Spontaneous peritonitis and peritoneal fibrosis in rats on peritoneal dialysis for 9 weeks.

To investigate characteristics of peritonitis in rats on peritoneal dialysis (PD), we retrospectively studied 36 cases of peritonitis in 23 rats. After breakin dialysis postcatheter insertion, the animals were dialyzed twice daily with 1.5% or 4.25% Dianeal for 8 weeks. White blood cell (WBC) count with differentials and microbiological culture of the dialysate were examined twice weekly. Peritonitis was treated with cefazolin and tobramycin until the tenth day after the dialysate became clear. The peritoneal equilibration test (PET) was performed at weeks 2, 6, and 10. The dialysate was obtained at 0, 2, and 4 hours for glucose assay. The peritoneal cavity was inspected, and peritoneal tissue specimens were taken. There were 10 single episodes of peritonitis, 7 recurrences, and 6 reinfections. The organisms isolated were Staphylococcus aureus in 24 cases of peritonitis and Escherichia coli in 6 cases of peritonitis. The average treatment period was 16 days. The glucose absorption ratio became higher over time in single episodes of peritonitis, but was unchanged in recurrences and reinfections. Sixteen adhesions, 1 abscess, and 12 sclerotic retractions of the mesentery were observed. Fibrotic thickening of the peritoneum was found histologically in all animals. In spontaneous peritonitis in rats, we often found complicated clinical courses, catheter closure, intraperitoneal adhesion, and fibrotic thickening of the peritoneum.