Development of an implantable three?dimensional model of a functional pathogenic multispecies biofilm to study infected wounds

Abstract

Chronic wounds cannot heal due to impairment of regeneration, mainly caused by the persistentinfection of multispecies biofilms. Still, the effects of biofilm wound infection and its interaction withthe host are not fully described. We aimed to study functional biofilms in physiological conditionsin vitro, and their potential effects in health and regeneration in vivo. Therefore, Pseudomonasaeruginosa, Staphylococcus aureus and Enterococcus faecalis were seeded in collagen?based scaffoldsfor dermal regeneration. After 24 h, scaffolds had bacterial loads depending on the initial inoculum,containing viable biofilms with antibiotic tolerance. Afterwards, scaffolds were implanted onto fullskin wounds in mice, together with daily supervision and antibiotic treatment. Although all micesurvived their health was affected, displaying fever and weight loss. After ten days, histomorphologyof scaffolds showed high heterogeneity in samples and within groups. Wounds were strongly,mildly, or not infected according to colony forming units, and P. aeruginosa had higher identificationfrequency. Biofilm infection induced leucocyte infiltration and elevated interferon?? and interleukin?10in scaffolds, increase of size and weight of spleen and high systemic pro?calcitonin concentrations.his functional and implantable 3D biofilm model allows to study host response during infection, providing a useful tool for infected wounds therapy development.