Oxidative treatment for reducing persistent populations of Escherichia coli under amoxicillin and gentamicin pressure.
CORRÊA, Bruna Carolina; PEREIRA, Maria Vitória Silva; BLANCO, Kate Cristina; BAGNATO, Vanderlei Salvador.
CORRÊA, Bruna Carolina; PEREIRA, Maria Vitória Silva; BLANCO, Kate Cristina; BAGNATO, Vanderlei Salvador.
Abstract: Bacterial persistence is a transient phenotypic state in which a subpopulation of cells survives antibiotic exposure without genetic resistance. These dormant, low-metabolic cells are linked to recurrent infections and reduced antibiotic efficacy. Photodynamic inactivation (PDI), which generates reactive oxygen species (ROS) through photosensitizer activation under visible light, is a promising strategy to counteract persistence. This study evaluated PDI effects on Escherichia coli under amoxicillin and gentamicin pressure, using time-kill assays and MDK99/MDK99.99 metrics. PDI, optimized with methylene blue (10 µM) and 10 J/cm2 light at 660 nm, was applied to antibiotic-exposed cells and progeny. For amoxicillin, PDI reduced MDK99 from > 3 to 2 h; for gentamicin, it suppressed regrowth in progeny and reduced MDK99.99 from 3 to 2 h. Scanning electron microscopy showed morphological damage consistent with persistence. PDI enhanced antibiotic efficacy and shortened treatment time, supporting further investigation of PDI-antibiotic combinations for chronic infections.
@article={003294510,author = {CORRÊA, Bruna Carolina; PEREIRA, Maria Vitória Silva; BLANCO, Kate Cristina; BAGNATO, Vanderlei Salvador.},title={Oxidative treatment for reducing persistent populations of Escherichia coli under amoxicillin and gentamicin pressure},journal={Journal of Biophotonics},note={v. 19, n. 3, p. e70212-1-e70212-8},year={2026}}