Treatment of long-term intravascular catheter-related bacteraemia with antibiotic lock: randomized,...

The use of an antibiotic lock (AB-lock) for the treatment of catheter-related bloodstream infection (CRBSI) has been suggested, but randomized trials have never been performed.

A randomized, blinded, multicentre trial was set up to compare an AB-lock-containing vancomycin for Gram-positive or ceftazidime for Gram-negative bacteria-with placebo, in addition to parenteral AB therapy. We included only CRBSI from a long-term intravascular device (LTID) whether tunnelled or totally implanted.

During 30 months, 174 patients with an LTID and bacteraemia were evaluated, of whom 85 had a CRBSI. Forty-six patients were included. Frequent reasons for exclusion were: catheter not vacant for >8-12 h/day for the AB-lock (n =10); yeast infection or mixed Gram-positive/negative infections (n =13); catheter removal preferred by the treating physician (n =7); and CRBSI <14 days after insertion or pocket/tunnel infection (n =10). Forty-four patients met the criteria for modified intention-to-treat analysis. The primary endpoint was failure to cure the CRBSI or relapse with the same strain. On study day 180 by Kaplan-Meier analysis, this occurred in 33% (seven of 21) in the AB-lock arm and in 57% (13 of 23) in the placebo arm (hazard ratio 0.55, P =0.10). A relapse with the same strain occurred in 9/23 with the placebo and 3/21 with the AB-lock (P =0.06).

Future studies should take into account the barriers to the use of AB-lock observed in this study. Most importantly, shorter lock dwell times and broader spectrum locks (e.g. antiseptic) should be investigated to target a larger patient population.