OXOID XLD Agar

OXOID XLD Agar – High-Performance Selective Medium for Enteric Pathogens

OXOID XLD Agar (Xylose Lysine Deoxycholate Agar) is a premium-quality selective and differential culture medium widely used in microbiology laboratories for the isolation and differentiation of Salmonella and Shigella species from clinical and food samples. Manufactured by Oxoid Ltd, this medium ensures reliable, consistent, and accurate results for diagnostic and research applications.

Key Features of OXOID XLD Agar

• Selective Isolation: Efficiently inhibits Gram-positive organisms while supporting the growth of enteric pathogens.
• Differential Identification: Distinguishes bacteria based on xylose fermentation, lysine decarboxylation, and hydrogen sulfide (H₂S) production.
• High Sensitivity: Ideal for detecting Salmonella spp. and Shigella spp. in mixed cultures.
• Consistent Quality: Produced under strict quality control standards for reproducibility.
• Ready-to-Use Format: Available as dehydrated powder for easy preparation.

Composition of XLD Agar

OXOID XLD Agar contains a carefully balanced formulation, including:

• Xylose
• L-lysine
• Lactose & sucrose
• Sodium deoxycholate (selective agent)
• Phenol red (pH indicator)
• Ferric ammonium citrate & sodium thiosulfate (H₂S indicators)
• Agar base

Principle of XLD Agar

XLD Agar works on three key biochemical reactions:

1. Xylose Fermentation:
   Most enteric bacteria ferment xylose, producing acid and turning the medium yellow.
2. Lysine Decarboxylation:
   Salmonella decarboxylates lysine, reverting the pH to alkaline, resulting in red colonies.
3. Hydrogen Sulfide Production:
   Salmonella spp. produce H₂S, forming black-centered colonies.

Colony Characteristics

• Salmonella spp.: Red colonies with black centers
• Shigella spp.: Red or pink colonies (no black center)
• Coliforms: Yellow colonies due to fermentation

Applications of OXOID XLD Agar

• Clinical microbiology laboratories
• Food safety testing
• Water quality analysis
• Pharmaceutical quality control
• Research and academic laboratories

Advantages

• Accurate differentiation of pathogenic bacteria
• High selectivity reduces contamination
• Trusted brand with global recognition
• Suitable for routine and advanced microbiological testing

Storage and Shelf Life

• Store in a cool, dry place (10–30°C)
• Keep tightly closed to avoid moisture absorption
• Follow manufacturer guidelines for shelf life and preparation

Why Choose OXOID XLD Agar?

With decades of expertise, Oxoid Ltd provides reliable microbiological media trusted by laboratories worldwide. OXOID XLD Agar ensures precision, consistency, and confidence in detecting enteric pathogens.