Novel antibiofilm strategies against Pseudomonas aeruginosa NG4 using oleic acid and indole-3-butyric acid.

Biofilm-associated infections caused by Pseudomonas aeruginosa are highly tolerant to conventional antibiotics, driving the search for novel agents capable of disrupting biofilm formation and associated virulence traits. In this study, the antibiofilm, anti-motility, and growth inhibitory effects of indole-3-butyric acid (IBA) and oleic acid (OA) were evaluated against pathogenic P. aeruginosa NG4. Biofilm biomass was quantified by crystal violet staining. The swarming and swimming motility were assessed on semi-solid agar, and planktonic growth was measured spectrophotometrically. Confocal laser scanning microscopy (CLSM) was used to visualise the biofilm structure. Both IBA and OA exhibited potent antibiofilm activity at low concentrations, with ~ 50% and ~ 54% inhibition, respectively, at 5 µg/mL, without affecting planktonic growth. Higher concentrations impaired bacterial proliferation, and both agents significantly reduced swarming motility, with OA exerting slightly greater inhibition. A significant breakdown of biofilm architecture was evident in CLSM images following treatment. To the best of our knowledge, this is the first study to demonstrate that IBA and OA exert significant antibiofilm and anti-motility effects against P. aeruginosa NG4 at low concentrations under the conditions tested, providing a foundation for future mechanistic and biological investigations.