Patterns of infection in patients maintained on long-term peritoneal dialysis therapy with multiple episodes of peritonitis

The causes of peritonitis in patients with end-stage renal disease maintained on long-term peritoneal dialysis (PD) are unclear. One possible explanation for peritonitis, particularly in patients with multiple episodes of infection, is the release of planktonic bacteria from biofilm on the walls of catheters. Bacteria form biofilm on the walls of catheters within 48 hours of their placement. If this explanation were correct, one would expect there to be reappearance of organisms causing infection in patients with multiple episodes of peritonitis. The charts of all patients starting long-term PD at New Haven CAPD from January 1, 1990, through July 31, 2000, were reviewed. Patients were included in the study if they had experienced more than one episode of culture-positive peritonitis and complete data were available concerning cultured organisms and antibiotic sensitivity patterns. Episodes of infection, organisms, and sensitivities and catheter changes were reviewed. Of 630 patients, 198 were identified as meeting these criteria. There were 114 men; 104 patients were white. Of 198 patients, 157 (80%) had at least one repeat infection with the same organism. In 124 (79%) patients, more than 50% of the peritonitis episodes were caused by the same organism. Of 90 patients who had more than four episodes of infection in their history, 59 (65%) had at least half or more of their episodes caused by the same organism. Sequential analyses for independence revealed that for Staphylococcus epidermidis and for Staphylococcus aureus, there was a significantly increased likelihood for these organisms to follow themselves as causative organisms of peritonitis. When the data were analyzed using the Spearman correlation test, the results indicated that the likelihood of repeat infections occurring was significantly greater than by chance alone. Of 67 patients with catheter changes and subsequent peritonitis, only 10 (15%) developed repeat infections with the same organism after the catheter change. Eight of these were due to yeast. These data support the hypothesis that bacterial biofilm on the walls of peritoneal catheters may be associated with peritonitis in patients maintained on long-term PD and may contribute to at least some of these episodes of infection. (C) 2002 by the National Kidney Foundation, Inc.