Fig. 5.

The Mycobacterium tuberculosis genetic background modulates the fitness effect of fluoroquinolone-resistance mutations. (A) Fitness of ofloxacin-resistant Mtb strain with specified gyrA mutation relative to the fitness of their respective wild-type ancestral strain. Fitness was measured by cell growth assay in antibiotic-free conditions. Ancestral strain per gyrA mutant is indicated in the gray bar above each panel. (B) Association between the relative fitness of specified gyrA mutant and their absolute frequency after the fluctuation analysis performed in figure 1A and as reported in figure 3A, in three genetic backgrounds (N0157, N1283, and N0145).