Exogenous plastic stress: polypropylene-induced phenotypic alterations and oxidative stress adaptation in Pseudomonas aeruginosa

Polypropylene (PP) products are extensively utilized in both clinical and laboratory environments due to their advantageous physicochemical properties and cost-effectiveness. In this study, we investigated phenotypic alterations and oxidative stress responses of Pseudomonas aeruginosa (PA) under short-term PP exposure (24 h) through three experimental treatments: 0 mg/L PP (control), 10 mg/L PP (low concentration), and 1000 mg/L PP (high concentration). The results demonstrated that, compared to the control group, treatment with the low concentration and high concentration groups of PA led to enhanced resistance to four antibiotics: ciprofloxacin, imipenem, amikacin, and gentamicin. Biofilm formation increased by 45.68% and 140.93%, respectively, while pyocyanin production rose by 42.77% and 62.07%, respectively. At the same time, both swimming and twitching motilities were significantly enhanced. Furthermore, after treatment with the low- and high-concentration groups, the levels of H₂O₂ increased by 103.44% and 149.97%, respectively, malondialdehyde by 89.10% and 210.87%, and glutathione by 50.40% and 83.47%, respectively. Molecular dynamics simulations revealed that PP spontaneously formed a stable complex with the LasR receptor protein in PA through hydrogen bond interactions. The study concluded that under PP stress, PA exhibited enhanced resistance to certain antibiotics, altered phenotypic traits, and increased oxidative stress responses. These findings provide novel insights for public health strategies in preventing PA infections.