Persister Development by Borrelia burgdorferi Populations In Vitro

Doxycycline is an antibiotic commonly used to treat Lyme disease and other bacterial infections. The MIC and minimum bactericidal concentration (MBC) forBorrelia burgdorferi have been investigated by different groups but were experimentally established in this study as a function of input cell density. We demonstrated thatB. burgdorferi treated in the stationary phase has a higher probability of regrowth following removal of antibiotic. In addition, we determined experimentally and mathematically that the spirochetes which persist posttreatment do not have a longer lag phase but exhibit a lower growth rate than untreated spirochetes. Finally, we found that treating the spirochetes by pulse-dosing did not eliminate growth or reduce the persister populationin vitro . From these data, we propose thatB. burgdorferi persister development is stochastic and driven by slowed growth.