Totally synthetic medium for susceptibility testing.

The results of disk diffusion and plate dilution susceptibility testing of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis on media gelled with agar-agar or with a synthetic hydrogel were compared. Synthetic hydrogel can be combined with a totally defined synthetic amino acid medium to yield a reproducible, totally defined, synthetic solid medium without the antagonistic or booster effects of some components of agar. Such a medium could be used as a reference medium for susceptibility testing.