Effect of samarium oxide nanoparticles on virulence factors and motility of multi-drug resistant Pseudomonas aeruginosa.

Biofilm formation and quorum sensing (QS) dependent virulence factors are considered the major causes of the emergence of drug resistance, therapeutic failure and development of Pseudomonas aeruginosa infections. This study aimed to investigate the effects of samarium oxide nanoparticles (SmONPs) on biofilm, virulence factors, and motility of multidrug-resistant P. aeruginosa. SmONPs were synthesized using curcumin and characterized by Transmission Electron Microscopy, X-ray diffractometer, Field Emission Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy. Minimum inhibitory concentration (MIC) was determined using broth microdilution method. The antibiofilm potential of SmONPs was also evaluated by crystal violet staining and light microscopy examination. Then, the effect of sub-MICs concentrations of SmONPs on the proteolytic and hemolytic activities of P. aeruginosa was investigated. Finally, the effect of SmONPs on various types of motility including swarming, swimming, and twitching was studied. Our results showed that SmONPs significantly inhibited biofilm formation of P. aeruginosa by 49-61%. Additionally, sub-MICs concentrations of SmONPs effectively decreased virulence factors including pyocyanin (33-55%), protease (24-45%), and hemolytic activity (22-41%). Moreover, swarming, swimming, and twitching motility remarkably was reduced after exposure to the NPs. The findings of this work showed that SmONPs have a high potential in inhibiting QS-dependent virulence of P. aeruginosa, which could be considered for antibacterial chemotherapy after further characterization.