Produkte/Mikrobiologie - LabM/Media Range/M.L.C.B. Agar
M.L.C.B. Agar (Mannitol Lysine Crystal Violet Brilliant Green Agar) LAB 116 Description A medium for the selective isolation of Salmonella spp. (with the exception of S. typhi and S. paratyphi A) from food and faeces. Salmonella colonies are recognised by distinctive colonial appearance and H2S production and like the Bismuth Sulphite Agar of Wilson & Blair, this medium will detect lactose and sucrose fermenting strains. Some problems may occur with H2S negative strains, eg S. pullorum, S. senftenberg, S. sendai and S. berta. This medium should not be used to detect S. typhi and S. paratyphi A, as these strains are more susceptible to the brilliant green dye. Formula | g/litre | Yeast Extract | 5.0 | Tryptone | 5.0 | Meat Peptones | 7.0 | Sodium chloride | 4.0 | Mannitol | 3.0 | L-Lysine HCL | 5.0 | Sodium thiosulphate | 4.0 | Ferric ammonium citrate | 1.0 | Brilliant green | 0.012 | Crystal violet | 0.01 | Agar No. 2 | 15.0 |
Method for reconstitution Weigh 49 grams of powder, disperse in 1 litre of deionised water. Allow to soak for 10 minutes, swirl to mix then bring to the boil with frequent agitation to completely dissolve the powder. Cool to 47˚C and pour plates. DO NOT AUTOCLAVE OR OVERHEAT. Appearance: Pale purple, translucent gel. Minimum Q.C. organisms: Salmonella spp. NCIMB 50076 E. coli (inhibition) NCIMB 50034 |
pH: 6.8 ± 0.2 Storage of Prepared Medium: Plates - up to 7 days at 2-8˚C in the dark. Inoculation: Surface plating, streaking for single colonies. Inoculation can be carried out directly, or from enrichment broths. Because of the low selectivity of this medium the inoculum should not be heavy, and it is recommended that this medium should be used in conjunction with other more selective media. Incubation: 37˚C aerobically for 24 hours.
organism | Growth Characteristics colony size shape & (mm) surface | colour | Salmonella spp. | 2.0-3.0 | CV.E.G. | Black | Salmonella spp. (H2S negative) | 2.0-3.0 | CV.E.G. | Pale | Proteus spp. | 1.0-2.0 | CV.E.G. | Grey brown | Shigella spp. | | | mainly inhibited | Citrobacter spp. | 0.5-2.5 | CV.E.G. | Mainly inhibited pale may have black centre | E. coli | mainly inhibited | | | Klebsiella spp | mainly inhibited | | | Gram positive organisms | mainly inhibited | | |
References Inove et al. 66th meeting of the Japanese Vet. Medicine Society.
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