A new selective, differential plating medium to screen the common gram-negative urinary tract pathogens is
described. The medium combines adonitol fermentation, phenylalanine deaminase, and P-glucuronidase tests
and allows the indole and cytochrome oxidase tests to be performed directly from the plates. High-level
agreement with individual conventional tests was recorded in comparative studies with 504 cultures of
gram-negative rods. There was 100% agreement, except for the Providencia spp. indole spot test (61.6%
agreement). Adonitol fermentation by Providencia species could not be determined. Escherichia coli, Klebsiella
pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa were identified with a high efficiency (100, 85.7,
83.5, and 100% agreement, respectively) without further testing. There was 96% overall agreement for the 267
infected urine samples tested