Background. Antimicrobial lock solutions may be an effective strategy to prevent catheter-associated infections. However, there remains concern about their efficacy and safety. Methods. To investigate the efficacy of antimicrobial lock therapy to prevent central line-associated bloodstream infections (CLABSIs), we performed a systematic search of PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, from the earliest date up to 31 December 2013. Studies were

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... gible if they were randomized controlled trials comparing antimicrobial lock solutions to heparin and if they provided an appropriate definition of infection. Results. The 23 included studies reported data on 2896 patients, who were predominantly adult patients undergoing hemodialysis (16/23 studies), but also adult and pediatric oncology patients, critically ill neonates, and patients receiving total parenteral nutrition. The use of antimicrobial lock solutions led to a 69% reduction in CLABSI rate (relative risk [RR], 0.31; 95% confidence interval [CI], .24-.40) and a 32% reduction in the rate of exit site infections (RR, 0.68; 95% CI, .49-.95) compared with heparin, without significantly affecting catheter failure due to noninfectious complications (RR, 0.83; 95% CI, .65-1.06). All-cause mortality was not different between the groups (RR, 0.84; 95% CI .64-1.12). Neither the type of antimicrobial solution nor the population studied, affected the relative reduction in CLABSIs, which also remained significant among studies reporting baseline infection rates of <1.15 per 1000 catheter-days, and studies providing data for catheter-related bloodstream infections. Publication and selective reporting bias are a concern in our study and should be acknowledged. Conclusions. Antimicrobial lock solutions are effective in reducing risk of CLABSI, and this effect appears to be additive to traditional prevention measures. Central line-associated bloodstream infections (CLAB-SIs) are the most costly healthcare-associated infections, averaging $45 814 on a per-case basis [1] . A recent analysis found that 65%-70% of CLABSIs could be prevented with the proper institution of catheter care measures [2] . Despite high compliance with such measures, the incidence of CLABSIs is significantly decreased but not completely eliminated across the United States [2, 3]. As such, additional preventive interventions have been investigated. An intervention that is the source of much discussion at the national and international level is the use of antimicrobial lock solutions. Indeed, over the past few years, randomized trials have addressed the issue with promising results [4, 5] . However, concerns regarding