Rapid identification of micro-organisms from urinary tract infections by beta-glucuronidase, phenylalanine deaminase, cytochrome oxidase and indole tests on isolation media.
Two commercially available media recommended for the isolation and rapid identification of Escherichia coli from urinary tract infections were supplemented with L-phenylalanine and L-tryptophan. The non-selective medium proved suitable for the direct detection of lactose fermentation, beta-glucuronidase and phenylalanine deaminase activities, indole production and the oxidase test. It was highly efficient in making a presumptive identification at species level of the most common gram-negative urinary pathogens, E. coli, Proteus mirabilis and Pseudomonas aeruginosa, that account for c. 85% of all urinary isolates. Among the gram-positive isolates, most colonies were non-fluorescent and could be separated into staphylococci and enterococci on the basis of the catalase test. Fluorescent colonies were found to be Staphylococcus haemolyticus isolates, 61% of which were fluorescent. The selective medium proved suitable for the same biochemical tests, with the exception of indole, which was not visible against the red colour of the medium. Therefore, the differentiation of P. mirabilis from other Proteus-Providencia species was impossible on this medium.
Istituto d'Igiene e Medicina Preventiva, Università di Catania, Italy.
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D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D003470:Culture Media; D003576:Electron Transport Complex IV / Q000378:metabolism; D005456:Fluorescent Dyes; D005966:Glucuronidase / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000302:isolation & purification* / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000302:isolation & purification; D006801:Humans; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D012680:Sensitivity and Specificity; D014552:Urinary Tract Infections / Q000382:microbiology*
D003470:Culture Media; D005456:Fluorescent Dyes; D007211:Indoles; D006923:Hymecromone; C034888:4-methylumbelliferyl glucuronide; C030374:indole; D000594:Amino Acid Oxidoreductases; C022342:phenylalanine oxidase; D003576:Electron Transport Complex IV; D005966:Glucuronidase