constant agitation during the heating process. Dispense in 4 ml. amounts 

 in 13 X 100 mm. tubes and sterilize in the autoclave for 15 minutes at 10 pounds 

 pressure (117°C.). Final reaction of the medium will be pH 7.3. 



One pound of Bacto-Motility Sulfide Medium will make 4.3 liters of medium. 



iPub. Health Lab., 8:36:1950. 

 2 Pub. Health Lab., 9:23:1951. 

 ^Univ. Ky. Cir., 54:1942. 



BACTO 



H BROTH (B451) 



DEHYDRATED 



Bacto-Peptone 5 g. 



Bacto-Tryptone 5 g. 



Bacto-Beef Extract 3 g. 



Bacto-Dextrose 1 g. 



Sodium Chloride 5 g. 



Dipotassium Phosphate 2.5 g. 



Bacto-H Broth is recommended for the preparation of the "H" agglutination 

 antigen as used in the differentiation and identification of members of the 

 Salmonella group. It is prepared according to the formula described by Hajna 

 and Damon.^ This medium is used in the rapid method of differentiating and 

 identifying bacteria of the intestinal group as described by Hajna.^ The produc- 

 tion of the "O" type antigen and the elaboration of indole is also shown on this 

 medium. Hajna^ reported that the combination of Bacto-Peptone and Bacto- 

 Tryptone in this medium has proven excellent in every way. 



Serological analysis of the "H" and "O" antigens has been used as a practical 



