Selective toxicity, Minimal inhibitory concentration and Minimal lethal concentration

Selective toxicity: Antimicrobial drugs must have selective toxicity. Selective toxicity means the ability of a drug to kill or inhibit the microbial growth with minimal or no damage to the host cell.

Minimal inhibitory concentration (MIC): It is defined as the lowest concentration of an antimicrobial drug that inhibits the visible growth of microbes after overnight incubation. It can be determined by preparing a solution of a drug at increasing concentration and then incubating it with separate batches of cultured microorganism. After incubation, the result is measured either by agar or broth dilution method.

Minimal lethal concentration (MLC): It is defined as the lowest concentration of antimicrobial drug that kills a particular microorganism.