Molecular mechanism of gallium nitrate in inhibiting bacterial biofilm formation through pykF modulation

In the context of bacterial regulation, gallium nitrate—a non-redox analog of iron(III)—inhibits bacterial biofilms and virulence. This study aims to elucidate the potential mechanisms and modes of action through which gallium nitrate regulates bacterial activity and function.
We investigated the antimicrobial properties of gallium nitrate, its impact on bacterial biofilms, and gallium-related bacterial signaling pathways. Following the observation that the antibiofilm activity of gallium nitrate significantly upregulated the expression of pyruvate kinase (the pykF gene), we performed in vitro and in vivo studies to explore how gallium regulates the expression, activity, and function of bacterial pykF.
Crystal violet staining, XTT assay, confocal laser scanning microscopy, and scanning electron microscopy confirmed that gallium nitrate effectively inhibited bacterial biofilm formation and activity. Subsequent transcriptomic sequencing and validation screening identified a potential close association between pykF and gallium nitrate-mediated bacterial inhibition. Finally, both in vitro and in vivo experiments demonstrated that pykF knockout significantly increased bacterial viability as well as biofilm formation ability.
We demonstrated that gallium nitrate regulates bacterial biofilm formation and virulence. Furthermore, its antimicrobial activity was attributed to the upregulation of pykF. Therefore, simultaneous intervention targeting both pykF and gallium may offer a more effective therapeutic strategy against recalcitrant bacterial infections caused by biofilms. Our findings also provide a novel rationale for clinically reducing biofilm formation and mitigating device-associated infections.