Opsonic deficiency of peritoneal dialysis effluent in continuous ambulatory peritoneal dialysis.
Staphylococcus epidermidis peritonitis frequently complicates the clinical course of patients treated with continuous ambulatory peritoneal dialysis (CAPD). Since bacterial opsonization is critical to the effective defense of the peritoneal cavity by phagocytic cells, we prospectively evaluated the opsonic activity of peritoneal dialysis effluent obtained from 17 CAPD patients during 102 patient months. Samples of peritoneal dialysis effluent contained concentrations of opsonins against S. epidermidis that were less than 2% of that observed in serum. Moreover, heat-labile opsonic activity against Escherichia coli was absent from all dialysis effluents. During the study, there were ten episodes of peritonitis in nine CAPD patients (1 per 10.2 patient months). S. epidermidis was isolated in seven episodes, a gram-negative bacillus in one, and two episodes were culture negative. the incidence of S. epidermidis peritonitis was 1 per 62 patient months in the patients with "high" peritoneal dialysis effluent opsonic activity against S. epidermidis but was nearly tenfold greater in patients with "low" opsonic activity (1 per 6.7 patient months). We conclude that peritoneal dialysis effluent opsonic activity predicts which CAPD patients are at an increased risk to develop S. epidermidis peritonitis.