Thermo Scientific™ Urea-PDA Disk

Description

• Demonstrate urease activity and phenylalanine deamination in Enterobacteriaceae with the reagent-impregnated Thermo Scientific™ Remel™ Urea-PDA Disk
• Urease activity has been shown to differentiate Proteus and Providencia spp
• from other organisms 1,2
• In 1974, Ederer et al
• incorporated urea and phenylalanine into one medium for use as a rapid test 3
• Golden et al
• impregnated filter paper strips with urea and phenylalanine to differentiate members of the Enterobacteriaceae 4
• Henriksen and Closs demonstrated that Proteus strains could be differentiated from other enteric Gram-negative bacilli by their action on phenylalanine 5,6
• In 1950, Henriksen demonstrated that the rapid transformation of phenylalanine into phenylpyruvic acid nearly always coincides with strong urease activity and is practically limited to members of the Proteus group 7
• Easy to use - Rapid test Easy to interpret - Visible color change The Urea-PDA disk contains urea and phenylalanine
• Proteus produces the enzyme urease, which hydrolyzes urea to form ammonia
• Ammonia that is produced causes the phenol red indicator to change from clear to dark pink or red
• Proteus and Providencia spp
• produce a type of amino acid oxidase enzyme, which causes oxidative deamination of phenylalanine yielding phenylpyruvic acid
• When 10% ferric chloride is added to this, it chelates with phenylpyruvic acid to form a green color.