Cary & Blair Medium Modified PR
Cary & Blair Medium modified with Phenol Red is a semisolid medium employed in the transportation and preservation of clinical specimens such as stools and rectal swabs to prevent the rapid loss of viability of pathogenic enteric Gram-negative bacilli like Shigella, Salmonella spp., Yersinia spp., and Vibrio parahaemolyticus. The medium possesses low nutrient content to prevent replication of unwanted organisms, low red-ox potential to maintain viability of wanted bacilli, and high pH to prevent overgrowth of enteric pathogens like Escherichia coli and Enterobacter spp. Sodium Thyoglycollate is the antioxidant agent. Disodium Phospahte serves as pH buffer. Sodium and Calcium Chlorides supply essential electrolytes and maintain the osmotic balance. Phenol Red is added to demonstrate acidic shifts that might affect the viability of some enteric pathogens.