Comparative Evaluation of Antimicrobial and Antibiofilm Activity of Furfural in a Model Bacterial System

Abstract

The natural compound furfural, obtained from biomass, has been investigated for its antimicrobial properties. However, its comparative antimicrobial, antibiofilm, and antibiotic-modulating activities across different bacterial species have not yet been explored. This research focused on the antimicrobial and antibiofilm effects of furfural against Acinetobacter baylyi, Pseudomonas fluorescens, and Staphylococcus epidermidis . The antibacterial activity of furfural was quantified through a broth microdilution assay, whereas antibiofilm activity was determined using the crystal violet assay. The interaction between furfural and gentamicin was evaluated by checkerboard microdilution. Furfural exhibited concentration-dependent antibacterial and antibiofilm activity across all tested microorganisms. The Minimum inhibitory concentration (MIC) of furfural was 1000 µg/mL for all three bacteria. The Minimum biofilm inhibition concentration (MBIC) was 1000 µg/mL for A. baylyi and P. fluorescens , whereas the MBIC for S. epidermidis was 2500 µg/mL. The MIC of gentamicin was 125 µg/mL against A. baylyi and 62.5 µg/mL against S. epidermidis and P. fluorescens . Combination analysis showed synergy against P. fluorescens (FICI = 0.5), an additive effect against A. baylyi (FICI = 1.0), and S. epidermidis (FICI = 0.75). These findings indicate that furfural exhibits antimicrobial, antibiofilm activities and species-dependent interactions with gentamicin, providing a basis for further evaluation against clinically relevant pathogens.