Novel methods for the prevention of infection of intravascular devices.

Infections are often caused by bacteria that gain access either from the skin during insertion, or by migration from the skin to the surrounding subcutaneous tissue, once in situ. It is necessary to understand the pathogenesis with regard to sessile or planktonic forms of microorganisms and why they adhere to catheter surfaces, and the interactions between host, catheter and bug. To prevent colonization two general approaches have been adopted: the first concerns the site of insertion-prophylactic antibiotics, tunnelling, intraluminal antibiotic locks, topical application of antibiotics or antiseptics, cutaneous disinfection pre- and post-insertion with various antiseptics, catheter site care and frequency of dressing changes. The second approach considers the physical nature of catheter material-silver impregnated subcutaneous collagen cuffs, antiseptic hubs, antimicrobial coating of catheters with antibiotics e.g., rifampicin and minocycline, silver ions, chlorhexidine, chlorhexidine and silver sulphadiazine. Only by understanding the pathogenesis of catheter devices whereby micro-organisms are embedded in biofilms and are resistant to the action of antibiotics, will effective preventative measures be possible. In addition a proper risk-management review will be necessary to determine the cost-benefit of such modified catheters.