A SWINE MODEL FOR THE EVALUATION OF EFFICACY OF ANTIMICROBIAL CATHETER COATINGS

A swine model was developed to investigate the efficacy of percutaneou s venous catheters with anti-microbial coatings. The catheters used in the study consisted of silver-coated and uncoated catheters, both des igned for percutaneous venous access. Five commercial pigs were each i mplanted with three venous catheters and followed for a period of 90 d ays. Two of the three catheters were coated and one was uncoated. To e valuate the percutaneous aspects of the catheters in the model, two ve nous access catheters were implanted percutaneously, parallel to the d orsal midline. These catheters were just caudal to the region that is dorsal to the scapula in each animal. In each case, the catheter to th e left of the dorsal midline was silver-coated while the catheter to t he right of the dorsal midline was uncoated. A silver-coated catheter was also implanted in the left external jugular vein of each animal an d buried subcutaneously in order to evaluate the elution of the coatin g through the body under venous contact. Over the 90 day period, the c oncentration of silver in the blood rose to a mean peak level of 23.2 ppb following implantation of the catheters and then decreased after t he second post-surgery week. The histological evaluation and macroscop ic inspection at necropsy revealed minimal tissue response to both coa ted and uncoated materials. Data on bacterial growth indicated that ba cteria were present at the terminal subcutaneous end of two of the unc oated percutaneous catheters. Based upon serum silver levels, exudate formation, histological examination, and bacterial growth information, the swine model was deemed to be suitable for testing the efficacy of catheters containing anti-microbial coatings.