ANTIMICROBIAL ACTIVITY AND BIOCOMPATIBILITY OF POLYURETHANE AND SILICONE CATHETERS CONTAINING LOW CONCENTRATIONS OF SILVER - A NEW PERSPECTIVE IN PREVENTION OF POLYMER-ASSOCIATED FOREIGN-BODY-INFECTIONS

In modern medicine, infection is one of the most serious complications of implanted plastic devices. The host is not able to overcome this s pecial type of opportunistic infection despite having a normal immune response and a low virulence of most of the bacteria involved. Antimic robial therapy alone generally cannot cure the infection and the remov al of catheters often remains the only choice of therapy. Bacterial ad hesion to the polymer surface of the catheter, be it luminal or extern al, is an important step in the pathogenesis of catheter-associated in fections. In this report, we describe new approaches to the prevention of infections by impregnation of polyurethane and silicone with silve r by two different methods. The antimicrobial activity of these silver -impregnated catheters is more than 10 fold higher for coagulase-negat ive staphylococci (CNS) compared to catheters without silver. Similar results are obtained with other microbial organisms like Staphylococcu s aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aerugin osa and Candida albicans. The new polymers show no cytotoxic or thromb ogenic side effects in vitro.