PHAGOCYTOSIS AND KILLING OF SUSPENDED AND ADHERED BACTERIA BY PERITONEAL-CELLS AFTER DIALYSIS

Objective: To determine the effect of dialysis fluid containing variou s glucose concentrations on the phagocytosis and killing of Staphyloco ccus aureus by rat peritoneal cells under conditions mimicking the in vivo situation. Design: Phagocytosis and killing were evaluated by qua ntitation of the killing capacity of macrophages after in vivo phagocy tosis of the bacteria as well as by an in vitro flow cytometric assay of the phagocytosis and killing of adhered bacteria by peritoneal cell s. Animals: Male Wistar rats. Main Outcome Measure: It was expected th at the intraperitoneal administration of dialysis fluid would impair t he capacity of peritoneal cells to eliminate bacteria. Results: The fi rst test revealed no effects of glucose concentration or dwell time on the killing of phagocytosed bacteria by macrophages, median percentag es ranging between 29% and 64%. In the second series of experiments no effect of glucose concentration on the phagocytosis and killing of ad hered bacteria was found either; however, longer dwell times significa ntly enhanced both the phagocytosis (at a dwell time of 1 hour, under 20%; at dwell times of 4 or 18 hours, above 20%, p < 0.02) and the kil ling (at a dwell time of 1 hour, under 53%; at dwell times of 4 and 18 hours, above 70%, p < 0.01). Conclusions: Glucose concentration has n o effect on the phagocytosis and killing of Staphylococcus aureus, whe reas the dwell time significantly enhances both of these functional ca pacities of peritoneal cells if the bacteria are adhered to surfaces.