Lysine Iron Agar

Lysine Iron Agar

SKU: KM0122 Category:

Lysine iron agar is a differential medium for the detection of Salmonella spp. and other enteric pathogens on the basis of lysine decarboxylase and hydrogen sulphide production.
Lysine iron agar was originally developed by Edwards and Fife(1) for Salmonella arizonae detection.
The peptone and yeast extract provides the required nitrogen, carbon and vitamins.
Glucose is a fermentable carbohydrate.
L-lysine is used to detect lysine decarboxylase and lysine deaminase enzymes.
Sodium thiosulphate is reduced to hydrogen sulphide which is detected by the ferric citrate indicator. Sodium chloride maintains the osmotic balance.
Bromocresol purple is a pH indicator.
For use the medium is inoculated using a pure culture of the test organism which should be smeared onto the surface of the slope and stabbed into the butt of the medium.
For details of the many reactions that may arise during the use of this medium reference should be made to one of the many standard textbooks.

Additional Information


Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

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Product Description

Organisms Ref. No Slant / Butt / H2S
Escherichia coli NCTC 12241 Alkaline / Alkaline / –
Salmonella typhimurium NCTC 12023 Alkaline / Alkaline / +
Proteus mirabilis ATCC 29906 Red / Acid / –
Citrobacter freundii ATCC 8090 Alkaline / Acid / +
Enterobacter aerogenes NCTC 1006 Alkaline / Alkaline / –

Positive lysine decarboxylase reaction

Alkaline slant and alkaline butt

Negative lysine decarboxylase reaction
Alkaline slant and acid butt

Positive lysin deaminase reaction
Red slant

Negative lysine deaminase reaction
Purple slant

Hydrogen sulphide production
Blackening of medium

Recommended incubation: Aerobically at 35°C ± 2°C for 18-48 hours.