Integrating static microtiter plate and dynamic flow cell approach for effective in vitro screening of anti- biofilm compounds from Fungi

By Syeda J. Khalid, H. Schrey, M. Müsken,, JP. Wennrich, J.J. Luangsa-ard, S. Ashrafi, W. Maier and M. Stadler

Currently, chronic biofilm-associated infections pose a major challenge in the healthcare sector and effective antimicrobial therapeutics are vital for treatment of such persistent infection. Notable fungal-derived drugs, such
as lefamulin, fingolimod, pleuromutilins, and the recently developed antifungal ibrexafungerp, highlight the significance of fungi in drug discovery. Therefore, this study aims to isolate bioactive fungal metabolites followed by subsequent screening to identify their potential as curative agents for biofilm-associated infections. In vitro techniques used for screening bioactive compounds with potential medicinal value are crucial in research laboratories for testing new compounds. In our setup, while static microtiter plate (MTP) assays facilitate high-throughput screening, we also aim to establish a dynamic flow cell system supporting bacterial growth under flow conditions, more accurately mimicking real in vivo infectious environments. In the course of our ongoing search for novel anti-infectives, we conducted a study to investigate the potential of fungal secondary metabolites for their effects on biofilms. Few compounds showed promising anti-biofilm activity against Staphylococcus aureus in preliminary screening assays prompting an in-depth investigation of their biofilm eradication potential in a model better mimicking real life clinical situation. Therefore, we established a flow cell biofilm system optimized for the robust attachment of S. aureus biofilms, to evaluate the potential of compounds to eradicate mature biofilms. Time-lapse imaging was performed by confocal laser scanning microscopy, providing fine details of the spatial organization of complex biofilm structures4.