Transcriptomic insights into the synergistic bactericidal mechanisms of the simultaneous treatment of ultrasound and ultraviolet on <em>Escherichia coli</em> O157:H7

This study analyzed the differentially expressed genes (DEGs) of <em>Escherichia coli</em> O157:H7 after combined ultrasound and ultraviolet (US+UV) treatment to explore molecular inactivation mechanisms. A total of 2,133 genes showed differential expression, including 1,055 up-regulated and 1,078 down-regulated genes, indicating pronounced transcriptomic changes. Functional enrichment analyses based on Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases demonstrated that these DEGs were mainly associated with pathways related to carbohydrate metabolism and transport, the tricarboxylic acid (TCA) cycle, amino acid synthesis, oxidative phosphorylation, and quorum sensing. Notably, TCA cycle-related genes (<em>frdD</em>, <em>frdB</em>) were significantly up-regulated, which likely enhanced electron flow into the oxidative phosphorylation pathway, thereby promoting ATP synthesis and energy production to counteract stress-induced damage. Conversely, genes related to ABC transporters (e.g.,<em> fepB</em>, <em>malK</em>) and ribosomal proteins (e.g., <em>rplK</em>, <em>rpsF</em>) were markedly down-regulated, indicating that disrupted membrane transport and protein synthesis under stress conditions. Furthermore, the up-regulation of quorum sensing genes (e.g., <em>lsrC</em>, <em>lsrK</em>) indicated enhanced intercellular communication, possibly linked to stress adaptation. Overall, US+UV treatment exerted a profound impact on multiple metabolic and regulatory pathways, leading to cellular dysfunction and potentially cell death. The study provided valuable mechanistic insights into the synergistic bactericidal effects of non-thermal US+UV treatment and offered a molecular basis for its application in food safety interventions.