In response to customer needs, BD provides multiple media formats to perform similar selective and differential procedures in the microbiology laboratory. Phenylethyl Alcohol Agar with 5% Sheep Blood (PEA) is a selective medium for isolation of gram-positive organisms, particularly gram-positive cocci, from specimens of mixed gram-positive and gram-negative flora. BD BBL™ defibrinated sheep blood is incorporated into the agar as a source of many growth factors while Phenylethyl Alcohol is bacteriostatic for gram- negative bacteria since it selectively and irreversibly inhibits DNA synthesis.