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Why does unnecessary antibiotic use contribute to drug-resistant organisms?

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A lab technician wearing protective gloves and face shield lifts a rack of deep-frozen cells from a cryopreservation tank emitting vapor in a laboratory setting. — pharmaceutical industry A technician withdrawing deep-frozen cells for in vitro culture at a laboratory of a German pharmaceutical company.

Unnecessary antibiotic use contributes to the development of drug-resistant organisms through the process of natural selection. In any bacterial population, spontaneous mutations may occur that provide certain individuals with a survival advantage against a specific antibiotic.1234

When antibiotics are used indiscriminately—such as when they are prescribed for viral infections, taken in incomplete courses, or used for growth promotion in livestock—they eliminate the vulnerable, non-resistant bacteria. With their competitors removed, the resistant strains are left to survive, multiply, and proliferate. Furthermore, these resistant bacteria can transfer their resistance genes to other organisms through processes like gene exchange or transduction.41235

This widespread and inexact use of antibiotics is a significant public health concern, as it accelerates the evolution of resistant strains, rendering infections increasingly difficult or impossible to treat with standard medical therapies. Ethical medical practice necessitates the responsible use of these life-saving drugs to preserve their efficacy for future generations.461