Kligler Iron Agar

LAB 59

Description

A differential medium for the recognition of enteric pathogens their ability to ferment glucose and/or lactose, and liberate sulphi Fermentation liberates acid, with or without gas, turning phenol indicator yellow. Fermentation of glucose only, is followed reversion in pH on the slope, from initial acidity to final alkalinity (red colour), but not in the anaerobic conditions of the butt, which remains acid (yellow). Fermentation of lactose as well as glucose, produces acidity in both slope and butt (yellow). Liberation of sulphide results in the formation of iron sulphide (blackening of either slope or butt).

Method of reconstitution

Weigh 49 grams of powder and mix with 1 litre of distilled water. Bring to the boil with frequent stirring to dissolve completely. Dispense into tubes and sterilise for 15 minutes at 121˚C. Cool in a slanted position such that slopes are formed over deep butts approx. 3cm in depth.

Appearance: Reddish brown agar. pH: 7.4±0.2

Inoculation

Subcultures for further identification are picked from the centre of isolated colonies on selective media and streaked across the slant and stabbed deep into the butt of tubes of Kligler Iron Agar.

Incubation: 37˚C aerobically for 18-24 hours.

1.26

Incubation: 37˚C aerobically for up to six weeks.

Storage: Tightly capped containers - up to 3 months at 15-20˚C in the dark.

References:

Kligler, I.J. (1917). A Simple Medium for the Differentiation of Members of the Typhoid - Paratyphoid Group. Am. J. Publ. Hlth, 7:1042-1044.

Bailey, S.F. and Lacey, G.R. (1927). A modification of the Kligler Lead Acetate Medium. J. Bact. 13:182-189.