KM0160 – Simmons Citrate Agar (MFA) (VP)

//KM0160 – Simmons Citrate Agar (MFA) (VP)

KM0160 – Simmons Citrate Agar (MFA) (VP)

This medium can be used as a screening method for the differentiation of enterobacteriaceae based on the ability of some species to utilise citrate as a sole source of carbon. It is often used as a screening test for Klebsiella pneumoniae (positive reaction) while Escherichia coli is negative.

Species that metabolize citrate as their sole source of carbon and ammonium as the sole source of nitrogen cause an increase in alkalinity of the medium resulting in a colour change from green to blue due to the presence of the pH indicator bromthymole blue.

Additional Information

Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

Prepared Medium Appearance

Dehydrated Medium Colour

Prepared Medium Colour

Dehydrated PH

Prepared PH

Product Description

OrganismRef. No.Result
Citrobacter freundiiATCC 43864Growth, blue media
Klebsiella pneumoniaNCTC 9633Growth, blue media
Escherichia coliNCTC 12241Inhibited/ partially inhibited, no colour change

Formula*

FORMULA*g/L
Magnesium Sulphate0.2
Ammonium dihydrogen phosphate1
Dipotassium hydrogen phosphate1
Sodium citrate2
Bromthymole blue0.08
Sodium chloride5
Agar15
Total24

Preparation

Suspend 24.0g of the medium in 1 litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Sterilise at 121°C for 15 minutes with frequent stirring to completely dissolve the medium. Cool to 45-50°C. Homogenize gently and dispense into appropriate sterile containers.