A new chromogenic test for the detection of urokinase in the genus Shigella

A simple test for detection of urokinase in Shigella is described. The test is performed by suspending a loopful of bacteria in 100 microliters of a buffered 1mM solution of benzoyl-beta-alanyl glycyl-arginyl-4-nitroanilide acetate (Chromozym U). Enzymatic activity is revealed by formation of a yellow colour after 24 h of incubation at 37 degrees C. The test is able to differentiate serotypes of Shigella dysenteriae, Shigella flexneri, Shigella boydii. The results suggest the possibility of including this chromogenic test in the biochemical assay of Shigella genus.