Acetate Differential Agar 500G

Acetate Differential Agar is recommended for the differentiation of Shigella species from Escherichia coli based on utilization of acetate. Acetate utilization is indicated by formation of blue colour, due to the utilization of sodium acetate and subsequent formation of an alkaline reaction detected by the presence of bromothymol blue indicator. Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Salmonella Arizonae gives positive reaction. Salmonella Typhi and Shigella sonnei do not utilize acetate hence show negative reaction. Colour of the medium remains green.