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{{Short description|Selective culture medium}}(File:Salmonella growing on XLD agar.JPG|right|thumb|Salmonella growing on XLD agar)Xylose Lysine Deoxycholate agar (XLD agar) is a (wikt:selective|selective) growth medium used in the isolation of Salmonella and Shigella species from clinical samples and from food.JOURNAL, Zajc-Satler J, Gragas AZ, Xylose lysine deoxycholate agar for the isolation of Salmonella and Shigella from clinical specimens, Zentralbl Bakteriol [Orig A], 237, 2–3, 196–200, 1977, 848209, JOURNAL, Nye KJ, Fallon D, Frodsham D, etal, An evaluation of the performance of XLD, DCA, MLCB, and ABC agars as direct plating media for the isolation of Salmonella enterica from faeces, J. Clin. Pathol., 55, 4, 286–8, April 2002, 11919214, 1769632, 10.1136/jcp.55.4.286, The agar was developed by Welton Taylor in 1965.JOURNAL, Isolation of shigellae. I. Xylose lysine agars; new media for isolation of enteric pathogens, Taylor, Welton I., 5839918, American Journal of Clinical Pathology, 1965, 44, 4, 471–475, 10.1093/ajcp/44.4_ts.471, Other Enterobacteria such as E. coli will ferment the lactose present in the medium to an extent that will prevent pH reversion by decarboxylation and acidify the medium turning it yellow.

• Salmonella species: red colonies, some with black centers. The agar itself will turn red due to the presence of Salmonella type colonies.
• Shigella species: red colonies.
• Coliforms: yellow to orange colonies.
• Pseudomonas aeruginosa: pink, flat, rough colonies. This type of colony can be easily mistaken for Salmonella due to the color similarities.

XLD agar contains:{| class="wikitable"| Yeast extract| 3g/l| L-Lysine| 5g/l| Xylose| 3.75g/l| Lactose| 7.5g/l| Sucrose| 7.5g/l| Sodium deoxycholate| 1g/l| Sodium chloride| 5g/l| Sodium thiosulfate| 6.8g/l| Ferricammoniumcitrate| 0.8g/l| Phenol red| 0.08g/l| Agar | 12.5g/l

See also

• Agar plate
• MRS agar
• R2a agar

References

{{reflist}}

External links

{{Growth media}}{{Microbiology-stub}}