BAIRD PARKER AGAR W/O EGG YOLK EMULSION

Baird Parker Agar was developed by Baird Parker from the Tellurite-glycine formulation of Zebovitz et al for isolation and enumeration of Staphylococci in food and other material since it allows a good differentiation of coagulase positive strains. A high correlation has been found between the coagulase test and the presence of clear zone of lipolysis in this medium, which is due to the lecithinase of Staphylococci that breakdown, the egg yolk. The limitation of the medium is inadequacy of the egg yolk clearing activity to differentiate S. aureus from other contaminant bacteria. Baird Parker Agar without the addition of Egg Yolk Emulsion for isolation of Staphylococci from food samples was found to be less inhibitory to Staphylococcus aureus than other media at the same time being more selective. This medium successfully replaces Egg yolk emulsion with Tween 80 and Magnesium chloride. The efficacy of the medium was compared with Baird Parker Agar Base, and the results were found to be comparable.
Alternatively, the medium can also be tested using Fibrinogen Plasma Trypsin Inhibitor supplement. On this medium, coagulase positive colonies appear white to grey-black surrounded by an opaque zone due to coagulase activity within 24-48 hours of incubation at 35?C. Reduction in tellurite is necessary because of absence of egg yolk emulsion. This results in translucent agar and white to grey coloured colonies of Staphylococci.

recommended for direct enumeration of coagulase positive Staphylococci