Definition and Measurement In microbiology, minimuminhibitoryconcentration (MIC) is the lowest concentration of an antimicrobial (like an antifungal, antibiotic or bacteriostatic) drug that will inhibit the visible growth of a microorganism after overnight incubation.
The minimuminhibitoryconcentration of the antibiotic is between the concentrations of the last well in which no bacteria grew and the next lower dose, which allowed bacterial growth.
This is important because populations of bacteria exposed to an insufficient concentration of a particular drug or to a broad-spectrum antibiotic (one designed to inhibit many strains of bacteria) can evolve resistance to these drugs.
MinimumInhibitoryConcentration is the lowest drug concentration that prevents visible microorganism growth after overnight incubation.
Because the concentration of antibiotic that diffuses into the media decreases with increasing distance from the source, a larger zone of inhibition around an antibiotic-containing disk indicates that the bacteria are more sensitive to the antibiotic in the disk.
The size of a zone of inhibition in a KB test is inversely related to the minimuminhibitoryconcentration (MIC), which is the amount of antibiotic required to prevent bacterial growth in an overnight culture.
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