Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide. The infection with P. aeruginosa is frequently linked with clinical treatment difficulties given drug resistance and abuse of antibiotics. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity, although the specific mechanism of its action requires additional investigation. Given the regulation effects on quorum sensing (QS), we hypothesized that inhibition of P. aeruginosa with ibuprofen is linked with the QS systems. First, we assessed the action of ibuprofen in P. aeruginosa by measuring CFU. The antimicrobial activity of ibuprofen was evaluated by crystal violent staining and acridine orange staining at various drug concentrations (0, 50, 75, and 100 g/mL). Moreover, the effect of ibuprofen on different QS virulence factors, such as pyocyanin, elastase, protease, and rhamnolipids, was assessed revealing a concentration-dependent decrease (P<0.05). The effect of ibuprofen was confirmed by liquid chromatography/mass spectrometry analysis of 3-oxo-C12-HSL and C4-HSL production. In addition, qRT-PCR results identified significant suppression of Las and Rhl gene expression after 18 hours of treatment with ibuprofen (P<0.05), with the most significant suppression observed at the concentration of 75 g/mL. Functional complementation with exogenous 3-oxo-C12-HSL and C4-HSL suggested that C4-HSL can recover the production of virulence factors and biofilm formation in P. aeruginosa. Molecular docking of ibuprofen with QS-associated proteins revealed high binding affinity. In summary, the results suggest that ibuprofen is a candidate drug for the treatment of clinical infections with P. aeruginosa.