Model of Staphylococcus aureus central venous catheter-associated infection in rats

Background and Purpose: Staphylococcus aureus is an important cause of intravascular catheter-associated bacteremia. We developed a rat central venous catheter (CVC)-associated infection model to study pathogenesis and treatment. Methods: A silastic lumen-within-lumen catheter and rodent- restraint jacket were designed. Subcutaneously tunneled catheters were inserted in the jugular vein of 20 male Sprague Dawley rats. Twelve rats (group 1) were inoculated with S. aureus via the CVC; three rats (group 2) were inoculated with S. aureus via the tail vein, five rats (group 3) served as uninfected controls; and three rats (group 4) were inoculated with S. aureus via the tail vein but did not undergo CVC insertion. Five to eight days after inoculation, animals were euthanized, CVCs were aseptically removed, and quantitative culture was done. Quantitative culture also was performed on blood, heart, liver, lungs, and kidneys. Results: Infection, characterized by bacteremia and metastatic disease, was observed in all rats inoculated via the CVC with as few as 100 colony-forming units (CFU) of S. aureus. Rats of group 2 were not as likely to develop CVC-associated infection, and none of the animals of groups 3 or 4 developed infection. Conclusions: This model of CVC-associated infection should prove suitable for studying pathogenesis and treatment of the condition.