Human-like Biofilm Models to Study the Activity of Antifungals Against Aspergillus fumigatus.

Aspergillus fumigatus is an opportunistic filamentous fungus that primarily affects the respiratory tract of the human body. Depending on its host's immune response, the pathogen can cause invasive pulmonary aspergillosis (IPA). Biofilm formation by A. fumigatus increases virulence and resistance against antifungals and immune response and is one important factor in IPA development. Here, two human-like models, precision cut lung slices (PCLS) and a biofilm co-culture model, have been developed to test the anti-biofilm activity of voriconazole, amphotericin B, as well as luliconazole against A. fumigatus. In both assays, metabolically active A. fumigatus biofilms were examined at different biofilm developmental stages using an XTT assay. A decrease in the metabolic activity of the fungal biofilms was detected for each of the tested agents in both assays. Significant anti-biofilm effects exist against early-stage biofilm in the co-culture model. In the PCLS assay, amphotericin B showed the strongest inhibition after 24 h. In conclusion, the applied PCLS ex vivo model can be used to study the property and activity of certain antifungal compounds against Aspergillus biofilm. With its close resemblance to human conditions, the PCLS model has the potential for improving the current understanding of biofilm treatments in laboratory settings.