Potential application of polyisobutylene-polystyrene and a Lactobacillus protein to reduce the risk of device-associated urinary tract infections

Urinary tract infections (UTI) associated with prostheses continue to cause significant morbidity despite the development and implementation of new biomaterials and device coatings. Ureteral stents, placed to improve drainage of the kidney can become a nidus for infection and potentially serious kidney damage, through attachment of pathogens and biofilm formation. The present study investigated two approaches to reducing the risk of ureteral stent infection. The first involved comparing the resistance to bacterial attachment of medical grade silicone rubber, the current gold standard biomaterial for urinary tract devices, to that of polyisobutylene-poly styrene block copolymer (PIB-PS), a polymer with proven biomaterial potential but as yet untested within the urinary tract. The second approach studied the capacity of a recombinant protein (p29) originally isolated from Lactobacillus fermentum RC-14 to inhibit bacterial attachment when used as a device coating. The protein coat was successfully identified by atomic force microscopy (AFM), gel electrophoresis and surface enhanced laser desorption/ionization (SELDI) protein chip analysis and shown to be present for at least 96 h. The coating and the PIB-PS surface alone were found to significantly reduce the attachment of two common uropathogenic species. Escherichia coli 67 and Enterococcus faecalis 1131 in vitro in the presence of phosphate buffered saline alone. However, the effect was negated following additional urine coating of the sections prior to challenge, likely due to p29 desorption and the development of a urinary conditioning film. These findings highlight the complexity of translating in vitro data to the in vivo setting and the critical role urinary constituents play in the development of urinary tract device-associated infections. (C) 2002 Elsevier Science B.V. All rights reserved.