The search for persisters
The Scientist - 08/11/2015
Embers and a colleague last month (July 27) published a study in Antimicrobial Agents and Chemotherapy, which, along with a separate paper published this May in the same journal, could help explain how some B. burgdorferi might survive antibiotic treatment. Both in vitro studies demonstrated that certain drugs kill most B. burgdorferi, but leave behind a population of persisters—bacteria that are genetically identical to their kin, but become dormant or so slow-growing that they aren’t killed by microbiostatic antibiotics. Kim Lewis, a biochemist at Northeastern University in Boston, who led the May study, noted that persisters differ from antibiotic-resistant bacteria in that they do not have special adaptations that make antibiotics ineffective, they simply survive antibiotic exposure through some other means.
Both Embers and Lewis said they were unsurprised by the presence of these hardy bacteria in increasingly dense cultures of B. burgdorferi. “All bacteria form persisters,” said Lewis. While a 2013 study indicated B. burgdorferi don’t form persisters in vitro, Lewis said the density of bacteria required for such bacteria to emerge wasn’t reached in those experiments.