Fig 2.

Time-dependent killing of L. monocytogenes treated with 100 μg of norfloxacin ml⁻¹. (A) L. monocytogenes EGDe (■) in BHI (full line) or peptone saline (broken line). Experiments were performed with three and two biological replicates, respectively, and error bars indicate the standard deviations. (B) Killing of surviving persisters from panel A. Two persister isolates, B1 (◆) and B2 (▲), which survived 24 h of treatment with 100 μg of norfloxacin ml⁻¹ in BHI, were exposed to a second 24-h treatment with 100 μg of norfloxacin ml⁻¹ in BHI. One persister isolate, B3 (●), which survived the second cycle (B1) of 24 h of treatment with 100 μg of norfloxacin ml⁻¹ in BHI, was exposed to a third 24-h treatment with 100 μg of norfloxacin ml⁻¹. As a control, a nonpersister EGDe (■) was included. The experiment was performed once.