Two simple media for the demonstration of pyocyanin and fluorescin.

Abstract Two simple media for the enhancement of pigment production by certain organisms of the Pseudomonas genus are described. The results of comparative studies employing these media, certain synthetic broths, and some commonly used dehydrated preparations are reported. One hundred (93 per cent) of the 107 strains of Pseudomonas studied were detected by pigment production on medium B; all 107 strains could be detected by the combined use of Heart Infusion agar and 27 per cent on Tryptose agar. The reactions produced strains elaborated a water-soluble pigment; 40 per cent were positive on Difco media A and B. On Difco Proteose peptone No. 3 agar, 77 per cent of the same on the two media by organisms belonging to certain other genera are described.