A selective and/or differential agar culture medium intended to be used for the growth and differentiation of coliform bacteria and Enterobacteriaceae from a clinical specimen using lactose and/or sucrose fermentation. It typically consists of formulations containing dye compounds [e.g., eosin methylene blue (EMB), fuchsin sulphite (Endo), crystal violet and bromothymol blue (Drigalski)] which inhibit growth of gram positive bacteria and result in coloration of the agar and/or colonies.