FIG 7.

The intracellular concentration of fosfomycin does not change in the fosfomycin-resistant mutants. Comparison of the fosfomycin intracellular concentration between the mutants and the parental strain. There is not a deficiency in the fosfomycin transport in the mutants that determines its resistance or a fosfomycin-modifying enzyme involved in this resistance. PA14 and its mutants GlpT and FosA and E. coli K-12 and its mutant UhpT were used as controls of the assay. Error bars indicate standard deviations for the results from three independent replicates. Statistical significance calculated by unpaired two-tail t test: **, P < 0.001; ****, P < 0.0001.