"Phenylethyl alcohol (PEA) agar allows the growth of gram-positive organisms, particularly cocci. It inhibits most gram-negative bacteria and fungi. PEA agar is used to inhibit common contaminants such as Escherichia coli and Proteus species.\n\nTryptic Soy Agar (TSA) allows the growth of gram-positive organisms, particularly cocci. It inhibits most gram-negative bacteria and fungi. PEA agar is used to inhibit common contaminants such as Escherichia coli and Proteus species.\n\nMannitol salt agar or MSA contains a high concentration (about 7.5–10%) of salt (NaCl) which is inhibitory to most bacteria—making MSA selective against most Gram-negative and selective for some Gram-positive bacteria (Staphylococcus, Enterococcus and Micrococcaceae) that tolerate high salt concentrations.\n\nBlood Agar Plate (BAP) tests the ability of an organism to produce hemolysins. The degree of hemolysis by these hemolysins is helpful in differentiating members of the genera Staphylococcus, Streptococcus and Enterococcus.\n\nTable A.1: Biochemical tests and media used to differentiate Enterobacteriaceae"