描述

Simmons Citrate Agar is used wither as slopes in test tubes or as a plate medium in petri dishes. Positive growth (i.e. citrate utilization) produces an alkaline reaction and changes the colour of the medium from green to bright blue, while in a negative test (i.e. no citrate utilization) the colour of the medium remains unchanged.

Escherichia coli including serotypes from epidemic infantile enteritis, as well as Shigella, Yersinia and Edwardsiella species do not grow on the medium. Serratia and the majority of the Enterobacter, Citrobacter, Klebsiella, Proteus and Providencia species, except Morganella morganii and Klebsiella rhinoscleromatis utilize citrate and produce the characteristic blue coloration4.