Loïc's talk

Quantifying the impact of a periodic presence of antimicrobial on resistance evolution in a
homogeneous microbial population of fixed size

Abstract:

Antimicrobial resistance is a major public health issue. The evolution of antimicrobial resistance
often occurs in a variable environment, as antimicrobial is added and removed from a medium or
given periodically to a patient. This environmental variability has a huge impact on the microbes'
fitness landscape, which then switches from a fitness valley to an ascending landscape or vice-versa.

We have investigated the effect of these time-varying patterns of selection within a stochastic
model, focusing on a homogeneous population of fixed size subjected to a periodic alternation of
phases of absence and presence of antimicrobial. Combining analytical approaches and stochastic
simulations, we quantified how the time necessary for fit resistant bacteria to take over the
microbial population depends on the period of the alternations.

Marc's talk: Synthetic networks with cells