XLD Agar

XLD Agar is used for the isolation and differentiation of enteric pathogens in a laboratory setting. XLD Agar is not intended for use in the diagnosis of disease or other conditions in humans. Conforms to Harmonized USP/EP/JP Requirements.

XL (Xylose Lysine) Agar Base was developed by Taylor for isolating and differentiating Gram-negative enteric bacilli. XL Agar Base was supplemented with sodium thiosulfate, ferric ammonium citrate, and sodium deoxycholate to develop a more selective medium, XLD Agar.

XLD Agar was developed principally for isolating Shigella spp. and Providencia spp., and shown to be an effective differential media.


Formula Liter
Yeast Extract 3 g
Lactose 7.5 g
Sucrose 7.5 g
Xylose 3.5 g
L-Lysine 5 g
Ferric Ammonium Citrate 0.8 g
Phenol Red 0.08 g
Sodium Chloride 5 g
Sodium Deoxycholate 2.5 g
Sodium Thiosulfate 6.8 g
Agar 13.5 g

Final pH: 7.4 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 55 g of the medium in one liter of purified water.
  2. Heat with frequent agitation until the medium reaches the boiling point.

Order Details

Product # Product Description
7166A XLD Agar, 500 g
7166T XLD Agar, 5 kg