Surface antimicrobial activity of heparin-bonded and antiseptic-impregnated vascular catheters

Most Swan-Ganz pulmonary artery catheters have heparin bonded to the surface with benzalkonium chloride, a cationic surfactant, to reduce thrombosis. Since benzalkonium is bactericidal, the antimicrobial activity of heparin-bonded pulmonary artery catheters was investigated in an in vitro assay. Each catheter exhibited activity against a wide variety of potential microbial pathogens, including Candida albicans. The magnitude of activity against individual organisms correlated strongly with their in vitro susceptibility to benzalkonium chloride (r = .94, P < .002). A chlorhexidine-silver sulfadiazine-impregnated catheter exhibited even greater activity than the heparin-bonded catheters (P = .01). When exposed to serum for 24 h, heparin-bonded catheters lost > or = 50% of their antimicrobial activity, whereas the activity of the chlorhexidine-silver sulfadiazine-impregnated catheter was minimally affected. The fortuitous surface antimicrobial activity of heparin-bonded catheters may account for the low incidence of catheter-related bacteremia (mean, 1.0%) compared with Swan-Ganz catheters of the same materials but not coated with benzalkonium-heparin (mean, 2.8%).