Prevention of catheter sepsis by antibiotic bonding

The techniques of antibiotic bonding were applied to the problem of hyperalimentation catheter sepsis. Pretreatment with tridodecylmethylammonium chloride (TDMAC) increased the bonding of 14C-penicillin to polyethylene catheter segments from 3.1 to 212 micrograms/cm and to silicone elastomer catheter segments from 0.09 to 181 micrograms/cm. The elution of the bound ligands from silicone elastomer catheter segments in the presence of plasma was studied. At 2 weeks more than 60% of the bound TDMAC remained adherent to the catheter. The elution of the bonded penicillin from the silicone elastomer catheters was biphasic, initially 95% dissociated after 48 hours of incubation. A bioassay revealed that the dissociated penicillin was bacteriocidal. Polyethylene catheters were placed in the jugular vein of rats and positioned in the right atrium. The catheters were tunneled posteriorly, exited between the forelimb shoulder girdles, and connected to a swivel mechanism. The exit site was inoculated before closure with 1 X 10(8) Staphylococcus aureus. Five days after insertion the catheters were removed via sterile thoracotomy and the tips cultured. Untreated control catheters, catheters treated by antibiotic soaking, and catheters pretreated with TDMAC all had high rates of catheter colonization (60% to 80)%. TDMAC-penicillin-bonded catheters did not become colonized. This difference was significant (p less than 0.005). Antibiotic bonding may prove effective in preventing hyperalimentation catheter sepsis.