Strain Differences in the Opsonisation of Staphylococcus Epidermidis

Abstract

Ten isolates of coagulase-negative staphylococci, collected from patients receiving treatment with continuous ambulatory peritoneal dialysis (CAPD), exhibited marked differences in the degree of opsonisation when incubated in 10% and 1% pooled human serum, 10% and 1% heat-treated serum, Hanks’ Balanced Salt Solution, and timed peritoneal dialysis (PD) effluent. The addition of exogenous IgG to PD effluent results in a greater increase in opsonisation in those fluids with the weakest inherent opsonic activity, but is ineffective against the majority of isolates in the absence of heat-Iabile opsonic activity. The results of this in vitro study suggest that host resistance to CAPD peritonitis due to coagulasenegative staphylococci may be determined as much by the characteristics of the contaminating strain, as by the opsonising activity of PD effluent.

Automated Peritoneal Dialysis Symposium: Host Defenses in APD

“…Effluent obtained from CAPD patients contains many fewer white blood cells (WBCs). This is, in part, the result of dilution and loss of cells during the fluid exchanges (31). We could demonstrate that in both patient groups (NIPD and CCPD) the number of PMOs increased five times, up to a mean of 5 × 10 4 /ml, after the exchange‐free interval of 12–14 hours.…”

Effect of Peritoneal Dialysis on Peritoneal Macrophages

“…It was estimated that at least 5 x 105 macrophages/mL are needed to suppress bacterial growth (17). Efflu ent obtained from PD patients, on the other hand, contains a much lower WBC count, approximately 104 cells/mL ( 18). Cell number imposes important restrictive effects on phagocyte function (19), as it reduces the likelihood of interaction with invading organisms.…”