Selection of Resistant Bacteria at Very Low Antibiotic Concentrations
Figure 6
Fixation time for adaptive mutations.
(A) 50% penetration time as function of selection coefficient when no mutants are present initially for N = 107 and, from top to bottom, u = 10−9, 10−8, 10−7, and 10−6. Red lines are from Eq. (4) and the crosses from the stochastic model, Eqs. (7) – (10), with m0 = 0. (B). 50% penetration time as function of the selection coefficient when the initial presence of mutants is determined by mutation-selection balance, m0 = Nf0 = uN/|s0|. Results are for s0 = −0.02, N = 107 and, from top to bottom, u = 10−6, 10−7, 10−8. The red lines are from Eq. (6), and the crosses are from the stochastic model, Eqs. (7) – (10).