Model of Antibiotic Action on Bacterial Growth
Martin Evans (University of Edinburgh, UK)
In this talk I will describe a simple model for the growth of a bacterial population under the challenge of ribosome-targetting antibiotics. I shall endeavour to motivate why statistical physics lends itself to the study of bacterial dynamics. The model I will discuss is statistical physics-like in that it makes a coarse-grained description of the growth process, reduced to three variables within the bacterial cell – the antibiotic concentration, the concentration of ribosomes bound to antibiotics and the concentration of unbound ribosomes. Remarkably the model can explain several observations concerning antibiotic action and bacterial growth rate. In particular the growth-dependent bacterial susceptibility is controlled by a single, « universal » parameter and the extreme behaviours correspond to the phenomenological classification into bactericidal and bacteriostatic antibiotics. The predictions of the model are backed up by experimental studies.