VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

UREASE PRODUCTION TEST

Principle

• Microorganisms that possess the enzyme urease can hydrolyse urea present in the medium, results in releasing ammonia, Co₂ and water.
• The ammonia reacts in solution to form ammonium carboate ,  resulting in alkalinisation of medium 
• This alkaline reaction is detected by phenol red indicator, which is light orange at pH below 8.1 and becomes pink-red at above pH 8.1.

Methodology

• Streak the surface of urea agar slant with the test organism
• Incubate at 37^ºC for 24 to 48 hours

Result

• Urease positive organisms change the colour of the medium to deep pink

Urease production test

Quality control

• Positive     : Proteus mirabilis
• Negative   : Escherichia coli