PubMed1989
Pretreatment of catheters by a simple new procedure designed to reduce the incidence of septic complications was tested in both in vitro and in vivo studies. In the former experiments, the high sensitivity of gram-negative bacteria and fungi to Silastic (silicone rubber) catheters pretreated with silver nitrate solution was determined. The antimicrobrial activity remained unchanged after both sterilization and up to six weeks of storage. Furthermore, prolonged incubation of treated catheter segments in Escherichia coli inoculated plasma resulted in a significant reduction of organisms in the media and those adherent to the surface of the catheters. The in vivo experiments were performed upon two groups of rabbits. In the first group, catheters (one treated and one untreated) were implanted into contralateral jugular veins. In the second group, alternating treated and control catheter segments were threaded onto polyethylene core tubing; the resulting string of segments was positioned in the inferior vena cava. Five to 11 days after implantation of the catheter, all rabbits were intravenously injected with live E. coli (approximately 10(8) to 10(9) organisms per kilogram of weight); 18 to 24 hours later, the catheters and blood samples were removed for cultivation. Significant reductions in both incidence and magnitude of colonization in treated catheters by E. coli were observed in both rabbit groups. Additionally, histologic examination did not reveal any significant differences between contralateral jugular veins (previously in prolonged and intimate contact with the indwelling catheters), confirming the absence of any local adverse effects of silver nitrate.