Urea is a common metabolic waste product of protein digestion in most vertebrates that is toxic to most living organisms. The enzyme Urease catalyzes the breakdown of urea into ammonia & carbon dioxide.
The basic principle of this test is to determine the ability of certain microorganisms to produce the enzyme Urease. It is one of the useful diagnostic tests for identifying bacteria, particularly Proteus spp from other Gram negative bacteria.
Urease test is performed by growing the test organisms on urea agar medium containing the pH indicator, phenol red. During incubation microorganisms capable of producing the enzyme urease will liberate ammonia which cause the rise in pH of the medium. As, the pH increases, the color of the phenol red changes from an orange to deep pink.
In the clinical laboratory, members of the genus Proteus can
be distinguished from other enteric nonlactose-fermenting
bacteria (Salmonella, Shigella) by their fast urease activity. P.mirabilis is a major cause of human urinary tract infections.
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Cited By Kamal Singh Khadka
Assistant Professor in PU, RE-COST, PNC , NA, LA