Figure 2

Emergence of double resistance as a function of the effect of stress on mutation. The double resistance emergence for each strategy is plotted, in log scale, as a function of $\frac{{\mu }_s}{{\mu }_r}$, which varies from 1 to 50. Note that lower emergence values indicate higher efficiency of the strategies. Mixing is plotted in green, cycling in blue, and combining in red. Double resistance emergence is monotonically increasing in σ (persistence of antibiotic resistance), so curves with intermediate values of σ will be within the boundaries of the curves σ = 0 and σ = 1 displayed. The value of σ is irrelevant for combining, so only one curve is produced. An intersection of the curves implies that the preference between two strategies, with respect to the emergence of double resistance, should change. We can see that for a wide range of $\frac{{\mu }_s}{{\mu }_r}$, cycling is the most efficient strategy. When σ is low enough, cycling is the most efficient strategy even without SIM. The emergence is taken over 600 days. The length of each cycle in the cycling strategy is 200 days. Other parameter values: β = 0.9, γ = 0.03, m = 0.1, λ _s = 0.1, ${\lambda }_{R_1}=0.1$, ${\lambda }_{R_2}=0.1$, τ = 0.5. SIM, stressed-induced mutation.