Final answer:
Tests like the minimum inhibitory concentration (MIC) test, disk diffusion test, and minimum bactericidal concentration (MBC) test determine the efficacy of antimicrobial agents. The MIC measures the lowest concentration preventing visible bacterial growth, while MBC determines the lowest concentration killing 99.9% of the bacteria. The zone of inhibition test is a component of the disk diffusion test and does not by itself measure the efficacy of an antibacterial agent.
Step-by-step explanation:
Determining the Efficacy of Antimicrobial Agents
The efficacy of antimicrobial agents against specific organisms is determined through various tests, including the minimum inhibitory concentration (MIC) test, the disk diffusion test, and the minimum bactericidal concentration (MBC) test. The MIC is the lowest concentration of an antimicrobial that prevents visible growth of a bacterium, while the MBC is the lowest concentration that kills 99.9% of the starting inoculum. These results assist clinicians in choosing the most effective antimicrobial for treatment. In the Kirby-Bauer disk diffusion test, filter paper disks impregnated with antibacterials are placed on agar plates inoculated with the bacteria, creating zones of inhibition which indicate the effectiveness of the drugs against the microbes. All these methods except the zone of inhibition test, which is typically a component of the disk diffusion test, directly measure the efficacy of an antibacterial agent against a particular organism.