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Piceatannol enhances polymyxin B efficacy against Escherichia coli O157:H7 via inhibition of biofilm formation

Year: 2026

Type: article

Abstract: Introduction Escherichia coli O157:H7 ( E. coli O157 ) poses a severe global health threat, particularly due to its ability to form recalcitrant biofilms and the paradoxical exacerbation of life‑threatening haemolytic uraemic syndrome by conventional antibiotics. This study identifies piceatannol as an effective agent that suppresses E. coli O157 biofilm formation in vitro and acts as an adjuvant to enhance antimicrobial efficacy. Methods The effects of piceatannol on biofilm formation, swarming motility, and exopolysaccharide (EPS) and protein production were evaluated in vitro . Pharmacological screening identified an effective combination with polymyxin B, which was validated in a murine infection model by assessing bacterial loads in visceral organs (liver and spleen), ileal villous morphology, and survival rates. Results Piceatannol suppressed biofilm formation by inhibiting swarming motility and reducing EPS and protein production, thereby weakening biofilm integrity and enhancing antimicrobial efficacy. In vivo , the piceatannol–polymyxin B combination reduced bacterial loads in visceral organs, restored ileal villous morphology, and improved survival more effectively than monotherapy. Discussion These findings establish piceatannol as an effective adjuvant that enhances polymyxin B efficacy against E. coli O157. By disrupting biofilm integrity and sensitizing bacteria to polymyxin B, the piceatannol–polymyxin B combination represents a promising strategy for treating E. coli O157 infections.

Source: Frontiers in Microbiology

DOI: 10.3389/fmicb.2026.1933569