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Xylose lysine deoxycholate agar (XLD agar) is a selective growth medium used in the isolation of Salmonella and Shigella species from clinical samples and from food. [ 1 ] [ 2 ] The agar was developed by Welton Taylor in 1965. [ 3 ]
Bacilli usually have a rod or cylinder shape. Examples include Listeria, Salmonella typhimurium, Yersinia enterocolitica, and Escherichia coli. Yersinia enterocolitica colonies growing on XLD agar plates Escherichia coli Color-enhanced scanning electron micrograph showing Salmonella typhimurium (red) invading cultured human cells
Salmonella spp appear to be yellow or colourless colonies, often with a dark centre. As there are many bacteria that also look like Salmonella on DCA, it is widely recommended that more selective agars are used for the identification of Salmonella, namely xylose lysine deoxycholate (XLD) agar. This growth medium is heat-sensitive and should be ...
Salmonella is a genus of rod-shaped, ... Bacterial colonies may also become trapped in mucus produced in the esophagus. ... XLD agar; References External links ...
Xylose-lysine-deoxycholate agar is used for the culture of stool samples and contains two indicators. It is formulated to inhibit Gram-positive bacteria, while the growth of Gram-negative bacilli is encouraged. The colonies of lactose fermenters appear yellow. It is also used to culture possible Salmonella that may be
XLT Agar (Xylose Lysine Tergitol-4) is a selective culture medium for the isolation and identification of salmonellae from food and environmental samples. It is similar to XLD agar ; however, the agar is supplemented with the surfactant, Tergitol 4 , which causes inhibition of Proteus spp. and other non-Salmonellae. [ 1 ]
Welton Ivan Taylor (November 12, 1919 – November 1, 2012) was an American microbiologist, inventor and civil rights activist.He is known for his work on food-borne pathogens, notably for developing tests for Salmonella and for inventing the XLD (Xylose Lysine Deoxycholate) agar, which can be used to isolate Salmonella and Shigella bacteria.
XLD agar, DCA agar, or Hektoen enteric agar are inoculated; all give colorless colonies as the organism is not a lactose fermenter. Inoculation of a TSI slant shows an alkaline slant and acidic, but with no gas, or H 2 S production. Following incubation on SIM, the culture appears nonmotile with no H 2 S production.