FIG 4.

MICs and relative fitness of tobramycin, ceftazidime, and ceftazidime-avibactam ALE representative clones in rich laboratory medium, urine, and SCFM. Growth curves of representative clones of tobramycin, ceftazidime and ceftazidime-avibactam ALEs in urine, SCFM, and rich laboratory medium were recorded in rich laboratory medium, urine, and SCFM. The fitness of each strain was measured as the area under the growth curve. The relative fitness of each clone was calculated with respect to the fitness of PA14 wild-type strain in the same medium. The values shown represent the mean from three replicates. For their part, MICs of tobramycin, ceftazidime and ceftazidime-avibactam clones to the antibiotic in which they were selected were also measured in each medium. The relative fitness of each clone with respect to its MIC values is represented.