The aim of this study was to assess the beneficial inhibitory effect of silver nanoparticles immobilized on SiO or TiO on biofilm formation by -one of the most dangerous pathogens isolated from urine and bronchoalveolar lavage fluid of patients hospitalized in intensive care units. Pure and silver doped nanoparticles of SiO and TiO were prepared using a novel modified sol-gel method. Ten clinical strains of and the reference PAO1 strain were used. The minimal inhibitory concentration (MIC) was determined by the broth microdilution method. The minimal biofilm inhibitory concentration (MBIC) and biofilm formation were assessed by colorimetric assay. Bacterial enumeration was used to assess the viability of bacteria in the biofilm. Silver nanoparticles immobilized on the SiO and TiO indicated high antibacterial efficacy against planktonic and biofilm cultures. TiO/Ag showed a better bactericidal effect than SiO/Ag. Our results indicate that the inorganic compounds (SiO, TiO) after nanotechnological modification may be successfully used as antibacterial agents against multidrug-resistant strains.