Harlequin® Listeria Chromogenic Agar was developed to isolate and differentiate L. monocytogenes and other Listeria spp. Listeria spp. are differentiated based on β-glucosidase enzyme activity and L. monocytogenes is differentiated based on its phospholipase enzyme activity. Lithium chloride in the base medium and supplementary antimicrobial compounds Ceftazidime, Polymyxin, Nalidixic acid and Cycloheximide provide the medium’s selectivity.
Typical Formulation | g/Liter |
Meat peptone | 18 g |
Tryptone | 6 g |
Yeast extract | 10 g |
Lithium chloride | 10 g |
Sodium chloride | 5 g |
Disodium hydrogen orthophosphate anhydrous | 2.5 g |
Sodium pyruvate | 2 g |
Glucose | 2 g |
Glycerophosphate | 1 g |
Magnesium solphate | 0.5 g |
5-bromo-4-chloro-3-indolyl-β-D-glucopyranoside | 0.05 g |
Agar | 13.5 g |
Grams per liter | 70.5 g |
Final pH: 7.2 ± 0.2