Colonization of urinary catheters by bacteria which produce urease leads to an increase in urine pH, followed by deposition of the minerals struvite and hydroxyapatite. Adhesion of these encrusting deposits can be reduced, but not prevented, by using catheters with a smooth surface finish. Chemical methods for preventing encrustation are not completely satisfactory. A better way of preventing encrustation would be to prevent colonization of the catheter by bacteria. This might be achieved by controlled release of antimicrobial agents directly into the urine from the catheter itself. Preliminary experiments have demonstrated the feasibility of controlled release from solid silicone. However, a simpler approach is diffusion of an antimicrobial agent from a solution within the retention balloon of the catheter. Further experiments are required to determine the concentrations required and whether they are achievable in practice.
Bibby, J. M.; Cox, A. J.; and Hukins, D. W. L.
"Feasability of Preventing Encrustation of Urinary Catheters,"
Cells and Materials: Vol. 5
, Article 7.
Available at: http://digitalcommons.usu.edu/cellsandmaterials/vol5/iss2/7