Theoretical investigation of stochastic clearance of bacteria

Understanding mechanisms of bacterial eradication is critically important for overcoming the failures of antibiotic treatments. Current studies suggest that the clearance of large bacterial populations proceeds deterministically, while for smaller populations the stochastic effects become more relevant. We developed a theoretical approach to investigate the bacterial population dynamics under the effect of antibiotic drugs using a method of first-passage processes. It allows us to explicitly evaluate the most relevant characteristics of the bacterial clearance dynamics such as extinction probabilities and extinction times. In addition, we investigate the effect of fluctuations in the population growth rates on dynamics of bacterial eradication. It is found that fluctuations for some range of parameters increase the extinction probability and the extinction times, indicating slowing the bacterial clearance. We speculate that this might be a first step in developing of antibiotic resistance.