Influence of mutation frequencies providing compensatory plasmid fitness costs in E. coli resistance phenotypes and prevalence of bacterial species in the hospital. The left column shows the influence of different mutation frequencies (10−8, 10−5, and 10−3) compensating plasmid fitness costs in the evolution of E. coli resistance phenotypes. Ec0, susceptible to no resistance plasmids (pink line); EcA, PL1-AbAR (red); EcC, PL3-AbAR-AbCR (light fluorescent green); EcF, AbF*R (violet); EcAC, PL1-AbAR plus PL3-AbAR-AbCR (light blue); EcAF, PL1-AbAR plus AbF*R (brown); EcCF, PL3, AbAR-AbCR plus AbF*R (olive green); EcACF, PL1-AbAR plus PL3-AbAR-AbCR plus AbF*R (dark blue). The right column shows the corresponding effect on the species composition as follows: E. coli (black line), K. pneumoniae (dark olive green), ampicillin-resistant E. faecium (violet), ampicillin-susceptible E. faecium (blue green). Numbers in ordinates are expressed in hecto-cells (one unit = 100 cells in the microbiota). Note the very scarce consequences of the frequency of compensation of plasmid costs on the spread of plasmid-mediated resistant phenotypes.