History

The current study was conducted to investigate the effect of zinc oxide nanoparticles (ZnO–np) prepared by physical method, alcoholic extract of Vitex agnus-castus leaf and biosynthetic ZnO–np by using Vitex agnus-castus extracts on the gene expression of Quorum sensing (QS) system of biofilm-producing Pseudomonas aeruginosa. 100 samples were collected from clinical sources and after the identification, 18 clinical isolates were confirmed to be Pseudomonas aeruginosa by PCR using gyrB gene. The effect of MIC for  all substances against four biofilm-producing isolates were examined by the microtiter plate method. Furthermore, qRT-PCR was performed to determine three substances inhibitory effect on QS-regulatory genes lasR, , rhlR, and pqsR that control virulence factors secretion. Biosynthetic ZnO–np, ZnO–np and plant extract showed significantly down-regulated the expression level of all biofilm and virulence genes of P. aeruginosa clinical isolates and thus we conclude that Biosynthetic ZnO–np can be used as a quorum sensing inhibitor and an anti-biofilm  in P. aeruginosa infections.