Efficacy of silver/hydrophilic poly(p-xylylene) on preventing bacterial growth and biofilm formation in urinary catheters

Catheter associated urinary tract infections (CAUTI), caused by several strains of bacteria, are a common complication for catheterized patients. This may eventually lead to a blockage of the catheter due to the formation of a crystalline or amorphous biofilm. Inhibiting bacteria should result in a longer application time free of complaints. This issue has been investigated using an innovative type of silver-coated catheter with a semipermeable cap layer to prevent CAUTI. In this work, two different types of silver catheters were investigated, both of which were capped with poly(p-xylylene) (PPX-N) and exhibited different surface properties that completely changed their wetting conduct with water. The contact angle of conventionally deposited PPX-N is approximately 80°. After O2 plasma treatment, the contact angle drops to approximately 30°. These two systems, Ag/PPX-N and Ag/PPX-N-O2, were tested in synthetic urine at a body temperature of 37 °C. First, the optical density and the inhibition zones of bot...