Patent ID: 8377678

Claim:
A growth test medium for the detection of the presence of bacterial viruses in a sample containing bacteria, the test medium comprising: a nutrient growth medium; a gum capable of forming a solid when combined with an additional compound, the forming of the solid is temperature-independent, wherein said additional compound is a divalent metal; a first compound that when cleaved by enzymatic reaction with said bacteria is capable of causing the bacteria to assume a first color and the first color is retained with cellular material of said bacteria after the bacteria are killed by a virus, wherein said first compound is a chromogenic or a fluorogenic enzyme substrate; and a second compound that undergoes chemical reduction when proximate or in contact with living bacteria to form a second color so that areas containing living bacteria assume a third color defined by a combination of the first and second colors, and said areas containing living bacteria are visually distinguishable from areas of non-living bacteria, which are colored only by the first compound, wherein the second compound is a tetrazolium.