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Specifications:
| Application | Microbiology | ||
| Storage Temperature | Ambient | ||
| Product Type | Culture Medium | Forms | Powder |
| Product Brand | Liofilchem | ||
| Product Grade | Microbiology grade | ||
Dehydrated Culture Medium for Enterobacteria Differentiation
Liofilchem® Lysine Decarboxylase Broth is a specialized microbiological medium used for the detection and differentiation of Enterobacteria and related organisms based on their ability to decarboxylate lysine. This biochemical reaction aids in the presumptive identification of various Gram-negative bacilli, particularly those in the Enterobacteriaceae family.
Typical Composition (per Liter)
| Component | Concentration (g/L) |
|---|---|
| Peptone | 5.0 |
| Yeast Extract | 3.0 |
| Dextrose | 1.0 |
| L-Lysine | 5.0 |
| Bromocresol Purple | 0.02 |
| Final pH | 6.8 ± 0.2 |
Principle of the Assay
- Nutrient Base: Peptone and yeast extract supply essential nitrogen and growth factors.
- Fermentable Sugar: Dextrose promotes acid production.
- Indicator: Bromocresol purple turns yellow under acidic conditions and reverts to violet in alkaline conditions.
- Decarboxylation Reaction: Organisms with lysine decarboxylase enzyme convert lysine into cadaverine, elevating the pH and turning the medium purple.
Interpretation of Results
| Color | Result | Interpretation |
|---|---|---|
| Yellow | Negative | No lysine decarboxylation |
| Violet | Positive | Lysine decarboxylation occurred |
| Purple (+) | Weak/slow reaction | Incomplete or delayed decarboxylation |
Preparation Instructions
- Suspend 14 g of powder in 1 L of distilled water.
- Mix thoroughly and boil to dissolve.
- Autoclave at 121°C for 15 minutes.
- Overlay inoculated broth with 1 mL of sterile mineral oil.
- Incubate at 35 ± 2°C with caps tightly closed.
Quality Control Organisms
| Microorganism | Growth | Decarboxylation |
|---|---|---|
| Escherichia coli ATCC 25922 | Good | + |
| Salmonella typhi ATCC 6539 | Good | + |
| Salmonella paratyphi ATCC 9150 | Good | – |
| Proteus vulgaris ATCC 13315 | Good | – |
| Salmonella gallinarum ATCC 9240 | Good | + |
| Serratia liquifaciens ATCC 27592 | Good | (+) Slow |
Product Specifications
| Property | Detail |
|---|---|
| Appearance (Dehydrated) | Free-flowing, light beige |
| Appearance (Prepared) | Purple, clear |
| Storage (Powder) | 10–30°C, dry, sealed |
| Storage (Prepared) | 2–8°C |
| Shelf Life | 4 years |
| Packaging Sizes | 100 g, 500 g plastic bottles |
| Catalog Numbers | 610303 (100 g & 500 g) |
Safety & Handling
- Not classified as hazardous.
- For in vitro diagnostic use only.
- Use appropriate PPE (gloves, lab coat, eye protection).
- Dispose of waste per local regulatory guidelines.
Liofilchem® Lysine Decarboxylase Broth is a robust and reliable medium for identifying lysine decarboxylase activity among Enterobacteriaceae. Its selective formulation, visual colorimetric interpretation, and high-quality performance make it an essential tool in diagnostic microbiology, food safety, and environmental monitoring.
- Pack Size: 100g 500g