How bacteria fight antibiotics

Researchers report in two separate papers in Science this week on novel methods used by bacteria to avoid being killed by antibiotics. In one study, scientists at the Rockefeller University report that the bacterial cells known as persisters, which tolerate but do not become resistant to antibiotics, preexist in a population and that their random switching between normal and slow-growing persister states enables them to escape antibiotic killing.

And in an accompanying paper, Stanford University researchers demonstrate that certain antibiotics trigger the SOS response in bacteria, resulting in shutdown of DNA replication and transient dormancy, enabling survival of the antibiotic sensitive bacteria. The SOS response prevents damaged DNA from being copied at cell division, said Christine Miller, lead author of the Stanford study. "It's common throughout the whole plant, animal, bacterial world," she said.

Miller and colleagues were investigating conditions that affected the dpiAB gene operon—overexpression of which results in ...