Bacterial colonization and endotoxin contamination of intravenous infusion fluids

Bacterial colonization and endotoxin contamination of intravenous infusion fluids and catheter systems were examined in a surgical intensive care unit. Nineteen consecutive patients were randomly assigned to 48 h (N = 8) or 96 h (N = 11) change of infusion systems. Fluid from infusion bottles (51), infusion bottles plus burettes (102) and catheter systems (104) was cultured quantitatively for aerobic and anaerobic bacteria. Swabs (362) were taken from three-way stopcocks before and after the in-line infusion filters. Total and free endotoxin levels in infusion fluids were measured by quantitative chromogenic Limulus assay. The overall rate of bacterial colonization of bottles/burettes was 7.8% at 48 h and 15.7% at 96 h, while colonization rates of catheter fluid were 34.0% and 24.1%, respectively (n.s.). These high rates of colonization, despite regularly reinforced hand disinfection practices, may be explained by the high frequency of manipulations of the catheter systems, during acute interventions in emergency situations. Cell-bound endotoxin was found in 8.8% of the samples, but only 2.5% of the samples contained free endotoxin. The data support the use of in-line infusion filters, with bacterial-retaining property; however, these filters need not have endotoxin-retaining properties.