Prolonged Antimicrobial Activity of a Catheter Containing Chlorhexidine-Silver Sulfadiazine Extends Protection against Catheter Infections In Vivo

Abstract

ABSTRACT The present study evaluated in vitro and in vivo a new chlorhexidine (C)-silver sulfadiazine (S) vascular catheter (the CS2 catheter) characterized by a higher C content and by the extended release of the surface-bound antimicrobials. The CS2 catheter was compared with a first-generation, commercially available CS catheter (the CS1 catheter). The CS2 catheter produced slightly smaller zones of inhibition (mean difference, 0.9 mm [ P < 0.001]) at 24 h against Staphylococcus aureus and five other microorganisms by several different methodologies. However, in a rabbit model, both CS catheters were similarly efficacious in preventing a catheter infection when the rabbits were inoculated with 10 4 to 10 7 CFU of S. aureus at the time of catheter insertion. The CS2 catheter retained its antimicrobial activity significantly longer in vitro and in vivo (half-lifes exceeded 34 and 7 days, respectively) and was also significantly more efficacious in preventing a catheter infection when 10 6 CFU of S. aureus was inoculated 2 days after catheter implantation ( P < 0.001). These results suggest that prolonged anti-infective activity on the external catheter surface provides improved efficacy in the prevention of infection.