Abstract

Bacteriophages (phages) are increasingly applied to control Listeria monocytogenes , a major foodborne pathogen, but their effectiveness is often limited by phage-resistant regrowth. Therefore, strategies that suppress phage-resistant strains are needed to improve phage-based applications. Here, we evaluated a combined antibacterial strategy using pyrogallol, a naturally occurring polyphenol, with a newly isolated Listeria phage, vB_Lmo_SI38 (SI38), to enhance lytic efficacy and suppress resistance development. Phage SI38 lysed 52.4% (32/61) of clinical and food-derived isolates and exhibited serotype-specific activity toward serotype 4b strains. Genome analysis revealed a 39,477-bp double-stranded DNA genome encoding 65 predicted open reading frames without known virulence factors or tRNAs, and the phage was classified within class Caudoviricetes. Structural prediction of receptor-binding proteins supported the observed serotype specificity. Although SI38 alone rapidly reduced bacterial populations, resistant subpopulations emerged and caused regrowth. In contrast, combining SI38 (multiplicity of infection 100) with pyrogallol (16 μg/mL; 0.25× minimum inhibitory concentration) reduced resistant cells to below detectable levels within 48 h and prevented regrowth. Experimental analyses revealed increased reactive oxygen species accumulation, altered oxidative stress-related gene expression, membrane permeabilization, and severe cellular damage. These findings demonstrate that phage–polyphenol synergy enhances phage-based biocontrol and mitigates resistance-driven regrowth, providing mechanistic insight for future food-relevant applications.