Akademik Veri Yönetim Sistemi
Molecular Biology Reports, cilt.53, sa.1, 2026 (SCI-Expanded, Scopus)
Background: Multidrug-resistant (MDR) Escherichia coli represents a major global health concern due to its strong biofilm-forming ability, which enhances antimicrobial tolerance and contributes to persistent infections. This study aimed to evaluate the individual and combined antibiofilm and antivirulence activities of lactobionic acid (LBA) and carvacrol (CAR) against clinical E. coli isolates. Methods and results: Fifty-one clinical isolates, including E. coli ATCC 25,922, were assessed for biofilm formation. Antimicrobial activity of LBA and CAR was determined through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Minimum biofilm eradication concentrations (MBEC) were evaluated for 43 strong and moderate biofilm-forming isolates. Synergistic interactions were analyzed using checkerboard assays. RT-qPCR was performed to quantify expression changes in luxS, csgA, pfs, and rpoS, genes associated with quorum sensing, adhesion, and stress response. MIC values for CAR and LBA ranged from 256 to 4096 µg/mL and 2048–16,384 µg/mL, respectively, with MBC/MIC ratios ≤ 4 confirming bactericidal activity. CAR and LBA inhibited biofilm formation by 24.12% and 57.7%, while their combination achieved up to 87.7% inhibition in strong biofilm-forming isolates. Checkerboard assays revealed synergy (FIC ≤ 0.5) in six of seven isolates, resulting in up to 32-fold MIC reductions. RT-qPCR showed significant downregulation of virulence and quorum-sensing genes, with combination treatment producing the strongest effect, including a 10-fold reduction in csgA expression. Conclusions: LBA and CAR effectively inhibit growth, biofilm formation, and virulence in E. coli isolates. These findings support the potential of a carvacrol-lactobionic acid combination as a promising natural treatment for drug-resistant E. coli infections.