Peritonitis in peritoneal dialysis: Bacterial colonization by biofilm spread along the catheter surface

Abstract

We have used modern techniques of direct microscopic examination and quantitative bacterial recovery to show the existence of a route of bacterial colonization along the external and internal surfaces of Tenckhoff catheters implanted in experimental animals. The external route of progressive bacterial colonization extends from the cutaneous exit site through the dacron cuff and into the peritoneum. Bacterial growth along this route consists primarily of glycocalyx enclosed bacterial biofilms adherent to catheter and tissue surfaces, and this surface colonization may or may not give rise to peritoneal infection in which free-living bacteria are found in the peritoneal fluid. The rate of this progressive bacterial colonization depends on the degree of bacterial contamination of the exit site at the time of implantation. Exit site sterilization (hibitane) delays the process while inoculation with rabbit skin strains of Staphylococcus epidermidis accelerates it. Even with optimal implantation techniques, bacterial colonization proceeds via this subcutaneous route so that most Tenckhoff catheter surfaces are covered with a bacterial biofilm, consisting predominantly of gram positive cocci, within three weeks after the implantation of these devices. The rate of bacterial biofilm development on both surfaces of these Tenckhoff catheters, the bacterial colonization of peritoneal tissues, and the dissemination of bacteria into the peritoneal fluid are all significantly accelerated by dialysis in this experimental animal model of continuous ambulatory peritoneal dialysis (CAPD).

Amikacin, Ceftazidime, and Flucloxacillin against Suspended and Adherent Pseudomonas aeruginosa and Staphylococcus epidermidis in an In Vitro Model of Infection

“…Thus, the slow bactericidal effect observed with in vitro models for the study of antibiotic activity against adherent bacteria might relate more closely to the clinical situation than antibiotic exposure of suspended cultures. In fact, several histologic studies suggest that populations ofadherent organisms can be found in infected patients not only on implanted devices, but also on catheters, native heart valves, or bone structures [7,8,19,20].…”

Effect of Prolonged Subcutaneous Implantation of Peritoneal Catheter on Peritonitis Rate during CAPD: A Prospective Randomized Study

“…This break-in period may prevent dialysate leak and allow more rapid and uncomplicated wound healing [16]. However, even with an optimal implantation technique in a rabbit model of peritoneal dialysis, bacterial colonization proceeds via this subcutaneous route [17]. Most peritoneal catheter surfaces were covered with bacterial biofilm within 3 weeks after the implantation despite delayed beginning of bag exchanges after the implantation [17].…”

Update on the challenging role of biofilms in peritoneal dialysis

“…Overall, these studies (Table 1) demonstrate the presence of a microbial biofilm on the catheter surface, despite the absence of infection, suggesting that it is not the infectious process that gives rise to colonization, but rather that biofilms may act as a reservoir of microorganisms. Indeed, it has been hypothesized that the development of peritonitis depends on the initiation of dialysis (Read et al 1989;McDermid et al 1993) and on the ability of microorganisms to disperse from the biofilm (Verger et al 1987;Dasgupta et al 1992). However, further studies are required to elucidate the biofilm-associated infections in PD, as it was found that the microorganisms colonizing the catheter may not parallel those causing the peritonitis (Marrie et al 1983;Rodriguez-Carmona et al 2000).…”