Liofilchem® Urea Rapid Test Kit, 30 Tests

The Urea Rapid Test by Liofilchem is a diagnostic tool designed for rapid detection of urease activity in bacterial isolates. The test is particularly useful for distinguishing Proteus, Klebsiella, and certain urease-positive yeasts from urease-negative organisms like Salmonella spp.. This test serves as an aid in diagnostic workflows, requiring further confirmatory tests to complete the identification process. Its easy-to-use design and rapid results make it ideal for microbiological laboratories.

Key Features

1. Rapid Urease Detection:
   • Designed to quickly detect the production of urease enzyme by certain bacteria and yeasts.
   • Utilizes a color change in the phenol red indicator to confirm the presence of urease activity.
2. Broad Applicability:
   • Used for differentiating Salmonella spp. (urease-negative) from urease-positive organisms like Proteus and Klebsiella.
   • Effective for testing clinical and non-clinical bacterial isolates.
3. Convenient Kit Format:
   • Contains 30 individual test tubes pre-filled with desiccated reagents, allowing multiple tests per kit.
4. Rapid Results:
   • Positive urease activity is indicated by a color change to red-fuchsia, often visible within 1–4 hours of incubation.
   • Complete results are available within 24 hours.

Composition

Each test tube contains:

• Proteic Substrata: Provides nutrients for bacterial growth.
• Urea: The target substrate for urease activity.
• Phenol Red: pH indicator that changes color in response to urease-induced alkalinization.

How It Works

1. Enzymatic Reaction:
   • Urease hydrolyzes urea into ammonia, water, and carbon dioxide.
   • The release of ammonia increases the pH of the medium, causing the phenol red indicator to change color from yellow to red-fuchsia.

Test Procedure

1. Preparation:
   • Allow the required number of test tubes to reach room temperature.
   • Add 0.3 mL of sterile physiological solution (0.85% saline) to each tube.
2. Inoculation:
   • Use a fresh overnight culture to prepare a microbial suspension equivalent to 0.5 McFarland turbidity standard (1–2 x 10⁸ CFU/mL for E. coli).
   • Inoculate the suspension into the test tube.
3. Incubation:
   • Incubate the tubes at 35 ± 2°C.
   • Observe for color changes at 1 hour, 4 hours, and up to 24 hours.
4. Interpretation:
   • Positive Result: Medium turns red-fuchsia (urease-positive organisms like Proteus mirabilis).
   • Negative Result: No color change; the medium remains yellow (urease-negative organisms like E. coli).

Applications

• Identification of urease-positive bacteria in clinical microbiology, such as Proteus, Klebsiella, and certain yeasts.
• Differentiation of Salmonella spp. (urease-negative) from urease-positive organisms.
• Use in environmental and food microbiology for bacterial differentiation.

Quality Control

1. Appearance:
   • Dry powder: Yellowish.
   • Reconstituted solution: Yellow.
2. Control Strains:
   • Escherichia coli (ATCC® 25922): Negative reaction (no color change).
   • Proteus mirabilis (ATCC® 29906): Positive reaction (color change to red-fuchsia).
   • Salmonella Typhimurium (ATCC® 14028): Negative reaction (no color change).

Storage and Stability

• Temperature: Store at 2–8°C in its original packaging.
• Shelf Life: 1 year. Do not use beyond the expiry date or if signs of deterioration are observed.

Precautions

1. For Professional Use Only:
   • Designed for laboratory settings and must be handled by trained personnel.
2. Safety:
   • Follow aseptic techniques to prevent contamination.
   • Dispose of used materials as per local and national regulations.
3. False Positives:
   • Prolonged incubation may result in false positives due to protein hydrolysis in the medium.
4. Cross-contamination:
   • Avoid by using disposable inoculation tools and ensuring sterility during testing.

Limitations

• False-negative results may occur with strains that grow poorly on the medium.
• Pigmented organisms may yield ambiguous results.
• Additional confirmatory tests are required for final identification.

Product Packaging

• Kit contains 30 test tubes, each pre-filled with reagents.

References

1. Christensen, W.B. (1946). "Urea hydrolysis in the differentiation of bacteria." Journal of Bacteriology.
2. Public Health England (2019). "Urease test." UK Standards for Microbiology Investigations.

Order Information

• Catalog Number: 88011
• Packaging: 30 tests per kit

For more details, refer to the technical documentation and quality standards for microbiological testing.