Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that is resistant to many antibiotics. It is responsible for several chronic infections such as osteomyelitis, endocarditis, or infections of implanted medical devices. These infections are often incurable, even when appropriate antibiotics are used.

Senior author of the study, Prof Kim Lewis of Northeastern University, suspected that a different adaptive function of bacteria might be the true culprit in making these infections so devastating.

The study represents the culmination of more than a decade of research on a specialized class of cells produced by all pathogens called persisters.

“These cells evolved to survive. Survival is their only function. They don’t do anything else,” Prof Lewis said.

Prof Lewis and his colleagues posited that if they could kill these expert survivors, perhaps they could cure chronic infections.

They have found that persisters achieve their singular goal by entering a dormant state that makes them impervious to traditional antibiotics. Since these drugs work by targeting active cellular functions, they are useless against dormant persisters, which aren’t active at all. For this reason, persisters are critical to the success of chronic infections and biofilms, because as soon as a treatment runs its course, their reawakening allows for the infection to establish itself anew.