A Porcine Model of Staphylococcus epidermidis Catheter-Associated Infection

Abstract

The suitability of using catheterized, partially nephrectomized (uremic) pigs to study catheter-associated infection in peritoneal dialysis was investigated. In some pigs, an inoculum of 10(9) cfu of Staphylococcus epidermidis ATCC 35984 was deposited around the catheter exit site and the organism was allowed to colonize over 21 days. The strain was recoverable from tissues and catheter samples at various locations along the catheter tract from inoculated pigs at postmortem examination. Uninoculated control catheters were colonized to a significantly lesser degree and by various other staphylococcal species. Immune response by inoculated pigs toward catheter-associated bacteria was indicated by a significant increase in serum antistaphylococcal IgG concentration and an increased percentage of peripheral polymorphonuclear leukocytes. Uremia had no significant effect on serologic response. Immunoblotting against S. epidermidis lysostaphin-extracted proteins showed that although incubation with inoculated group antisera produced more intense banding and reacted to a wider range of protein than did antisera from uninoculated controls, common antigenic proteins among the groups were found.

Biofilms and Infection in Dialysis Patients

“…Similar experiments were done in partially nephrectomized pigs to observe the changes in uremia (58). After inoculation of the exit site with S. epidermidis , biofilm colonization progressed just as in the rabbit model, with uremia making no apparent difference in its progression from the exit site to the peritoneum (58).…”

“…Similar experiments were done in partially nephrectomized pigs to observe the changes in uremia (58). After inoculation of the exit site with S. epidermidis, biofilm colonization progressed just as in the rabbit model, with uremia making no apparent difference in its progression from the exit site to the peritoneum (58). These studies confirm the validity of the experimental models of biofilm development and its consequences for biofilmrelated peritonitis in PD patients, either from touch contamination during PD exchanges or from the exit site to the peritoneal cavity.…”

Global Gene Expression in Staphylococcus aureus Biofilms

“…This clearly indicates that the impact of sarA on biofilm formation, at least as defined under in vitro growth conditions, involves a pathway that is independent of the icaADBC operon. The role of ica in vivo has been addressed in S. epidermidis with contradictory results (10,23,41,47,49,55,56,57,62). However, few studies have addressed this issue in S. aureus.…”

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).…”