Oxoid Brilliance Listeria Differential Supplement is added to Brilliance Listeria Agar Base, Mfr
No
CM1080E and Mfr
No
CM1080B, a chromogenic medium for the isolation and differentiation of Listeria Listeria monocytogenes is the most common pathogenic Listeria spp
and has been shown to be pathogenic to both man and animals
Some Listeria ivanovii strains also possess lecithinase activity and, although Listeria ivanovii are primarily pathogenic to animals, there are strains which have been shown to cause infection in humans
Brilliance Listeria Agar uses the chromogen X-glucoside for presumptive identification of Listeria spp
This chromogen is cleaved by β-glucosidase which is common to all Listeria species
Other organisms that possess this enzyme, such as enterococci, are inhibited by the selective agents within the medium; lithium chloride, polymyxin B and nalidixic acid, while amphotericin inhibits the growth of any yeasts and moulds present in the sample
Listeria monocytogenes and pathogenic Listeria ivanovii are then further differentiated by their ability to produce the phospholipase enzyme, lecithinase
This enzyme hydrolyses the lecithin in the medium, producing an opaque white halo around the colony
Brilliance Listeria Agar is a modification of the formulation described by Ottaviani and Agosti
As in the original formulation, the medium is designed to identify Listeria spp
based on their utilization of a chromogenic substrate
However, in this modification, the pathogenic Listeria spp
are then further differentiated by the detection of lecithinase (phosphotidylcholine phospholipase C (PCPLC) activity, rather than phosphotidylinositol phospholipase C (PIPLC) activity
Both enzymes, PCPLC and PIPLC, are associated with virulence in Listeria spp., and, therefore, the presence of either enzyme is a useful indicator of pathogenicity