Final answer:
The commercial modification of the disk diffusion test is called the Etest, which is used to determine the Minimum Inhibitory Concentration (MIC) of an antimicrobial drug against a specific microbe.
Step-by-step explanation:
The commercial modification of the disk diffusion test is called the Etest. The Etest is an alternative method used to determine the Minimum Inhibitory Concentration (MIC) of an antimicrobial drug against a specific microbe. It combines the Kirby-Bauer disk diffusion test and dilution methods by using plastic strips with a gradient of the antibacterial drug instead of circular disks.