Ultrastructure analysis of Tenckhoff chronic peritoneal catheters used in continuous ambulatory peritoneal dialysis patients.

The luminal and external surfaces of 18 curled silicone double-cuff catheters removed from patients who had been on continuous ambulatory peritoneal dialysis (CAPD) for 2-77 months (average 37 +/- 21 months) were analyzed by scanning electron microscopy (SEM) and microbiological cultures. Eight catheters (G1) were removed due to recurrent peritonitis or peritonitis refractory to antibiotic management, and the others (G2) due to local or clinical problems. The peritonitis rate was one episode every 24 patient-months in G1, and 80 patient-months in G2. All catheter surfaces were covered with proteinlike granular deposits (0.15 +/- 0.11/cm); 6 catheters were covered by microbial biofilm (0.24 +/- 0.16/cm). Positive cultures of catheter segments were obtained in 6 cases (4 for G1 and 2 for G2) with a preponderance (33%) of Staphylococcus aureus among the cultivated bacteria. Structural defects and small linear tears were present on both luminal and external surfaces in 8 catheters. Structural defects were frequent in the catheters removed for recurrent peritonitis. Linear tears appeared more frequently in the catheters used for a longer time. Structural defects of catheter surfaces were also discovered in the newer devices. The structural defects of the catheter appear to facilitate microbial adhesion and colonization and to predispose the patient to recurrence of peritonitis. A better catheter design and an improvement in the production process should therefore be recommended.