Antimicrobial, antibiofilm and antiurease activities of microbially synthesized silver nanoparticles against Proteus mirabilis

Abstract

Nanoparticles (NPs) are tiny materials ranging in size from 1 to 100 nm and have unique magnetic, electrical, optical characteristics differing from the bulk materials. They have broad spectrum of applications in pharmaceuticals, electronics, optics, aviation, construction, and automotive industries. Several physical and chemical techniques such as electrochemical, thermal decomposition, chemical vapor deposition, sonochemical reduction and microwave irradiation have been applied to produce metal NPs. Alternatively, green synthesis offers an environmentally-friendly and simple mean for NP preparation. In the present study, silver NPs were produced by Pseudomonas aeruginosa OG1 strain. Characterization of NPs were performed by TEM, SEM and XRD. These NPs were used against pathogenic Proteus mirabilis, which occurs widely in soil and water and shows high level urease activity and forms clear biofilms. It is the cause of 90% of all Proteus infections and frequently related with the catheter-associated urinary tract infections. Silver NPs obtained in the present study were applied to inhibit the growth, urease production, and biofilm formation of P. mirabilis. Growth inhibition zones of 9 mm and 11 mm and, 60 % and 85% antibiofilm effects were obtained by 100 µg/mL and 200 µg/mL NPs, respectively. Urease activity of P. mirabilis was completely inhibited in both concentrations. These results show that the Ag NPs can be used as effective antimicrobial, antibiofilm, and antiurease agents in the fight against pathogens.