Resist or perish: Fate of a microbial population subjected to a periodic presence of antimicrobial
Fig 1
Periodic presence of a perfect biostatic antimicrobial.
A: Microbial fitness versus genotype with and without antimicrobial. Genotypes are the following: S: sensitive; R: resistant; C: resistant-compensated. δ represents the fitness cost of resistance. B: Periodic presence of antimicrobial (gray: presence, white: absence), and impact on the fitness of S microorganisms. C: Probability p0 that the microbial population goes extinct before resistance gets established versus alternation period T, for various carrying capacities K. Markers: simulation results, with probabilities estimated over 102 − 103 realizations. Horizontal solid lines: analytical predictions from Eq 1. Dashed lines: T/2 = τS. D and E: Numbers of S, R and C microorganisms versus time in example simulation runs for K = 1000, with T = 20 and T = 1000 respectively. In D, resistance takes over, while in E, extinction occurs shortly after antimicrobial is first added. Phases without (resp. with) antimicrobial are shaded in white (resp. gray). Parameter values: fS = 1 without antimicrobial, with antimicrobial, fR = 0.9, fC = 1, gS = gR = gC = 0.1, μ1 = 10−5 and μ2 = 10−3. All simulations start with 10 S microorganisms.