Efficacy of pulsative flushing on Candida albicans growth inside three-way stopcocks

Background & Aim

Candida albicans (C. albicans) is a common causative pathogen of catheter-related bloodstream infections, resulting in difficult-to-treat candidiasis. Moreover, fluid infusion by total parenteral nutrition (TPN) is commonly combined with lipid emulsion administration from a side tube. We evaluated the growth of C. albicans in closed three-way stopcocks used for simultaneous administration of TPN infusions and lipid emulsions. In addition, the effect of flushing on C. albicans growth was examined.

Methods

A TPN infusion solution and a lipid emulsion were tested using two different closed-type three-way stopcocks. The strain used was C. albicans IFM 61197. Simultaneous administration of the TPN infusion solution (2,000 mL over 24 h) and the lipid emulsion with C. albicans (100 mL over 4 h) were simultaneously administered using the piggyback method and an infusion pump. Flushing with physiological saline was performed via the side tube of the three-way stopcock after lipid emulsion administration. The flushing volumes were 0, 5, 10, and 20 mL. Continuous flushing (CF) and pulsative flushing (PF) were used as flushing methods. The infusion fluid remaining in the three-way stopcock was sampled immediately before completing lipid emulsion administration and 24 h after beginning administration of the TPN infusion solution. From these samples, colony-forming unit (CFU) counts were determined. In addition, after the last sampling at 24 h, the stopcock interior was washed with phosphate-buffered saline, and CFU counts determined.

Results

Without flushing, C. albicans grew in the two types of three-way stopcocks. When flushing with saline after lipid emulsion administration was performed, growth of C. albicans was lower than without flushing. Increasing flushing volume and using PF as the flushing method were found to decrease C. albicans growth in the three-way stopcocks.

Conclusion

As C. albicans growth was reduced inside the three-way stopcock by flushing after lipid emulsion administration, PF was demonstrated as effective against C. albicans growth within the three-way stopcocks. However, experimental results varied substantially, despite using the same experimental procedures. Therefore, proper flushing requires an appropriate level of skill and training to appropriate infusion solution management and operation to prevent microbial contamination.