SIMMONS CITRATE AGAR (as per BIS)

Simmons Citrate Agar is a synthetic test agar proposed by Simmons (1926) for the identification of microorganisms (particularly of enteric Gram-negative bacilli from clinical specimens) on the basis of their metabolism of citrate, being the sole carbohydrate source. The media is used for the differentiation between Enterobacteriaceae and the members of aerogenes group on the basis of citrate utilization as sole carbon source. Initially the citrate medium was developed by Koser containing ammonium salt as the only nitrogen source and citrate as the only carbon source for differentiating Escherichia coli and Enterobacter aerogenes by IMViC tests. Later on Simmons modified Kosers formulation by adding agar and bromothymol blue. It is recommended by APHA. It is also recommended by BIS for isolation of Escherichia coli.

for di?erentiation between faecal coliforms and members of the aerogenes group on the basis of citrate utilization.