Inhibition of Pseudomonas aeruginosa Biofilm Formation and Quorum Sensing System by Extracts of Prunus avium Stalk

Abstract

Recently, misuse or overuse of antibiotics has led to antibiotic resistance problem, a global healthcare problem. Most virulence factors and biofilm formation in Pseudomonas aeruginosa are controlled by quorum sensing (QS). The inhibition of QS system by inhibitor molecules has been suggested as a novel alternative antivirulence approach in which no need to kill the bacteria.In the present study, QS and biofilm inhibitory potentials of the methanol and acetone extracts of Prunus avium stalk against P. aeruginosa were evaluated. The extracts were tested at the concentrations of 240, 120, and 60 μg/ml. lasB-gfp, rhlA-gfp, pqsA-gfp biosensor strains and P. aeruginosa PAO1 were used to monitor QS and biofilm inhibition, respectively. Fluorescence and absorbance measurements were performed on Cytation 3 multimode microplate reader. QS inhibition ratios for las, rhl, and pqs systems and biofilm inhibition ratios of the acetone extracts were recorded as 70.43%, 47.25%, 76.31%, and 47.76% (±6,60) and of the methanol extracts as 74.96%, 40.10%, 71.89%, and 38.54% (±3,56) at a certain concentration of 240 μg/ml, respectively. As a result, anti-QS and anti-biofilm properties of acetone extracts were better than that of methanol extracts. Further investigations are needed to discover inhibitor compounds of P. avium and also their effects on human cells and then these compounds may be used in new drug discoveries.