Antibiotics can sometimes give disease-causing bacteria the ability to kill neighboring bacteria and steal their DNA – a previously unrecognized tactic that can help the microbes resist those drugs.

Drugmakers designing new medications should steer clear of compounds that can trigger this potentially dangerous mechanism, researchers concluded in Friday’s issue of the journal Science.

Scientists have known for decades that the intestinal bacterium E. coli can activate an “SOS response” when attacked by certain drugs. The reaction helps the bacteria scavenge bits of DNA from the environment and integrate that genetic material into their own DNA to help strengthen their defenses against the drugs.

But that response was clearly absent in other bacteria.

The new work, by researchers at University Paul Sabatier in Toulouse, France, sought to determine whether the bacterium Streptococcus pneumoniae might have similar tricks up its sleeve. Strep can cause pneumonia, meningitis, middle ear infections and a host of other ailments.