Management of virulence in Pseudomonas aeruginosa and Serratia marcescens using environmentally-friendly titanium dioxide nanoparticles.

Antimicrobial resistance (AMR), a condition in which the efficacy of antimicrobial drugs in fighting microorganisms is reduced, has become a global challenge. Multidrug resistance (MDR) has been developing in microorganisms, where they can resist multiple medications. In particular, there has been a rise in MDR as well as extensively drug-resistant (XDR) strains of Pseudomonas aeruginosa in some regions, with prevalence rates ranging from 15% to 30%. The application of nanotechnology ranges from diagnostics to drug-delivery systems, revolutionizing healthcare, and improving disease treatment. We aimed to investigate the efficacy of titanium dioxide nanoparticles (TiO 2 -NPs) against various virulent traits of P. aeruginosa and S. marcescens . More than 50% reduction in the production of virulent pigments of P. aeruginosa was recorded following the treatment of TiO 2 -NPs. Additionally, elastases and exoproteases were inhibited by 58.21 and 74.36%, respectively. A similar result was observed against the rhamnolipid production and swimming motility of P. aeruginosa . The effect of TiO 2 -NPs was also validated against another opportunistic pathogen, S. marcescens , where the production of prodigiosin was reduced by 64.78%. Also, a roughly 75% attenuation of proteolytic activity and more than 50% reduction in swarming motility were found. In the control group, the cell surface hydrophobicity was 77.72%, which decreased to 24.67% with the addition of 64 μg ml -1 TiO 2 -NPs in culture media. The hydrophobicity index of microorganisms is crucial for their initial attachment and the formation of biofilms. In conclusion, TiO 2 -NPs demonstrated potential in a multi-target approach against P. aeruginosa and S. marcescens , suggesting their advantages in the prevention and treatment of infections. These nanomaterials could have vital importance in the development of novel antibacterial agents to combat drug-resistant bacteria.