TELLURITE GLYCINE AGAR BASE

Description

Bacteria in the genus Staphylococcus are pathogens of man and other mammals. Traditionally they were divided into two groups on the basis of their ability to clot blood plasma (the coagulase reaction). Coagulase-positive strains of Staphylococcus aureus form the most pathogenic staphylococci. The presence of staphylococci in a lesion might first be suspected after examination of a direct gram stain. However, small numbers of bacteria in blood preclude microscopic examination and require culturing first. Tellurite Glycine Agar was originally developed by Ludlam and modified by Zebovitz et al. It is used for the quantitative detection of coagulase-positive staphylococci from foods and other sources like skin, mucous membranes, air and soil etc. This medium supports better growth of coagulase-positive cocci even if present in small numbers. Coagulase positive staphylococci produce black colonies within 24 hours after an incubation at 37?C. Generally other organisms produce no growth during this incubation period with the exception of an occasional coagulase-negative strain that may produce small grey colonies, not readily confused with black coagulase positive colony.