DEHYDRATED CULTURE MEDIA 165 



BACTO 



KLIGLER IRON AGAR (B86) 



DEHYDRATED 



Bacto-Beef Extract 3 g 



Bacto-Yeast Extract 3 g 



Bacto-Peptone 15 g 



Proteose Peptone, Difco 5 g 



Bacto-Lactose 10 g 



Bacto-Dextrose 1 g 



Ferrous Sulfate 0.2 g 



Sodium Chloride 5 g 



Sodium Thiosulfate 0.3 g, 



Bacto-Agar 12 g 



Bacto-Phenol Red 0.024 g 



l^acto-Kligler Iron Agar is a most useful differential tube medium in the study 

 of the Gram-negative intestinal microorganisms. It combines the principles of 

 Russell Double Sugar Agar and Lead Acetate Agar into one medium which per- 

 mits a differentiation of the Gram-negative rods both on the basis of their ability 

 to ferment dextrose or lactose, and on their ability to produce hydrogen sulfide. 

 It differentiates the lactose-splitting organisms from the lactose nonfermenters, 

 distinguishes Salmonella typhosa from the other Salmonella and the Shigella 

 groups and differentiates S. paratyphi (paratyphoid A) from S. schottmuelleri 

 and S. enteritidis. Kligler Iron Agar is recommended to identify further pure 

 cultures of colonies picked from primary plating media such as MacConkey Agar, 

 S S Agar, Bismuth Sulfite Agar and others. 



Kligler's^ original medium was a soft Nutrient Agar containing dextrose, 

 Andrade indicator and lead acetate. While experimenting with this medium and 

 other combinations, Kligler discovered that Russell's medium containing Andrade 

 indicator and lead acetate gave a good differentiation, and later^ recommended 

 it as being satisfactory for differentiation of the typhoid, paratyphoid and dysen- 

 tery groups. Bailey and Lacey^ made a study of such a medium in an attempt to 

 simplify it and to select a more suitable indicator. They found that phenol red 

 was particularly adaptable and recommended that it be used as the indicator of 

 hydrogen ion concentration. A similar medium, including saccharose and incorpo- 

 rating Bacto-Tryptone as a nutrient, with ferrous sulfate and thiosulfate as the 

 indicator of hydrogen sulfide production, was developed by Sulkin and Willett.'* 

 They found such a medium to be unique in its ability to give rapid clear-cut 

 reactions. A complete discussion of this medium is given under Bacto-Triple 

 Sugar Iron Agar, page 166. 



Bacto-Kligler Iron Agar is prepared with phenol red as an indicator of the 

 production of acid, and ferrous sulfate as an indicator of hydrogen sulfide pro- 

 duction. This combination of ingredients gives sensitive, distinct clear-cut reac- 

 tions. 



For typical cultural reactions in 18 hours, it is recommended that tubes of 

 Kligler Iron Agar be inoculated heavily with growth from a solid culture medium 

 by smearing over the surface of a slant and stabbing in the butt. If inoculated 

 from a suspension of organisms, or from broth culture, typical reactions of hydro- 

 gen sulfide production, and reversion, may not be obtained until 36-40 hours 

 at 37°C. To obtain true differential cultural reactions of this medium it is neces- 

 sary to have a pure culture. In inoculating directly from isolation media such as 

 MacConkey Agar, S S Agar or Bismuth Sulfite Agar plates, select well isolated 

 colonies and pick only the very center of the colony. If there is any question as 

 to the ability to obtain a pure culture from a certain colony, it is recommended 



