Figure 1. Schematic experimental protocol.

Schematic experimental protocol. Mutants screen and experimental evolution in different doses of Nal (μg/mL) are represented by the colored arrows. Six experimental lines were evolved in each nalidixic acid (Nal) dose from a random selection of resistant mutants (SRef lines). Two lines additional lines per evolution dose (RRef lines) were evolved from a single resistant mutant screened at Nal200 termed RRef strain and also used as the competitor for fitness assays in presence of Nal. Down, the sequenced resistance mutation in the gyrA gene at T_ini as well as at T_fin (only SRef line 4 in Nal 3 changed between T_ini and T_fin).