Antimicrobial strategies of nanoparticles and chelating agents for mitigating Staphylococcus spp. contamination on slaughterhouse surfaces

The rise of multidrug-resistant (MDR) staphylococci in the food industry, particularly in slaughterhouses, necessitates the development of innovative disinfection strategies. To address the challenge of antimicrobial resistance, this study investigated formulations based on the combination of nanoparticles (NPs) with chelating agents as a robust alternative to conventional disinfectants. The synergistic antimicrobial potential of NPs combined individually with chelating agents, specifically EDTA or a disinfection formulation (HLE, based on hydrogen peroxide, lactic acid and EDTA), against planktonic and MDR staphylococci cells within biofilms was tested in this study. NPs exhibited synergistic antimicrobial activity when combined with EDTA or with HLE, significantly enhancing the inhibition of both planktonic and sessile cells. While prolonged exposure to sublethal concentrations of NPs triggered the emergence of persister cells, it unexpectedly led to a reversion of antibiotic resistance in some cases and the increased susceptibility to almost all antibiotics tested. Downregulation of both specific and non-specific resistance genes, including ermA, ereB, sul1, tolC, and catB3 were observed and also linked to profound morphological shifts. We conclude that by inducing a reversion of the resistant phenotype and downregulating mobile resistance genes, these formulations not only effectively sanitize environmental surfaces but also mitigate the dissemination of MDR bacteria within the food chain and the environment