Factors affecting adherence of Staphylococcus epidermidis in peritoneal dialysis solutions

Smith, Janet Dawne (1987) Factors affecting adherence of Staphylococcus epidermidis in peritoneal dialysis solutions. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (13MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

Staphylococcus epidermidis is the most frequent cause of peritonitis complicating continuous ambulatory peritoneal dialysis (CAPD). During CAPD, S. epidermidis presumably enters the peritoneal cavity through the surgical incision along the outer surface of the catheter tubing or less frequently through its lumen. The catheter is a foreign body and the peritoneal dialysis solution (PDS) may support bacterial attachment and growth. -- Virulence mechanisms of S. epidermidis are poorly understood, but adherence properties and the presence of slime on some strains may contribute to this organism's ability to cause peritonitis. -- Using an in vitro model for adherence, eight strains of S. epidermidis (two non-slime and six slime-producers) were tested in fresh and post-dialysis PDS. The effects of various additives (insulin, serum, albumin, and protamine sulfate) and antibiotics (gentamicin, penicillin, and cephalothin) on bacterial adherence to catheters were tested. -- The presence of slime production did not enhance adherence to polyvinyl catheters used in this study. Compared to fresh PDS, there was a significant decrease in bacterial adherence in post-dialysis PDS for all strains tested. Insulin (5 units/mL), 5% serum, protamine sulfate (125 and 250 mg/L), gentamicin (0.06 and 0.12 mg/L), penicillin (0.06 and 0.12 mg/L), and cephalothin (0.12 and 0.25 mg/L) decreased adherence of bacteria to the catheter by at least four-fold compared to controls. A 5.0% concentration of albumin decreased adherence three-fold compared to controls. There was a 1.5-fold decrease in adherence with 0.625% serum, a four-fold decrease with 1.25% and 2.5% serum, and a six-fold decrease with 5.0% serum. The 10.0% serum additive produced nearly a ten-fold decrease in bacterial adherence to the catheter, compared to controls. Also, the 5% serum, heated at 60° C for one hour, decreased adherence two-fold. Scanning electron microscopy confirmed these results. Adherence was greatest in fresh PDS with no additive or antibiotic and least in post-dialysis PDS with an additive or an antibiotic. -- These studies showed that certain therapeutic additives and antibiotics may inhibit pathogenetic mechanisms of S. epidermidis. In vivo studies are required to evaluate whether these results seen in vitro have relevance in the clinical situation.

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