Some Results on the Use of Crystal Violet in Bacteriological Culture Media for Water Analysis

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Abstract
Salle''s phosphate buffered broth, containing 1 part crystal violet to 700,000 parts water, was tested on 7 laboratory stock strains of the Escherichia-Aero-bacter group, and on 164 Escherichia-type organisms recently isolated from human feces. 43% of these fecal cultures gave negative results after 48 hrs.'' incubation at 37[degree] C; all gave positive results in standard lactose broth. Cultures producing negative results in 48 hrs. eventually produced gas, some requiring as long as 5 days for 10% gas to be produced; the organisms were not killed, but growth was delayed. Results tend definitely toward the conclusion that Salle''s crystal-violet broth should not be adopted as a standard test medium in water analysis. To maintain the proper margin of safety, no medium should be used, which sometimes gives negative results in presence of fecal pollution.