In the ongoing battle between pathogens and humans, bacteria have an unusual survival tactic: playing dead.
cientists in Boston and elsewhere are increasingly interested in mysterious “persisters’’ — a small number of cells in a bacterial population that are not growing, but are also not dead. They exist in an inactive state that allows them to survive antibiotic treatment, only to awaken later and grow again.
“Persisters are thought to go into deep dormancy. They become zombies of a sort . . . resistant to killing by everything, because they don’t have active targets [for drugs] to attack,’’ said Kim Lewis, director of the Antimicrobial Discovery Center at Northeastern University. “It’s a safety valve for the population.’’
Infectious diseases that are invulnerable to common drugs have become a major public health problem, especially in hospitals, spurring major efforts to combat mutant strains of bacteria that can resist antibiotics. But scientists think persisters probably help bacteria thwart modern medicine as well. They may play a role in recurrent infections — including tuberculosis and urinary tract infections.
Persisters were first reported in 1944, when Dr. Joseph Bigger, a physician from the University of Dublin, used penicillin to kill bacteria, but found survivors that were not antibiotic-resistant. He thought those persister cells might be dormant, but not much attention was given to them over the ensuing decades.