Role of an intraperitoneal catheter implant in the pathogenesis of experimental Staphylococcus epidermidis peritoneal infection in renal failure mice.

Abstract

The influence of a permanent peritoneal catheter implant on the response of renal failure and control mice to peritoneal inoculation with 10(6) colony-forming units (CFU) Staphylococcus epidermidis was assessed 48 h after bacterial challenge. Two weeks after the surgical induction of renal failure or sham surgery, a segment of a peritoneal dialysis catheter was implanted entirely within the confines of the peritoneal cavity of mice. One month later peritoneal S. epidermidis inoculation was performed by transcutaneous injection through the abdominal wall either directly into the peritoneal cavity (i.p.) or via the catheter lumen (i.c.). Following i.p. inoculation, minimal bacterial growth was recovered from the peritoneal structures of all mice, including the peritoneal catheter. In contrast, following i.c. S. epidermidis challenge, the catheter site remained heavily colonized while peritoneal washings and parietal peritoneum again presented minimal bacterial recoveries. S. epidermidis recovery from the catheter site of renal failure mice was significantly greater than from the respective site of sham-operated controls. Scanning electron microscopy of catheter segments recovered from mice following i.c. inoculation revealed single cocci or microcolonies associated with the catheter surface and differential leukocyte counts of fluid aspirated from the catheter lumen revealed evidence of acute inflammation. Signs of inflammatory processes in peritoneal washings and peripheral blood, however, were not observed. These results are discussed in relation to S. epidermidis peritonitis and continuous ambulatory peritoneal dialysis.