Wilson Blair Agar w/ BG is recommended for isolation and preliminary identification of Salmonella typhi from clinical specimens. Brilliant green dye inhibits all gram-positive bacteria. Dextrose is the fermentable carbohydrate. Ferrous sulphate is an indicator of H2S production. Bismuth is a heavy metal which is inhibitory to most gram-negative enteric bacilli other than Salmonella. Ferrous sulphate is reduced by Salmonella species in presence of bismuth sulphite and dextrose to form iron sulphide, indicated by black coloured colonies.
1. Murray P. R., Baron J. H., Pfaller M. A., Jorgensen J. H. and Yolken R. H., (Ed.), 2003, Manual of Clinical Microbiology,8th Ed., American Society for Microbiology, Washington, D.C. 2.Wilson W. J. and Blair E. M., 1926, J. Pathol. Bacteriol., 29 : 310. 3.Hajna A. A. and Perry C. A., 1938, J. Lab. Clin. Med., 23:1185.