Antimicrobial activity Study of triclosan-loaded WBPU on Proteus mirabilis in vitro

Objectives To evaluate the antimicrobial activity study of triclosan-loaded waterborne polyurethanes (WBPU) on Proteus mirabilis in vitro. Materials and methods Inhibition zone assays on petri plates with triclosan-loaded WBPU samples were used to test its antimicrobial activity on Proteus mirabilis . Models of the catheterized bladder supplied with artificial urine infected with Proteus mirabilis were employed to confirm the antimicrobial activity of triclosan-loaded WBPU. Bacteria colony counting, pH of the residual urine at each time point and catheter blockage time were recorded. Confocal laser scanning microscopy, scanning electron microscopy and encrustation deposits dry weighing were used for evaluating the biofilm formation. Results Inhibition zones formed in the triclosan-loaded WBPU groups in a dose–response manner (the radius for samples with 1, 0.1 and 0.01 mg triclosan were 9.93 ± 1.08, 6.07 ± 0.54 and 2.47 ± 0.25 mm, P < 0.001). The bacterial growth in the triclosan group was markedly inhibited, which was almost undetectable after 12 h of bladder running. Residual urine pH in the control group increased significantly in comparison with the triclosan group (9.50 ± 0.04 vs. 6.17 ± 0.01 at 24 h, P < 0.001). The presence of triclosan-loaded WBPU decreased catheter encrustations and markedly postponed the catheter blockage time, as well as suppressed the Proteus mirabilis biofilm formation (33.9 ± 13.9 mg vs. 1.4 ± 1.5 mg, P = 0.016). Conclusions Triclosan-loaded WBPU significantly inhibited Proteus mirabilis ’ growth and biofilm formation, indicating the promising antibacterial effects on Proteus mirabilis in vitro. Further efforts are under way that involves coating the material onto the urinary catheters and in vivo studies.