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 their sole source of nitrogen cause an increase in the alkalinity of the medium resulting in a colour change from green to blue due to the presence of the pH indicator bromothymol blue.

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.

Shelf Life (days): 1095 days

Storage Temp (°C): 10-30°C

Dehydrated Medium Appearance: Fine Powder

Prepared Medium Appearance: Firm Gel

Dehydrated Medium Colour: Yellow

Prepared Medium Colour: Dark Green

Dehydrated PH: 6.9 ± 0.2

Prepared PH: 6.9 ± 0.2

Recommended Incubation: Aerobically at 37°C for 24-48 hours

Formula* g/L

Magnesium Sulphate: 0.2

Ammonium dihydrogen phosphate: 1

Dipotassium hydrogen phosphate: 1

Sodium Citrate: 2

Bromothymol Blue: 0.08

Sodium Chloride: 5

Agar: 15

Total: 24