This is a Provisional monograph.

This selective medium for Legionella spp. was developed by Edelstein in 1982 as a modification of Wadowsky and Yee's (1981) medium. Glycine is added to suppress Gram-negative bacteria, vancomycin and polymyxin B sulfate are added to suppress the growth of Gram-positive bacteria, whilst anisomycin suppresses the growth of yeasts and fungi. Indicator dyes are added to differentiate Legionella species. MWY medium can be used for water samples with a high concentration of background flora.

Prepare and sterilise the basal medium, including the glycine and indicators as for BCYE agar. To the cooled medium (50°C) add fresh filter-sterilised solutions of L-cysteine (0.4 g/10 mL), iron(III) pyrophosphate (0.25 g/10 mL), polymyxin B sulfate (50 000 i.u./10 mL), vancomycin hydrochloride (0.001 g/10 mL) and anisomycin (0.08 g/10 mL).