This medium was introduced by Taylor in 1965 to imp
rove the recovery and recognition of
spp, and has proved to be an excellent
spp. The medium is low in nutrients and relies on a
small amount of sodium desoxycholate for selectivi
indicator system is novel and complex. Most enteric
will ferment xylose to produce acid. However the
salmonellae will also decarboxylate the lysine to k
eep the pH neutral. At near neutral pH
can produce H
S from the reduction
of thiosulphate producing black or black centred co
spp. can also decarboxylate lysine, however, the ac
id produced by
fermentation of both lactose and sucrose will keep
the pH too acid for H
S to be produced.
Ferric ammonium citrate
Method for reconstitution
Weigh 53.5 grams of powder, disperse in 1 litre of
deionised water. Allow to soak for 10 minutes, swir
l to mix. Bring rapidly to the boil
with frequent stirring, and transfer immediately to
a 47°C water bath. Pour into plates as soon as the
medium has cooled. Protracted boiling
or prolonged holding at elevated temperature induce
Light rose, clear gel.
7.4 ± 0.2
Minimum Q.C. organisms:
.typhimurium WDCM 00031
(inhibition) WDCM 00013
Storage of Prepared Medium:
Plates – up to 7 days at 2-8°C in the dark.
Surface, streaking out for single colonies.
37°C for 18-24 hours aerobically.
Trans. black centre
of acid ppt
inhibited (ppt around
Trans. Pink (black
Taylor, W.I. (1965). Isolation of shigellae. I. Xyl
ose Lysine Agars: New media for the isolation of en
teric pathogens. Am. J. Clin. Pathol., 44: 471-475.
Taylor, W.I., and Harris, B. (1965). Isolation of s
higellae. II. Comparison of plating media and enric
hment broths. Am. J. Clin. Pathol., 44(4), 476-479.
Taylor, W.I., and Harris, B. (1967). Isolation of s
higellae. III. Comparison of new and traditional me
dia with stool specimens. Am. J. Clin. Pathol., 48:
Taylor, W.I., and Schelhart, D. (1967). Isolation o
f shigellae. IV. Comparison of plating media with s
tools. Am. J. Clin. Pathol., 48: 356-362.