Establishing an Experimental Infection Model for Peritoneal Dialysis: Effect of Inoculum and Volume

The effect of the number of bacteria and the volume of the inoculum was studied in an experimental infection model to establish a peritoneal dialysis model in the rat. Staphylococcus aureus was used in all experiments, and Staphylococcus epidermidis only in the volume experiments. A bacterial number between 108 and 109 colony forming units (cfu) resulted in a time-dependent decrease of bacteria collected from the peritoneal cavity. Higher concentrations resulted in the death of animals, while lower concentrations were rapidly cleared. There was a positive correlation between the volume in which 3 x 108 cfu were dissolved and the number of bacteria isolated from the peritoneal cavity 24 hours after infection. The results of this study led to an experimental dialysis model using 10 mL of dialysis fluid and 0.5 mL of a suspension containing 3 x 108 cfu of Staphylococcus aureus.