Product number: NCM0100

XLT4 Agar is used with Tergitol 4 for the isolation of non-typhi Salmonella spp and is not intended for use in the diagnosis of disease or other conditions in humans.

XLT4 Agar is a selective differential isolation medium for the specific detection of Salmonella spp. from environmental and food samples. Due to its highly selective nature, XLT4 Agar is particularly effective when used with samples where overgrowth of contaminating flora is expected, for example, fecallycontaminated agricultural samples.

Developed to perform as per Miller & Tate in 1990, this medium was found to improve the recovery of non- typhi Salmonella from chicken and farm environmental samples. Dusch and Altwegg further established the application of XLT4 Agar to salmonellae detection in clinical samples, with the notable exceptions of Salmonella typhi and Salmonella paratyphi. The presence of peptone and yeast extract provides sufficient nutrients to allow the optimal growth of Salmonella spp.

Selectivity is provided by the anionic surfactant Niaproof® 4 (formerly known as Tergitol-4 / sodium tetradecylsulfate). This compound acts as an effective selective agent which is active against Grampositive and many Gram-negative organisms, including Proteus spp.

Differentiation is based on fermentation of the sugars xylose, lactose and sucrose in addition to the decarboxylation of lysine. The inclusion of the pH indicator, phenol red, provides visual evidence of a pH decrease (yellow) or increase (red) in the medium. Ammonium iron (III) citrate is present to distinguish hydrogen-sulfide (H2S) producing from non-H2S producing organisms.

Most enteric organisms, except Shigella, will ferment xylose to produce acid. However, the salmonellae will also decarboxylate the lysine to keep the pH neutral to alkali, thus maintaining red coloration. At nearneutral pH Salmonella can produce H2S from the reduction of ammonium iron (III) citrate and thiosulphate ions producing black or black-centered colonies.

Non H2S-producing salmonellae will be red without a black center.

Other Enterobacteriaceae (non-salmonellae) which are not inhibited by Niaproof-4, will ferment xylose, lactose and/or sucrose but will not decarboxylate lysine. This fermentation activity causes a decrease in pH, resulting in a color change within the colonies from red to yellow.

 

Formula Liter
Proteose Peptone 1.6 g/L
Yeast Extract 3.0 g/L
L-Lysine 5.0 g/L
Xylose 3.75 g/L
Lactose 7.5 g/L
Sucrose 7.5 g/L
Ammonium Iron (III) Citrate 0.08 g/L
Sodium Thiosulfate 6.8 g/L
Sodium Chloride 5.0 g/L
Phenol Red 0.8 g/L
Agar 18.0 g/L

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

Preparation

  1. Suspend 59 grams of the medium in one liter of purified water.
  2. Add 4.6 mL of Niaproof-4 supplement (Sigma Niaproof®, product code N1404).
  3. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  4. DO NOT OVERHEAT OR AUTOCLAVE THIS MEDIUM.
  5. Cool to 45-50°C.

Product was previously known as Acumedia Product: 7517 XLT4 Agar; and LabM Product: LAB221 XLT4 Agar

Order Details

Product # Product Description
NCM0100A XLT4 Agar, 500 g
NCM0100B XLT4 Agar, 5 kg
NCM0100C XLT4 Agar, 10 kg
NCM0100D XLT4 Agar, 25 kg (European only size)
NCM0100E XLT4 Agar, 50 kg (US only size)

Reference Material

NCM0100 - XLT4 Agar, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]
NCM0100 - XLT4 Agar, Technical Specifications Sheet [English]

For additional information or questions about product SDS documents, please contact Neogen at SDS@neogen.com.

Please check with your local representative for availability of these products within your region.