Since the first antibiotics reached the pharmacy in the 1940s, researchers discovered that they target various pieces of machinery in bacterial cells, disrupting the bacteria’s ability to build new proteins, DNA, or cell wall. But these effects alone do not cause death, and a complete explanation of what actually kills bacteria after they are exposed to antibiotics has eluded scientists.
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The group found that all bactericidal antibiotics, regardless of their initial targets inside bacteria, caused E. coli to produce unstable chemicals called hydroxyl radicals. These compounds react with proteins, DNA, and lipids inside cells, causing widespread damage and rapid death for the bacteria.
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With the results of these two experiments, the researchers were able to identify three major processes implicated in gentamicin-induced cell death: protein transport, a stress response triggered by abnormal proteins in the cell membrane, and a metabolic stress response.