Gelatin Mannitol Salt Agar (Staphylococcus Agar No. 110)

Gelatin Mannitol Salt Agar (Staphylococcus Agar No. 110) is recommended for selective isolation and differentiation of pathogenic Staphylococci. This medium is recommended by APHA and AOAC for the selective isolation of pathogenic Staphylococci on the basis of pigment production, mannitol fermentation and gelatin liquefaction. The medium can be used with Egg Yolk Emulsion (FD045) to study the egg yolk reactions. Mannitol fermentation can be visualized as yellow colouration by addition of a few drops of bromothymol blue to the areas of the plates where colonies have been removed. Gelatin liquefaction can be seen when the plates are flooded with a saturated aqueous solution of ammonium sulphate. On incubation at 35-37°C for 10 minutes, clear zone are observed. Enterococcus faecalis may grow on this medium as small colonies with slight mannitol fermentation