Cloak and Dagger

A new study published in Nature Chemical Biology shows that bacteria can "go undercover" to avoid antibiotics — not by mutating, but by disguising themselves, says 80beats' Veronique Greenwood. When antibiotics are administered, they activate a stress response in bacteria that unleashes a toxin. This toxin, normally kept in check by the bacterium when there is no stress response, shreds its mRNA and causes the cell to go into "lockdown," Greenwood says. Since the cell is technically dead at this point, the antibiotic passes over the bacterium, and once the drug is gone and the bacterium's stress response has subsided, the toxin levels go down, and the bacterium is once again able to build new proteins. "Toxin-antidote pairs have always been something of an enigma for biologists. Why, they wonder, would bacteria go around carrying the cellular equivalent of a loaded gun?" Greenwood says. "This study provides one possible answer: the gun lets them fake their death when the going gets tough." Knowing the different strategies bacteria use to avoid antibiotics, researchers can build better drugs, she adds.