Modulating Aspergillus fumigatus biofilm formation: Antifungal-induced alterations in conidium-abiotic surface interactions

Abstract

Biofilm prevention on surfaces supporting microbial growth is an alternative strategy to manipulating microbial cells. This study focuses on Aspergillus fumigatus, a prominent airborne fungal pathogen. We exposed glass, acrylic, high-density polyethylene (HDPE), Nylon 6, polytetrafluoroethylene (PTFE), silicone, and unplasticized polyvinyl chloride (uPVC) surfaces to antifungal agents (triclosan, liposomal amphotericin-B (L-AMB), tyrosol, and farnesol) to study A. fumigatus conidium-abiotic surfaces interactions.

The total protein concentrations of A. fumigatus mycelia were quantified after growth in both a broth medium and on agar, subsequent to treatment with the agents. The hydrophobicity of chosen surfaces and the fungus was assessed using the contact angle and the microbial adhesion to hydrocarbons (MATH) assays, respectively, when subjected to antifungal agents. Moreover, A. fumigatus biofilms on uPVC and PTFE were evaluated through transmission flow-cell culture and optical microscopy.

Hydrophobic surfaces (PTFE and silicone) impregnated with farnesol transformed into hydrophilic. Conversely, L-AMB altered the surface properties of uPVC from hydrophilic to hydrophobic, potentially as a result of L-AMB's interaction with the TiO₂ component in uPVC. Considering the effect of antifungals on conidia, A. fumigatus conidia surfaces exhibited a shift from hydrophobic to hydrophilic characteristics under the influence of these agents.