Reduction of biofilm formation with trisodium citrate in haemodialysis catheters: a randomized controlled trial.
BACKGROUND
Formation of an intraluminal microbial biofilm is noted to play a significant role in the development of catheter-related infections (CRIs). Recently, it has been demonstrated that trisodium citrate (TSC) has superior antimicrobial effects over heparin for catheter locking. In this randomized controlled trial, we compared the influence of catheter locking with heparin and TSC on the in vivo intraluminal biofilm formation in haemodialysis catheters.


METHODS
Six patients were studied from the time of catheter insertion for haemodialysis treatment. They were randomly assigned to TSC 30% or heparin 5000 U/ml for catheter locking for the duration of 1 month. After elective guidewire exchange of the catheter, the locking solution was also changed. After removal, catheters were dissected in three segments and examined by standardized scanning electron microscopy (SEM) to assess quantitative biofilm formation. Furthermore, standardized cultures of all segments were performed to identify any microorganisms.


RESULTS
In catheters filled with TSC, the average coverage by biofilm was 16% versus 63% in the heparin group (P < 0.001). A total of eight subsegments were associated with local catheter infection in the patients who were randomized to heparin locking versus three subsegments who were assigned to TSC (P < 0.05).


CONCLUSIONS
Our study demonstrates that using TSC 30% for catheter locking reduces the formation of microbial biofilm in haemodialysis catheters and culture-positive colonization. It is likely that this is the explanation for the observed prevention of CRIs by TSC locking.