Effect of triclosan on the development of bacterial biofilms by urinary tract pathogens on urinary catheters.

OBJECTIVES: To examine (i) the effect of triclosan on the formation of catheter biofilms by urinary tract pathogens and (ii) the diffusion of triclosan through the retention balloons of urinary catheters.

METHODS: Models of the catheterized bladder were infected with eight different urinary tract pathogens and the effect of triclosan on biofilm formation was assessed by determining the numbers of viable cells colonizing the catheters and by scanning electron microscopy. HPLC was used to determine the triclosan concentration in urine draining from models that had been fitted with triclosan-inflated silicone catheters.

RESULTS: When catheters were inflated with triclosan (10 g/L) the formation of catheter biofilm by Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Proteus mirabilis was prevented. The numbers of Enterococcus faecalis and Providencia stuartii cells colonizing catheters were also significantly reduced (P<0.05). Serratia marcescens, Morganella morganii and Pseudomonas aeruginosa, however, were able to produce extensive catheter biofilms in the presence of triclosan. Only P. mirabilis produced alkaline urine and encrusted the catheters. Concentrations of 0.02-0.16 mg/L of the biocide were detected in urine draining from the model over the 48 h experimental period.

CONCLUSIONS: Triclosan diffused through silicone catheter balloons and produced urinary concentrations that prevented catheter encrustation by P. mirabilis and biofilm formation by several other common pathogens of the catheterized urinary tract. It had little effect on urease-producing P. aeruginosa, S. marcescens or M. morganii but these species did not produce alkaline urine or crystalline biofilms.