Fig. 2.

Parameter space for coexistence in a two-allele two-locus model of resistance. One locus determines resistance ($s$ or $r$), and the other determines duration of carriage ($A$ or $B$). The coexistence space is constrained by the lines $\tau \ge {\mu }_A(c_{\beta }{c}_{\mu }-1)$ and $\tau \le {\mu }_B(c_{\beta }{c}_{\mu }-\mathrm{\hspace{0.17em}1})$, with ${\mu }_A<{\mu }_B$, where $\tau$ is the antibiotic consumption rate, $\mu$ is a strain’s clearance rate, $c_{\beta }$ is the cost of resistance in transmission, and $c_{\mu }$ is the cost of resistance in clearance. In this plot, ${\mu }_A=0.5,{\mu }_B=1,c_{\beta }{c}_{\mu }=1.1$. We use cost to mean proportional multiplicative cost: $c=1$ corresponds to no cost.