Effect of antimicrobial locks for tunneled hemodialysis catheters on bloodstream infection and bacterial resistance: a quality improvement report

Am J Kidney Dis. 2009 Mar;53(3):492-502. doi: 10.1053/j.ajkd.2008.09.019. Epub 2009 Jan 15.


Background: Catheter-restricted antimicrobial lock (AML) use reduces catheter-associated bloodstream infection (CA-BSI) in clinical trial settings, but may not be as effective in clinical settings and may increase bacterial resistance.

Design: Quality improvement report analyzed using a cross-sectional time series (unbalanced panel) design.

Setting & participants: The study cohort comprised all prevalent adults treated with hemodialysis through a tunneled catheter for any, but not necessarily all, of the time from January 1, 2003, to June 30, 2006, in Manukau City, New Zealand (135,346 catheter-days, 404 tunneled catheters, 320 patients).

Quality improvement plan: Catheter-restricted AMLs (heparin plus gentamicin) for all tunneled catheters from July 1, 2004.

Measures: Repeated observations of CA-BSI, hospitalization, tunneled catheter removal, and death from CA-BSI analyzed by using generalized estimating equations with a single level of clustering for each tunneled catheter and patterns of bacterial resistance analyzed by using simple descriptive statistics.

Results: AML use was associated with reductions in rates of CA-BSI and hospitalization for CA-BSI by 52% and 69% for patients with tunneled catheters locked continuously with AMLs since their insertion compared with those with tunneled catheters that were not, respectively. AML exposure also was associated with a trend to increased gentamicin resistance amongst coagulase-negative staphylococci isolates, a pattern similar to that observed for BSIs in our general hemodialysis population in which tunneled catheters were not the source of BSI, but different from that in the general non-end-stage renal disease population in the region.

Limitations: This is an uncontrolled observational study and cannot prove causality. The follow-up period of 18 months is longer than for other studies, but still too short to definitely answer whether AML use drives bacterial resistance.

Conclusions: A change to use of AMLs may improve clinical outcomes; however, additional study of associated bacterial resistance is needed before AML use becomes standard care.

MeSH terms

  • Aged
  • Anti-Bacterial Agents / therapeutic use*
  • Catheter-Related Infections / prevention & control*
  • Catheters, Indwelling*
  • Cross-Sectional Studies
  • Drug Resistance, Bacterial*
  • Equipment Design
  • Female
  • Gentamicins / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Renal Dialysis*
  • Sepsis / prevention & control*


  • Anti-Bacterial Agents
  • Gentamicins