FACTORS AFFECTING IN-VITRO ADHERENCE OF URETERAL STENT BIOFILM ISOLATES TO POLYURETHANE

Adherence of bacteria to biomaterials is the first stage in the develo pment of a device-related infection. The adherence of bacterial cells to biomaterials may be influenced by surface characteristics of the ce ll, its growth conditions and the biomaterial surface chemistry. Follo wing growth in human urine, the cell surface,hydrophobicity and zeta p otential of two ureteral stent biofilm isolates, Enterococcus faecalis and Escherichia coli, were significantly altered. In addition, the ad herence of human urine-grown Enterococcus faecalis and Escherichia col i to polyurethane was significantly increased by up to 52.1% and 58.6% , respectively. Treatment of the polyurethane with human urine rendere d the polymer surface more hydrophilic (mean advancing water contact a ngle reduced from 97.59 degrees to 26.37 degrees). However, organisms grown in human urine showed less adherence (up to 90.4%) to the treate d polymer than those grown in Mueller-Hinton broth. The results presen ted in this study indicate that in vivo conditions should be simulated as far as possible when carrying out in vitro bacterial adherence ass ays, especially if assessing novel methods for reduction of adherence. (C) 1997 Elsevier Science B.V.