A competition model between Pseudomonas fluorescens and pathogens via iron chelation.

In this study we present a competition model between a non-chelator (e.g. pathogen) microorganism and an iron chelator microorganism (e.g. Pseudomonas fluorescens). This latter is a beneficial bacteria that can inhibit the growth of the non-chelator through its iron chelating capability. This phenomena of iron chelation is shown to prevent the pathogen from proliferating to numbers capable of causing disease. A mathematical model is formulated and used to study this competition. The model proposes a new and simple conceptual explanation of interactions. It is a nonlinear system of ordinary differential equations. A qualitative analysis of the model for the batch case (no inflow or outflow from the system) is carried out and the global behavior of the model variables is studied. For the chemostat case, the equilibrium points were derived and their stability was performed through extensive numerical simulations. It is found that iron chelation is able to control the non-chelator microorganism growth under a wide range of conditions. (c) 2009 Elsevier Ltd. All rights reserved.