Transcriptomic regulation of Salmonella Typhimurium during sonophotocatalysis and the effect of stress adaptation on the antibiotic resistance and tolerance post-treatment

[Display omitted] •Adaptation of S. Typhimurium to external stress determines the efficacy of SPC.•Selection of AR and tolerance during SPC was dependent on the initial stress.•Expression of flagellar genes was nullified by metabolic and stress response genes.•SPC causes attenuation of S. Typhimurium in different organs of BALB/c mice model. Bacterial adaptation to external stress and its consequential evolution to antibiotic resistance (AR) poses a huge risk to the health sector. Conventional wastewater treatment and disinfection technologies may often end up disseminating AR to the environment. Although new technologies to treat water are emerging, AR and antibiotic tolerance induced by the treatment and the significance of bacterial adaptation is unclear. Here, we tested the impact of stress-adapted Salmonella Typhimurium on the efficacy of visible light-assisted sonophotocatalysis (SPC). We show that bacteria adapted to constant and increasing concentrations of kanamycin and hydrogen peroxide could survive SPC treatment for a longer period compared to that of the unadapted bacteria. Importantly, the selection of AR and antibiotic tolerance after the exposure to SPC were dependent on the initial stress adaptation. Transcriptomic analysis reveals that the high expression of flagellar genes in the bacteria subjected to sublethal SPC was counteracted by the genes associated with stress response and metabolism. Finally, SPC treated S. Typhimurium exhibited attenuation in the BALB/c mice model. Our results suggest that SPC is an efficient technique to inactivate S. Typhimurium in water although the efficacy of the system depends on the prior adaptation of the bacteria to external stress.