Xylose Lysine Deoxycholate Agar is used for the isolation and differentiation of enteric pathogens. Conforms to Harmonized USP/EP/JP Requirements. XLD Agar is not intended for use in the diagnosis of disease or other conditions in humans.
A medium recommended by the Harmonized Pharmacopeia for isolation and identification of Salmonella from non-sterile products. Conforms to USP/EP/JP performance specification. Originally formulated by Taylor to differentiate enteric pathogens, the agar is widely used as the preferred differential medium for Salmonella spp. The medium is void of peptones but instead uses yeast extract as a carbon, nitrogen and vitamin source and xylose, lactose and sucrose are fermentable carbohydrates. Salmonella are able to ferment xylose to produce acid but not lactose or sucrose. When the xylose is exhausted Salmonella will decarboxylate lysine shifting the pH back to neutral. At near neutral pH, Salmonella can reduce sodium thiosulfate producing hydrogen sulfide which creates a complex with ferric ammonium citrate to produce black or black centered colonies. Other organisms are able to decarboxylate lysine but acid production from the fermentation of lactose and sucrose keeps the pH too acidic for H2S production. Selectivity is achieved through the incorporation of sodium deoxycholate and phenol red acts as a pH indicator. According to the Harmonized Pharmacopeia, Rappaport Vassiliadis Salmonella Enrichment Broth (NCM0103) is used as a selective enrichment broth, with subculture performed onto Xylose Lysine Deoxycholate (XLD) agar.
| Formula | Liter |
| Xylose | 3.5 g/L |
| L-Lysine | 5.0 g/L |
| Lactose Monohydrate | 7.5 g/L |
| Sucrose | 7.5 g/L |
| Sodium Chloride | 5.0 g/L |
| Yeast Extract | 3.0 g/L |
| Phenol Red | 0.08 g/L |
| Agar | 13.5 g/L |
| Sodium Deoxycholate | 2.5 g/L |
| Sodium Thiosulfate | 6.8 g/L |
| Ferric Ammonium Citrate | 0.8 g/L |
pH: 7.4 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.
Preparation
- Suspend 55 grams of the medium in one liter of purified water.
- Heat with frequent agitation and boil for one minute to completely dissolve the medium.
- Autoclave at 121°C for 15 minutes.
- Cool to 45-50°C.
Product was previously known as Acumedia Product: 7166 XLD Agar; and LabM Product: HP008 Xylose Lysine Deoxycholate Agar (USP/EP/JP)
Order Details
| Product # | Product Description |
| NCM0027A | Xylose Lysine Deoxycholate (XLD) Agar, 500 g |
| NCM0027B | Xylose Lysine Deoxycholate (XLD) Agar, 5 kg |
| NCM0027C | Xylose Lysine Deoxycholate (XLD) Agar, 10 kg |
| NCM0027D | Xylose Lysine Deoxycholate (XLD) Agar, 25 kg (European only size) |
| NCM0027E | Xylose Lysine Deoxycholate (XLD) Agar, 50 kg (US only size) |
Reference Material
NCM0027 - Xylose Lysine Deoxycholate (XLD) Agar, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]
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