Thermo Scientific™ Oxoid™ Urea Agar Base (Dehydrated), 500G

The Thermo Scientific™ Oxoid Urea Agar Base (Dehydrated) is a high-quality culture medium designed for detecting urease activity in microorganisms, particularly Proteae and some Enterobacteriaceae. When used with a sterile 40% urea solution, it forms Christensen's medium, which is effective for the rapid detection of urease-positive organisms.

Key Features

• Rapid Detection: Detects urease activity in Proteae within 3-5 hours.
• Versatile Applications: Suitable for urease-positive Proteae and other Enterobacteriaceae (requires 24-48 hours for non-rapid urease activity).
• Color Change Indicator: Phenol red in the medium changes from orange to pink when urease-positive organisms hydrolyze urea, producing ammonia.
• Ease of Preparation: Requires the addition of sterile 40% urea solution to the base after autoclaving.

Typical Composition (g/L)

Final pH: 6.8 ± 0.2

Preparation Instructions

1. Suspend 2.4 g of dehydrated medium in 95 mL of distilled water.
2. Bring to a boil to dissolve completely.
3. Autoclave at 115°C for 20 minutes.
4. Cool the medium to 50°C and aseptically add 5 mL of sterile 40% Urea Solution (SR0020).
5. Mix thoroughly and distribute 10 mL into sterile containers.
6. Allow the medium to solidify in the slope position.

Storage and Shelf Life

• Dehydrated Medium: Store at 10-30°C. Use before the expiration date on the label.
• Prepared Medium: Store at 2-8°C. Avoid heating or reheating to prevent urea decomposition.

Appearance

Quality Control

*These control organisms are available as Culti-Loop® strains.

Precautions

1. Ensure the reaction is read within 2-5 hours for Proteae; prolonged incubation may produce false-positive results due to non-urease alkaline reactions.
2. Do not reheat the medium after preparation to avoid urea decomposition.
3. Confirm urease activity by testing with a medium without urea as a control.

Applications

• Urease Detection: Ideal for rapid detection of urease-positive organisms, such as Proteae.
• Differentiation: Useful for identifying non-rapid urease activity in other Enterobacteriaceae.
• Clinical Diagnostics: Supports workflows in diagnostic microbiology for urinary tract pathogens and other urease-positive microbes.

Reference

• Christensen, W. B. (1946). Journal of Bacteriology, 52, 461-466.

The Thermo Scientific™ Oxoid Urea Agar Base is a reliable and versatile tool for microbiological diagnostics, ensuring accurate and rapid identification of urease-positive organisms.