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)-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-lives 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.

Minocycline and ethylenediaminetetraacetate for the prevention of recurrent vascular catheter infections.

Three patients with recurrent vascular catheter-related bacteremia were successfully treated by allowing a solution of minocycline and ethylenediaminetetraacetate (EDTA) to dwell in the lumen of the indwelling catheter or by coating polyurethane catheters with minocycline/EDTA and flushing the lumen daily with the same solution. In vitro and in vivo experiments showed that minocycline/EDTA may have broad-spectrum antimicrobial activity, may have optimal anticoagulant activity, and may be highly efficacious in preventing catheter colonization.

An outbreak of infections with Acinetobacter calcoaceticus in burn patients: contamination of patients' mattresses.

During a 21-month period Acinetobacter calcoaceticus was the most common organism causing infections in a university burn center. Forty-three of 103 patients admitted became infected with this organism. Risk factors associated with burn wound colonization with Acinetobacter included larger burns and Foley catheter use; however, only a longer duration of hospitalization was an independent discriminator of colonization. Infection-control measures, including strict isolation and closure and repainting of the burn unit, did not prevent the transmission of Acinetobacter. An investigation found that wet mattresses served as environmental reservoirs of Acinetobacter. This finding led to a policy of discarding each patient's mattress on the day of the patient's discharge from the burn unit. Life table analysis demonstrated that this intervention led to a reduced risk of burn wound colonization with Acinetobacter (P less than .05) and ultimately resulted in the complete elimination of the organism from the burn unit.