The antimicrobial susceptibility test is mainly to realize the tolerance degree of microorganisms to antibacterial agents by determining the minimum inhibitory concentration (MIC) of antibacterial agents against tested microorganisms.

At present, the detection of antimicrobial susceptibility is mainly based on CLSI, EFSA, EUCAST, ISO, WS and other domestic and foreign standards, including the disk diffusion method, broth/agar dilution method and Etest method. Among them, the Etest method comprehensively applies the principles of diffusion method and dilution method, which is setting a continuous and stable antibacterial concentration gradient in advance for the quantitative detection of antibacterial MIC values, to determine the antimicrobial susceptibility of strains used in pharmaceutical, food, feed and other industries.