Thermo Scientific™ Oxoid™ XLT-4 Agar

The Thermo Scientific™ Oxoid™ XLT-4 Agar is a highly selective medium designed for the isolation and identification of Salmonella spp. from clinical, food, and environmental samples. Its advanced formulation, including sodium tetradecylsulfate, enhances selectivity by inhibiting background flora while supporting the optimal growth of salmonellae. This reduces false-positive suspect colonies, saving time and costs in downstream identification.

Key Features

1. Highly Selective:
   • Contains sodium tetradecylsulfate, an anionic surfactant, to inhibit unwanted background flora.
2. Improved Identification:
   • Salmonella colonies appear as black or red colonies with black centers due to thiosulfate reduction to hydrogen sulfide.
3. Reduces False Positives:
   • Minimizes the growth of non-target organisms, simplifying colony differentiation and reducing costs for further identification.
4. Broad Application:
   • Suitable for clinical, food, and environmental testing, ensuring versatility in microbiological workflows.
5. Reliable Differentiation:
   • Differentiation is based on the fermentation of xylose, lactose, and sucrose, as well as the decarboxylation of lysine.

Specifications

Applications

1. Clinical Microbiology:
   • Isolation of Salmonella spp. from fecal samples for diagnostic purposes.
2. Food Safety:
   • Detection of Salmonella in raw, processed, and ready-to-eat food products.
3. Environmental Monitoring:
   • Identifies Salmonella contamination in environmental and production facilities.

Preparation Instructions

1. Suspend 77g of XLT-4 Agar powder in 1 liter of distilled water.
2. Heat gently to dissolve completely.
3. Sterilize by autoclaving at 121°C for 15 minutes.
4. Cool to approximately 50°C, mix well, and pour into sterile Petri dishes.

Colony Characteristics

• Salmonella spp.: Black or red colonies with black centers.
• Escherichia coli: Yellow colonies due to lactose fermentation and pH drop.
• Shigella spp.: Clear red colonies without black centers (do not ferment lactose or reduce thiosulfate).

Advantages

• Highly Selective: Suppresses background flora for clear and reliable isolation of Salmonella spp.
• Cost-Effective: Reduces false positives, saving time and costs in confirmatory testing.
• Comprehensive Differentiation: Supports accurate identification through distinct colony morphologies.
• Versatile Applications: Applicable in clinical, food safety, and environmental microbiology.

Packaging

• Quantity:
  • CM1061B: 500g (for smaller-scale laboratories).
  • CM1061T: 5kg (for large-scale or industrial use).
• Yield: Each 500g prepares approximately 6.5 liters of medium.

Why Choose XLT-4 Agar?

• Optimized for reliable isolation of Salmonella spp. in diverse sample types.
• Ensures efficiency and accuracy with reduced false-positive rates.
• Adheres to industry standards for microbiological testing in food safety and clinical diagnostics.