Durability of anti-infective effect of long-term silicons sheath cathetersimpregnated with antimicrobial agents

This study was performed to test the long-term antimicrobial efficacy of im pregnated silicone catheters comprising an antimicrobial layer sandwiched b etween an external surface sheath and a luminal surface silicone sheath. Th e design of the catheter permits the introduction of various antimicrobials in addition to anticoagulants or antifibrins in the antimicrobial layer an d allows their gradual release over a period of months after insertion. The in vitro data presented show that the catheter can provide antimicrobial a ctivity for 90 days, after being replated for 15 7-day cycles of replating. When the catheters mere immersed in human serum and incubated at 37 degree sC, they demonstrated significant antimicrobial activity after more than 32 5 days of incubation. The significant long-term in vitro antimicrobial acti vity observed may imply effective in vivo activity for almost 1 year after insertion and could serve as a cost effective alternative to surgically imp lantable silicone catheters.