Microbial interactions in biofilms: role of siderophores and iron-dependent mechanisms as biocontrol strategies

Biofilms are ubiquitous in nature and can cause significant problems in public health, medicine and industry. Antimicrobial approaches to treat bacterial proliferation and biofilm formation constitute a focal point of modern research. We are entering a post-chemical antimicrobial era, not only due to the need to delivering of environmentally- friendly products, but also due to the increasing resistance of some pathogens against the most common antimicrobials, and the recalcitrance of biofilms even when treated with high concentrations of chemicals. An innovative approach to control biofilms can be the based on application of the concepts of microbial ecology, already under study in the development of biocontrol on seeds, roots and plants. The modes of action of those biocontrol systems can include, among others, the inhibition of microorganisms by antimicrobial compounds and competition for iron through the production of siderophores. To sequester and solubilise ferric iron, many microorganisms utilise an efficient system consisting of low-molecular mass compounds with high iron affinity termed siderophores (iron-scavenging agents). Siderophore production is a virulence factor of many microorganisms, as they can act as a biocontrol factor. In this review we will present some knowledge on the potential of siderophores and irondependent mechanisms, mainly related with Pseudomonas spp., as a new line of biofilm control strategies.Fundação para a Ciência e a Tecnologia (FCT