In microbiology, the minimum inhibitory concentration (MIC) is the lowest concentration of a chemical that prevents visible growth of a bacterium (in other words, at which it has bacteriostatic activity), whereas the minimum bactericidal concentration (MBC) is the concentration that results in microbial death (In other words, the concentration at which it is bactericidal).
The MIC of a chemical is determined by preparing solutions of the chemical at increasing concentrations, incubating the solutions with the separate batches of cultured bacteria, and measuring the results using agar dilution or broth microdilution, usually following the guidelines of a reference body such as the CLSI, BSAC or EUCAST (European Committee on Antimicrobial Susceptibility Testing).. A commercial system to test the MIC is the Etest
In medicine, culturing the organism infecting a patient with available antibiotic drugs and determining the MICs, is important for identifying the correct drug to actually give to the patient.
The first step in drug discovery programs is often the screening of a library drug candidates for MICs against bacteria of interest. As such, MICs are usually the starting point for larger preclinical evaluations of novel antimicrobial agents.