Prolonged antimicrobial activity of a catheter containing chlorhexidine-silver sulfadiazine extends protection against catheter infections in vivo

The present study evaluated in vitro and in vivo a new chlorhexidine (C)-si lver sulfadiazine (S) vascular catheter (the CS2 catheter) characterized by a higher C content and by the extended release of the surface-bound antimi crobials, The CS2 catheter was compared with a first-generation, commercial ly available CS catheter (the CS1 catheter), The CS2 catheter produced slig htly smaller zones of inhibition (mean difference, 0.9 mm [P < 0.001]) at 2 4 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 cathete r insertion. The CS2 catheter retained its antimicrobial activity significa ntly longer in vitro and in vivo (half-lifes exceeded 34 and 7 days, respec tively) and was also significantly more efficacious in preventing a cathete r infection when 10(6) CFU of S. aureus was inoculated 2 days after cathete r implantation (P < 0.001). These results suggest that prolonged anti-infec tive activity on the external catheter surface provides improved efficacy i n the prevention of infection.