| Urea Hydrolysis |
DESCRIPTION
Testing the ability to produce urease, an enzyme that hydrolyse urea providing a source of nitrogen for bacteria.
Testing the ability to produce urease, an enzyme that hydrolyse urea providing a source of nitrogen for bacteria.
NOTES
False positives may result due to protein hydrolysis when incubation is prolonged.
False positives may result due to protein hydrolysis when incubation is prolonged.
REFERENCES:
1. H. Raducanescu, V.Bica-Popii,1986. Bacteriologie veterinara, Ed. Ceres, Bucuresti.
2. Murray, P.R., Baron, E. J., Jorgensen, J.J., Pfaller, M.A., and Yolken, R.H. Manual of Clinical Microbiology, 8th ed.
ASM Press: Washington, DC, 2003.
1. H. Raducanescu, V.Bica-Popii,1986. Bacteriologie veterinara, Ed. Ceres, Bucuresti.
2. Murray, P.R., Baron, E. J., Jorgensen, J.J., Pfaller, M.A., and Yolken, R.H. Manual of Clinical Microbiology, 8th ed.
ASM Press: Washington, DC, 2003.
| Christensen's urea agar positive (left) & negative (right) |
PROCEDURE
Pick a well isolated colony and inoculate medium. Incubate 24 hours at 37 °C.
Reaction is positive if the medium become red (urea is decomposed resulting ammonia which changes the pH).
Pick a well isolated colony and inoculate medium. Incubate 24 hours at 37 °C.
Reaction is positive if the medium become red (urea is decomposed resulting ammonia which changes the pH).
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(c) Costin Stoica
MEDIUM PREPARATION
Composition of Christensen's urea agar medium:
Glucose ........................................................................1g
Peptone ........................................................................1g
KH2PO4 .........................................................................2g
NaCl ..............................................................................5g
Phenol red .............................................................0.012g
Agar ............................................................................20g
H2O ad 1000 ml, pH = 6.8
To base medium add 20 ml urea solution 20% before solidification. Initial
color of the medium must be yellow.
Composition of Christensen's urea agar medium:
Glucose ........................................................................1g
Peptone ........................................................................1g
KH2PO4 .........................................................................2g
NaCl ..............................................................................5g
Phenol red .............................................................0.012g
Agar ............................................................................20g
H2O ad 1000 ml, pH = 6.8
To base medium add 20 ml urea solution 20% before solidification. Initial
color of the medium must be yellow.
MIU medium may also be used for urease testing.
| R E G N U M PROKARYOTAE |
