Coinfection, Competitive-Release and the Evolution of Resistance: A Mathematical Analysis

We adapt the basic susceptible-infected model, to model the emergence of drug resistant pathogens under drug treatment pressure when there is coinfection. We are able to derive the invasion condition R0 for a resistant pathogen under a coinfection framework thereby explicitly linking the emergence of drug resistance to the life history parameters of the pathogen and how they are affected through competition and drug action. This framework allows us to explore analytically the effect of competitive release on the emergence of resistant pathogens. We show that whether or not coinfection and competitive release promotes invasion depends on the relative values of the epidemiological parameters and thus the particular epidemiological cost associated with resistance.