XLT4 Agar Base is an enhancement of the traditional XLD formulation. The Peptone Mixture and Yeast Extract provide nitrogen, vitamins, and minerals. Differentiation is based on the fermentation of Xylose, Lactose, and Sucrose, and the decarboxylation of L-Lysine. Phenol Red acts as the pH indicator. The medium’s superior selectivity is due to the addition of Tergitol 4 (7-ethyl-2-methyl-4-undecanol sulfate), a potent surfactant that significantly inhibits Proteus, Pseudomonas, and other non-Salmonella enteric bacteria. Like XLD, it includes Sodium Thiosulfate and Ferric Ammonium Citrate to detect H₂S production, which results in colonies with black centers.
Advantages
- Enhanced Selectivity: The addition of Tergitol 4 provides a higher degree of inhibition against Gram-positive and non-target Gram-negative bacteria than standard XLD Agar.
- Suppression of Proteus: Effectively prevents the swarming and overgrowth of Proteus species, which is a common challenge in Salmonella isolation.
- High Diagnostic Accuracy: Uses the triple-differentiation system (sugar fermentation, lysine decarboxylation, and H₂S production) to identify pathogens.
- Optimized for Complex Samples: Ideal for environmental monitoring and food safety testing (e.g., poultry and meat) where heavy contamination is expected.
- Clear Visual Identification: Salmonella typically appear as red/pink colonies with black centers, while non-pathogens are yellow or inhibited.
Technical specifications
| Catalogue number |
1159 |
| Brand |
Condalab |
| Application |
Highly selective isolation of non-typhi Salmonella |
| Typical Composition (g/L) |
Peptone Mixture (1.6); Yeast Extract (3.0); L-Lysine (5.0); Xylose (3.75); Lactose (7.5); Sucrose (7.5); Sodium Chloride (5.0); Sodium Thiosulfate (6.8); Ferric Ammonium Citrate (0.8); Phenol Red (0.08); Bacteriological Agar (18.0) |
| Final pH (at 25 °C) |
7.4 ± 0.2 |
| Preparation |
59.02 g/L (+ Tergitol 4) |
| Storage Temperature |
2 – 25 °C |
Available packaging options
| 1159 |
500 g plastic bottle |
